Pair your accounts.

Export articles to Mendeley

Get article recommendations from ACS based on references in your Mendeley library.

Pair your accounts.

Export articles to Mendeley

Get article recommendations from ACS based on references in your Mendeley library.

You’ve supercharged your research process with ACS and Mendeley!

STEP 1:
Click to create an ACS ID

Please note: If you switch to a different device, you may be asked to login again with only your ACS ID.

Please note: If you switch to a different device, you may be asked to login again with only your ACS ID.

Please note: If you switch to a different device, you may be asked to login again with only your ACS ID.

MENDELEY PAIRING EXPIRED
Your Mendeley pairing has expired. Please reconnect
ACS Publications. Most Trusted. Most Cited. Most Read
Effect of the Polarity of Solvents on Periodic Precipitation: Formation of Hierarchical Revert Liesegang Patterns
More

OR SEARCH CITATIONS

My Activity
Publications

Figure 1Loading Img
Download Hi-Res ImageDownload to MS-PowerPointCite This:J. Phys. Chem. B 2022, 126, 41, 8322-8330
  • Open Access
B: Liquids; Chemical and Dynamical Processes in Solution

Effect of the Polarity of Solvents on Periodic Precipitation: Formation of Hierarchical Revert Liesegang Patterns
Click to copy article linkArticle link copied!

Open PDFSupporting Information (1)

The Journal of Physical Chemistry B

Cite this: J. Phys. Chem. B 2022, 126, 41, 8322–8330
Click to copy citationCitation copied!
https://doi.org/10.1021/acs.jpcb.2c05810
Published October 11, 2022

Copyright © 2022 The Authors. Published by American Chemical Society. This publication is licensed under

CC-BY 4.0 .

Abstract

Click to copy section linkSection link copied!
High Resolution Image
Download MS PowerPoint Slide

Liesegang pattern (LP) is one example of self-organized periodic precipitation patterns in nonequilibrium systems. Several studies have demonstrated that the LP morphology can track physicochemical environmental conditions (e.g., temperature); however, the polarity effect has not been explored to date. In this study, a copper chromate system is used to reveal the impact of solvent polarity on the evolving LP structure using water/organic solvent mixtures. In the typical case of using water/dimethyl sulfoxide (DMSO) mixtures, two drastic changes in LP morphology with increasing DMSO contents were found: (i) increasing frequency of the original structure and (ii) formation of a hierarchical pattern with the appearance of another, lower-frequency structure. Furthermore, the simulation model operating with a bimodal size distribution, allowing both homogeneous and heterogeneous precipitations showed good agreement with the experimental results. Therefore, this study demonstrated that LP can be tailored by solvent polarity and can be used for designing hierarchical precipitation patterns in a straightforward manner.

This publication is licensed under

CC-BY 4.0 .
  • cc licence
  • by licence
Copyright © 2022 The Authors. Published by American Chemical Society

Subjects

what are subjects

1. Introduction

Click to copy section linkSection link copied!
Out of equilibrium conditions control various self-assembly and self-organization processes in biological, physical, geochemical, and chemical systems. (1,2) These processes are important in the formation and design of artificial hierarchical structures with high functionality like those found in nature. (3−5) The Liesegang phenomenon (Liesegang pattern (LP) or periodic precipitation) is one of the examples of self-organized chemical patterns with periodic layered structures in nonequilibrium systems. (6−8) This type of pattern formation occurs in a porous medium (typically in hydrogels), in which a homogeneously distributed electrolyte (X–, inner electrolyte) is in contact with another medium containing another electrolyte (M+, outer electrolyte). (9−11) A periodic array of precipitate (MX) forms due to the diffusion of M+ into the gel and a reaction with X– (M+ + X– → MX). The periodicity of the typical LPs shows a general property, namely the distances of bands measured from the gel interface are the members of a geometric progression. This empirical rule is known as the spacing law (12−14)
limn→∞⁡xn+1xn=1+p
(1)
where n is the band number, xn and xn+1, are the distance of the nth and (n + 1)th bands measured from the interface between media containing M+ and X–, and p is the spacing coefficient, which is constant at large values of n. Furthermore, the inter-band spacing (Δxn) deduced by the spacing law is given by
Δxn=xn+1−xn
(2)
Generally, Δxn increases with increasing n, and this type of pattern is called regular LP. (9,14) The regular-type LP generation can be observed in the CuCrO4 system and many other precipitation systems. (9,14−20) However, when Pb2+ is used instead of Cu2+ as an outer electrolyte, exceptional LP can be formed, in which Δxn decreases in contrast to the regular-type pattern, which is the so-called revert (invert) LP. (21−23) This difference was discussed from the perspective of the property of colloidal stability. (24−27) Also, some LPs sometimes showed the formation of hierarchical layered structures with the coexistence of two patterns with different frequencies of periodicity. (21,28,29) Furthermore, recent studies on LPs have focused on investigating, in both simulations and experiments, how the periodicity of LPs is controlled and designed in response to physical and chemical conditions of the environment (such as the temperature, (30) gel concentration, (15) direct and alternating electric field, (31,32) and mechanical deformation of the gel (16)). These factors can affect the precipitation by influencing the diffusion of M+, the chemical reaction between M+ and X–, and the nucleation and aggregation of the precipitate.
It is known that solvent polarity affects the stability of colloidal particles. (33−37) Therefore, the polarity can also modify the routes to precipitation thus affecting the morphology and periodicity of the pattern formed. In this study, we investigate the effect of solvent polarity on the LP structures in the copper chromate precipitation system in an agarose gel. We used a mixture of water and dimethyl sulfoxide (DMSO), a popular aprotic solvent, for the gel preparation, and we changed the volume ratio (φDMSO) to control the polarity of the dispersing media. The relative dielectric constants (εr) of water and DMSO are 78 and 47 at 20 °C, (38) respectively; since lower εr indicates a lower polarity, by increasing φDMSO the polarity in gels is reduced. In our experiments, we found that, by decreasing the polarity of the system, the global structure of the obtained pattern shifted from the regular-type to the revert-type. Furthermore, the regular-type had a fine periodic structure with a length scale (100 μm) smaller than the formed revert pattern itself (∼1 cm). This represents the formation of hierarchical LPs where different periodicities coexist. To extend our concept, we investigated the pattern formation using other common organic solvents (N,N-dimethylformamide (DMF), ethylene glycol (EG), tert-butyl alcohol (TBA), glycerol (GL), and glycerol carbonate (GC)).

2. Experimental Section

Click to copy section linkSection link copied!

2.1. Reagents and Instrument

Agarose powder (Type I) as a reaction medium, copper (II) chloride (CuCl2, 97%) as the outer electrolyte, potassium chromate (K2CrO4, ≥99.0%) as the inner electrolyte, and EG (≥99.5%), GL (≥99.5%), DMF (≥99%), DMSO (≥99.9%), and TBA (≥99.5%) were purchased from Sigma-Aldrich. All reagents were used without further purification. Pattern formation experiments were carried out in glass test tubes with a diameter of 10 mm. The line profile analysis was performed using ImageJ software. The particle size distribution and ζ potential were measured using dynamic light scattering (DLS) measurement with a Malvern Zetasizer NanoZS (Malvern Panalytical) at 25 °C.

2.2. Pattern Formation in Organic Solvents/Water Gels with Different Volume Fractions of Organic Solvents (φOS)

Agarose powder was added to ultrapurified water, and this mixture was continuously stirred using a magnetic stirrer (150 rpm) at 90 °C until complete dissolution of the agarose, making the solution transparent. Subsequently, this solution was cooled at room temperature until the temperature of the solution dropped below 70 °C. This temperature was determined by considering the lowest boiling point of the organic solvents used in this study (TBA, 82 °C). After cooling, the organic solvent was added to this solution with prescribed φOS between water and organic solvents, and a concentrated aqueous solution of K2CrO4 (typically 10–1 M) was also added to this mixture. This agarose sol was added to a glass test tube at a height of 2:3 from the bottom (usually ∼65 mm). The concentration of agarose and K2CrO4 were fixed at 1.0% w/v and 1.0 × 10–2 M. Subsequently, this sample was cooled in a refrigerator at ∼5 °C overnight to complete the gelation process. After gelation, the gel column was allowed to stand for 1 h at room temperature, and then a mixture of water and organic solvents containing CuCl2 (0.5 M, 1.5 mL) was poured on the top of the gel. The same volume ratio of organic solvents/water (φOS) was used in the gel (K2CrO4) and in the outer electrolyte (CuCl2) as well. All experiments on pattern formation were carried out at room temperature, and the time of the pattern formation was 1 week. The periodicity of the patterns was determined using a line profile analysis (Figure S1 in the Supporting information (SI)).

2.3. Measurements of the CuCrO4 Particle Size

First, the water/organic solvent mixture with K2CrO4 was prepared in a quartz cuvette (1 cm × 1 cm). Subsequently, the CuCl2 solution was added to this mixture and mixed by repeated pipetting up and down 10 times. Concentrations of K2CrO4 and CuCl2 were fixed at 1.0 × 10–4 M, only φOS was changed by adjusting the mixing volume ratio between water and organic solvents. Immediately after mixing, this colloid dispersion was measured by DLS at 25 °C to obtain the size distribution and average particle size.

2.4. Measurements of the ζ Potential

The same as in the size measurement, CuCl2 was mixed with K2CrO4 in the water/organic solvent mixture with different φOS. Also, concentrations of CuCl2 and K2CrO4 were the same as in the size measurement. Immediately after mixing, this dispersion was replaced in a folded capillary cell (Malvern DTS1070), then the ζ potential was measured at 25 °C.

3. Results and Discussion

Click to copy section linkSection link copied!
Figure 1a shows the patterns obtained after one week at different φDMSO values. When φDMSO = 0 (the solvent is pure water), a clear periodic precipitation pattern with alternating precipitation and inter-band (no precipitate) regions was formed. Since Δxn increased with the distance measured from the liquid–gel interface, the produced pattern was the regular-type LP. When φDMSO increased from 0 to 0.1, Δxn was found to decrease, thus producing a higher frequency pattern, although the morphology of the regular-type was preserved. In the case of φDMSO = 0.2, a different trend was observed: while maintaining the overall regular morphology, the formation of a clear precipitate in the inter-band regions was observed. The structure of the pattern was further changed when φDMSO was increased up to 0.3. The frequency of the bands increased, and the precipitate formed in the inter-band regions self-organized into a secondary structure having a lower frequency with respect to the primary pattern. Interestingly, in the secondary structure, the distance between the precipitate bands became smaller further away from the liquid–gel interface, generating a revert-type LP. (21−23) However, the primary (higher frequency) structure remained regular and the distance between the bands increased toward the bottom of the test tube (Figure 1b(i)). Therefore, the global periodicity of the pattern switched from regular to the revert-type when φDMSO was changed from 0.2 to 0.3. High and low-frequency patterns coexisted in the system in a way that the low-frequency pattern is the revert one. Although some previous studies have reported two types of coexistence so far, these are classified into the following two types: coexistence of (i) two independent regular-type structures with high and low frequencies (28,29) or (ii) revert-type with low frequency and local structure in-between regular- and equidistant-type with high frequency. (21) Therefore, our pattern structure represents a new class of hierarchical LPs.

Figure 1

Figure 1. (a) Pattern formation of the CuCrO4 system using different volume ratios of DMSO (φDMSO) ranging from φDMSO = 0 (pure water) to φDMSO = 0.5 (water:DMSO = 50%:50%). (b) Enlarged optical photographs of regions (i)–(iii) in (a).

High Resolution Image
Download MS PowerPoint Slide
On increasing φDMSO to 0.5, the original high-frequency primary pattern tended to disappear, and it could be seen only in the regions of the low-frequency pattern (Figure 1b(ii),(iii)). Indeed, this change in the distribution of the primary patterns was also observed using optical microscopy (Figure S2 in the SI). Also, the time course of pattern formation for φDMSO = 0, 0.3, and 0.5 showed that the formation of bands with high-density precipitation and regions with low-density precipitation alternated from top to bottom in both high- and low-frequency patterns (Figures S3–S5 in the SI). Therefore, the phenomena in this system can be explained by a nucleation-particle aggregation-based mechanism (pre-nucleation model) that is frequently employed to understand Liesegang systems. (12,39−41)
To extend the effect of polarity, we also used other organic solvents: DMF (εr = 40) (42) as another aprotic solvent and EG (εr = 38), (43) TBA (εr = 12), (44) GL (εr = 47), and GC (εr = 116) (45−47) as protic solvents (Figures S6–S9 in the SI). In the case of DMF, there was no revert pattern formation, while the frequency of the primary pattern increased as the DMF content increased (Figure S6 in the SI). In contrast, EG and TBA showed a transition similar to the case observed in DMSO (Figures S7 and S8 in the SI). Therefore, the pattern transition from regular to revert-type and formation of the low-frequency pattern structure occurred regardless of the type of solvents (protic or aprotic). Furthermore, it was suggested that periodicity could be controlled by the polarity because the length scale of both structures with lower and higher frequency depending on the type and the volume ratios of the solvents.
To explore the details of the abovementioned transition of the morphology and the periodicity of the obtained patterns, a line profile analysis in Figure 1a was performed (Figure 2a). When φDMSO = 0–0.1, precipitation regions appeared as sharp peaks, and the inverted gray value showed spatial periodicity. Furthermore, the interval between two successive peaks increased with the distance from the gel surface. Therefore, the regular-type periodic precipitation pattern (LP) was formed. The baseline oscillated in space around x = 30–45 mm at φDMSO = 0.2, which indicated the presence of two types of regions having different amounts of precipitate, as seen in Figure 1a. Furthermore, broad peaks (e.g., at x = 18–25 mm) appeared periodically throughout the pattern at φDMSO = 0.3, and a high-frequency pattern was superimposed on the low-frequency pattern (Figure 2a(i)). One low-frequency zone contained ∼10 precipitation bands from the high-frequency pattern. With further increase of φDMSO, the amplitude of the oscillation of the high-frequency pattern decreased (φDMSO = 0.4, Figure 2a(ii)), and the high-frequency pattern disappeared, only the low-frequency revert pattern dominated at φDMSO= 0.5. Also, we analyzed the variation of the width of nth band (wn) in xn for the revert-type bands (low-frequency patterns) obtained at φDMSO = 0.3–0.5 (Figure S10 in the SI). Previous experiments and simulations showed that wn usually increases linearly with increasing xn (wn ∼ xn: so-called width law) for the regular-type LPs, which means that the density of material in each band is constant, and they satisfy the mass conservation. (48,49) In contrast, the obtained revert patterns in this study showed a linear decrease in wn with increasing xn, which indicates that the revert-type LPs should satisfy the inverted form of the classical width law for the regular-type LPs.

Figure 2

Figure 2. (a) Line profile analysis of the LPs starting from the liquid–gel interface (position = 0) to the bottom of test tubes at various DMSO contents. (b) Enlarged views of the regions (i) and (ii) are indicated as dotted line squares in (a). (c) Relationship between the spacing coefficient (p) and φDMSO. The plot was fitted by a power function (f(x) = f(0) + αxβ, where α and β are coefficients). Error bars were obtained from 5 replicates, which were calculated using p-values < 0.05.

High Resolution Image
Download MS PowerPoint Slide
Profiles of the patterns obtained using other solvents also showed a good agreement with the trend obtained in DMSO (Figure S11 in the SI). In particular, EG had a very similar pattern of transition behavior. We can conclude that lowering the polarity of the gel medium leads to a global pattern transition from the regular to the revert one with a hierarchical structure, namely the coexistence of high and low-frequency precipitation regions. Figure 2c shows the relationship between the spacing coefficient (eq 1) and φDMSO, where p is calculated from the primary regular-type at φDMSO = 0–0.1 and the high-frequency pattern above φDMSO = 0.2. The spacing coefficient decreases exponentially with the DMSO content. Furthermore, this change showed a good agreement with a fitting curve based on the power function. Other solvents also showed a similar trend (Figure S12 in the SI), the decreasing polarity reduces the inter-band spacing of regular LPs and facilitates the formation of revert hierarchical precipitation structures.
To obtain more information about the possible mechanism of the pattern transition and the formation of low-frequency bands, we measured the particle size and ζ potential of CuCrO4 particles formed in water/DMSO mixtures with different φDMSO. Figure 3a shows the size distribution measured by dynamic light scattering (DLS). When φDMSO = 0, a rather broad peak centered at 300 nm is obtained, which narrows and decreases until φDMSO = 0.2. At φDMSO = 0.3 and 0.4, a bimodal distribution appeared, the value of the smaller size peak was less than 100 nm, the second one is greater than 200 nm. The size at the 1st peak (corresponding to smaller particles) decreased monotonically with φDMSO and slightly increased at φDMSO = 0.5 (Figure 3b). At the same time, the ζ potential shows a pronounced increase with increasing DMSO content (Figure 3c). Particles had a positive ζ potential (∼10 mV) in water (φDMSO = 0), indicating excess Cu2+ ion adsorption at the surface of the CuCrO4 particles. The measured ζ potential peaked around 40 mV at φDMSO = 0.3, while a further increase of the DMSO content decreases its value. The reason why the ζ potential increased up to φDMSO = 0.3 is that the decreasing dielectric constant of the embedding medium leads to improvement of electric repulsion because εr is in the denominator in the relationship of electrostatic interaction. (50) Furthermore, it has to be noted that the ζ potential increase is accompanied by decreasing DLS size (Figure 3a,b), which indicates a more stable nanoparticle dispersion as a result of increased electric double-layer repulsion. The apparent decrease of the ζ potential above φDMSO = 0.3 can be attributed to the loss of particle stability, also reflected in the appearance of a second peak on the DLS graph. On the other hand, as with decreasing solvent polarity the attractive dispersion interaction increases rapidly, (50) after a given DMSO content, an increase in attraction will dominate, resulting in the partial loss of colloid stability, hence a larger DLS size. Similar measurements were carried out for DMF, EG, and TBA as well (Figure S13 in the SI), leading qualitatively to the same results. It has to be pointed out, that the solvent composition where particle stability is lost, correlates with the dielectric constant of each added solvent; the lower its value, the smaller volume fraction, which is sufficient to induce the formation of a population with a larger size. This bimodal distribution has important implications for the formation of complex patterns in the gels, as in this case, two different precipitation processes can take place with different kinetics. (28,29,51) Also, this bimodal distribution appeared only in the presence of agarose (Figure S14a,b in the SI). Furthermore, the existence of two different precipitation processes was strongly supported by the kinetics of the particle size measurements in the water/DMSO mixture with a low concentration of agarose (Figure S14c in the SI), where the rate of increase in the hydrodynamic size of the peak for bigger particles in the bimodal distribution was greater than that for the peak for smaller particles due to the electrostatic stabilization. Therefore, this distribution was likely to result from a relatively fast precipitation process (heterogeneous precipitation) facilitated by the presence of agarose for unstable particles due to the decrease in polarity and a relatively slow process, in which the remaining electrostatically stabilized particles themselves form precipitates (homogeneous precipitation). Based on this, a possible mechanism to explain why the hierarchical structure was formed with decreasing polarity is proposed as follows. Since a major component of the system at φDMSO = 0 is unstable colloidal particles with low ζ potential, the heterogeneous process dominates the precipitation and the high-frequency pattern formation. However, the proportion of electrostatically stable particles increases with increasing φDMSO, the contribution of the homogeneous process increases, and the system creates bimodal distribution (i.e., the competition between the heterogeneous and homogeneous process), which induces the formation of low-frequency and hierarchical patterns. Furthermore, because the peak with bigger particles finally unified with the peak of smaller particles, and the bimodal distribution disappeared at φDMSO = 0.5, the homogeneous process becomes the dominant process in the pattern formation mechanism instead of the heterogeneous process, which induces localizing and reducing the abundance of high-frequency pattern as shown in Figures 1b, 2a,b, and S2 in the SI.

Figure 3

Figure 3. (a) Size distribution of CuCrO4 colloidal particles in aqueous solution with different φDMSO, measured by dynamic light scattering (DLS). (b) Relationship between the mean particle size at the 1st peak (with a smaller size in bimodal distribution) and φDMSO. (c) Relationship between the ζ potential of CuCrO4 particles and φDMSO. Error bars were obtained from 3 replicates, which were calculated using p-values < 0.05.

High Resolution Image
Download MS PowerPoint Slide
We also performed numerical simulations to verify the validity of the above possible mechanism. As we mentioned above, we considered the homogeneous and heterogeneous precipitation processes, where nucleation and aggregation of a small-size species take place in the solvent phase (homogeneous precipitation), with the eventual deposition of the aggregates on agarose, which itself acts as a source of heterogeneous precipitation as well. The latter allows for the formation of large species directly on the biopolymer matrix. We assumed that a competition of these two processes forms both the high and low-frequency patterns in the system. The following mechanism was used in the simulations:
Homogeneous precipitation process:
A+B→C⁣r1=k1ab
(3)
C+C→2D⁣r2=k2c2,whenc>c*andg>g*,otherwiser2=0
(4)
C+D→2D⁣r3=k3cd
(5)
D+D→2E⁣r4=k4d2
(6)
Heterogeneous precipitation process:
A+B→F⁣r5=k5ab
(7)
F+F→2G⁣r6=k6f2,whenf>f*,otherwiser6=0
(8)
F+G→2G⁣r7=k7fg
(9)
A+B+G→2G⁣r8=k8abg
(10)
The reaction between Cu2+ (A) and CrO42– (B) produces seeds (C) (eq 3), and C turns into bigger nanoparticles (D) by growth and aggregation (eq 4) and autocatalytic aggregation (eq 5), D finally transforms into an immobile precipitate (E) (eq 6). In a competitive process, the seeds attached to the agarose network (F) are formed through heterogeneous nucleation (eq 7), and precipitate (G) is directly formed from F by aggregation and precipitation because the diffusion of particles is limited on the agarose matrix (eq 8). Equations 9 and 10 represent autocatalytic aggregation and precipitation. r1–r8 are the reaction rates for each process, and k1–k8 are the corresponding rate constants. a, b, c, d, e, f, and g are the concentrations of A, B, C, D, E, F, and G, respectively. c*, f*, and g* are the threshold concentrations. These processes can be expressed by the following set of partial differential equations (reaction-diffusion equations)
∂a∂t=DA(φ)∂2a∂x2−k1ab−k5ab−k8abg
(11)
∂b∂t=DB(φ)∂2b∂x2−k1ab−k5ab−k8abg
(12)
∂c∂t=∂∂x(DC(x)∂c∂x)+k1ab−k2c2Θ(c−c*(x))Θ(g−g*)−k3cd
(13)
∂d∂t=DD∂2d∂x2+k2c2Θ(c−c*(x))Θ(g−g*)+k3cd−k4d2
(14)
∂e∂t=k4d2
(15)
∂f∂t=Df(φ)∂2f∂x2+k5ab−k6f2Θ(f−f*)−k7fg
(16)
∂g∂t=k6f2Θ(f−f*)+k7fg+k8abg
(17)
where DA, DB, Dc, DD, and DF are the diffusion coefficients of A, B, C, D, E, F, and G, respectively. In the model, DA, DC, DF, and c* are expressed as functions of the volume fraction (φ) and distance (x) based on the experimental results (for details see the SI) to relate the polarity effect to the reaction-diffusion kinetics in the Liesegang system with CuCrO4 precipitates. Briefly, DA(φ) and DF(φ) were expressed as decreasing functions of φ. In fact, the diffusion rate of Cu2+ was strongly decelerated by increasing φ (Figure S15 in the SI), while the ζ potential increased with φ (Figure 3c), revealing a stronger interaction of the particles with the agarose matrix. On the other hand, the polarity dependence of DF was not applied to DD since D was defined as one of the chemical species for the homogeneous process, and there is no electrostatic interaction between D and agarose. Due to the diffusion of the outer electrolyte (CuCl2) into the gel, the concentration of the Cu2+ ions decreases as we go away from the interface. The lower copper ion concentration decreases the surface charge, which results in less stable particles (c* decreases). Also, some previous studies showed that the particle size increased in the distance measured from the gel–liquid interface in Liesegang systems, (52) we expected that a decrease in c* also led to increasing the particle size. In summary, this effect might have two consequences for the CuCrO4 particles without binding to the agarose: (i) the diffusion coefficient of C decreases due to the increase in particle size, and (ii) the aggregation threshold decreases in x. Therefore, we expressed both DC and c* as decreasing functions of x as discussed in some previous studies. (21−23,25,26) Furthermore, these studies showed that the decreasing function of threshold was mainly contributed by revert LP. Therefore, we predicted that the low-frequency revert LP emerged when the homogeneous process is pronounced by the stabilization of particles due to the increase in φ. In contrast to the expression of DC, we applied that DD was independent of the position (x). According to the previous study which investigated the diffusivity of nanoparticles in a gel medium, the diffusion coefficient of particles decreased inversely with the hydrodynamic radius. (53) This result indicates that differences in diffusion coefficients due to size differences between relatively large particles are not significant. Since D corresponds to bigger particles than C, the size effect on the diffusivity of D should be less than C. Therefore, we used the expression without the dependency of position for DD. The details of the numerical model and the simulations (including information for all parameters) can be found in the SI.
The simulation results provided a qualitative agreement with the results of global transition and formation of high and low-frequency patterns observed in the experiments (Figures 4 and S16 in the SI). When φ = 0, the regular LP was formed (Figure 4a left panel), the same as in the experiment at φDMSO = 0. As φ was increased, the frequency of the primary patterns increased and the low-frequency pattern appeared generating a superimposed high-frequency pattern on the low-frequency one (Figure 4a middle panel). In the case of φ = 0.5, the high-frequency pattern disappeared completely in the system leaving only low-frequency revert patterns (Figure 4a right panel). These trends become more vivid by obtaining concentration profiles of E and G (Figure 4b). This result shows a good agreement with the experimental results (Figures 2b and S2 in the SI). Also, the contribution of each process is shown in Figure S17 in the SI, where the homogeneous process formed low-frequency revert LPs with increasing φ, while the heterogeneous process promoted high-frequency regular LP formation. Therefore, based on the simulation results, we can propose that the pattern transitions and the formation of the superimposed high and low-frequency patterns are driven by the polarity of the solvent and governed by two precipitation pathways with different reaction rates.

Figure 4

Figure 4. (a) Effect of φ on the pattern structure in simulations (φDMSO in experiments), where φ = 0 and 0.5 correspond to conditions of pure water and water/DMSO mixture of 1:1. Color changes from green to yellow show the sum of concentrations (e + g) of species E and G. (b) Concentration profiles of E + G in simulations at various φ. Regions surrounded by the dotted line square at φ = 0.3–0.5 are inserted into the right panel of each condition as enlarged graphs. Gray regions in enlarged graphs correspond to the formation of the low-frequency revert patterns.

High Resolution Image
Download MS PowerPoint Slide

4. Conclusions

Click to copy section linkSection link copied!
In summary, in experiments on the precipitation of CuCrO4 in different mixtures of water and various organic solvents (DMSO, DMF, EG, TBA, and GC), we have demonstrated that the polarity of the medium in a hydrogel matrix affects the morphology of LP. We interpreted the observed results with the support of numerical simulation based on the homogeneous and heterogeneous precipitation processes. Typically, depending on the DMSO content (i.e., overall polarity of the solvent mixture), (i) we could control the frequency of regular LPs (Figure 2c), and (ii) the global periodicity transited from regular to revert patterns, we finally obtained the hierarchical pattern coexisting with the revert low-frequency pattern with superimposed high-frequency regular pattern (Figures 1b and 2b). Similar trends were also observed in some other organic solvents as well. The results of size and ζ potential measurements showed the possibility that the competition of two different precipitation processes was induced depending on the polarity of the medium. Based on this result, we constructed one possible model, and simulation using this model showed good qualitative agreement with experimental observations. According to this behavior, LP could be employed for practical purposes to track the polarity changes in unknown solvents, similar to the use of LPs for tracking environmental changes. (15,16,30) Moreover, tuning the solvent polarity can be a promising strategy to control, tailor, and design both regular LPs and new hierarchical structures. In addition, hierarchical layered structures are of great importance for the design of self-organized functional materials from nano- to macroscale. (3−5) Some recent studies showed that LPs can be formed using some functional materials (e.g., metal nanoparticles and metal–organic frameworks), and another study indicated how to form microscale periodicity. (17,20,54,55) By combining this knowledge with our strategy of polarity-based LP control, LP could be a potential candidate for the generation of self-organized hierarchical layered structures with various functions and structures.

Supporting Information

Click to copy section linkSection link copied!

The Supporting Information is available free of charge at https://pubs.acs.org/doi/10.1021/acs.jpcb.2c05810.

  • Procedures for the synthesis of GC, solubility product (Ksp) measurements, and line profile analysis, detail of numerical simulation and model; results of optical microscopy observations, time-course, pattern formation with organic solvents (DMF, EG, TBA, GL, and GC), line profile, spacing coefficient, DLS, and ζ potential measurements, Ksp measurements, diffusion of Cu2+, and simulations (PDF)

Terms & Conditions

Most electronic Supporting Information files are available without a subscription to ACS Web Editions. Such files may be downloaded by article for research use (if there is a public use license linked to the relevant article, that license may permit other uses). Permission may be obtained from ACS for other uses through requests via the RightsLink permission system: http://pubs.acs.org/page/copyright/permissions.html.

Author Information

Click to copy section linkSection link copied!
  • Corresponding Authors
    • István Lagzi - ELKH-BME Condensed Matter Research Group, Budapest University of Technology and Economics, Műegyetem rakpart 3, Budapest1111, Hungary;  Department of Physics, Institute of Physics, Budapest University of Technology and Economics, Budafoki út 8, Budapest1111, Hungary;  Orcidhttps://orcid.org/0000-0002-2303-5965;  Email: [email protected]
    • Masaki Itatani - Department of Physics, Institute of Physics, Budapest University of Technology and Economics, Budafoki út 8, Budapest1111, Hungary;  Orcidhttps://orcid.org/0000-0003-1025-0452;  Email: [email protected]
  • Authors
    • Gábor Holló - ELKH-BME Condensed Matter Research Group, Budapest University of Technology and Economics, Műegyetem rakpart 3, Budapest1111, Hungary
    • Dániel Zámbó - Institute of Technical Physics and Materials Science, Centre for Energy Research, Konkoly-Thege Miklós út 29-33, H-1121Budapest, Hungary;  Orcidhttps://orcid.org/0000-0001-7671-039X
    • András Deák - Institute of Technical Physics and Materials Science, Centre for Energy Research, Konkoly-Thege Miklós út 29-33, H-1121Budapest, Hungary
    • Federico Rossi - Department of Earth, Environmental and Physical Sciences─DEEP Sciences, University of Siena, Pian dei Mantellini 44, 53100Siena, Italy;  Orcidhttps://orcid.org/0000-0002-1854-532X
    • Raffaele Cucciniello - Department of Chemistry and Biology “Adolfo Zambelli”, University of Salerno, Viale Via Giovanni Paolo II 132, 84084Fisciano, Salerno, Italy;  Orcidhttps://orcid.org/0000-0002-3291-7273
    • Pierandrea Lo Nostro - Department of Chemistry ‘Ugo Schiff”, University of Florence, Via della Lastruccia 3, 50019Sesto Fiorentino, Florence, Italy
    • Hideki Nabika - Faculty of Science, Yamagata University, 1-4-12, Kojirakawa, Yamagata990-8560, Japan;  Orcidhttps://orcid.org/0000-0002-7780-8433
    • Bilge Baytekin - Department of Chemistry and UNAM, Bilkent University, 06800Ankara, Turkey;  Orcidhttps://orcid.org/0000-0002-3867-3863
  • Author Contributions

    F.R., B.B., and I.L. conceived the study. M.I. carried out the experiments, data analysis, and prepared the draft. G.H. constructed the numerical model and performed the simulations based on the discussion with M.I. and I.L. D.Z. and A.D. supported experiments and discussion regarding the measurements of particle size and ζ potential. GC was synthesized by F.R., R.C., and P.L.N. All authors interpreted the data. The manuscript was written through contributions of all authors.

  • Notes
    The authors declare no competing financial interest.

Acknowledgments

Click to copy section linkSection link copied!

This work was supported by JSPS Overseas Challenge Program for Young Researchers (Identification Number 202180075), JSPS Postdoctoral Fellowship Program for Overseas Researchers (Identification Number 202260298), the National Research, Development, and Innovation Office of Hungary (K131425, FK128327, and FK142148), and the National Research, Development, and Innovation Fund of Hungary under Grant TKP2021-EGA-02 and TKP2021-NKTA-05.

Abbreviations

Click to copy section linkSection link copied!
LP

Liesegang pattern

EG

ethylene glycol

GL

glycerol

DMF

N,N-dimethylformamide

DMSO

dimethyl sulfoxide

TBA

tert-butyl alcohol

DLS

dynamic light scattering

εr

relative dielectric constants

References

Click to copy section linkSection link copied!

This article references 55 other publications.

  1. 1
    Grzybowski, B. A.; Bishop, K. J. M.; Campbell, C. J.; Fialkowski, M.; Smoukov, S. K. Micro- and Nanotechnology via Reaction–diffusion. Soft Matter 2005, 1, 114– 128,  DOI: 10.1039/b501769f
    Google Scholar
    1
    Micro- and nanotechnology via reaction-diffusion
    Grzybowski, Bartosz A.; Bishop, Kyle J. M.; Campbell, Christopher J.; Fialkowski, Marcin; Smoukov, Stoyan K.
    Soft Matter (2005), 1 (2), 114-128CODEN: SMOABF; ISSN:1744-683X. (Royal Society of Chemistry)
    A review. Reaction-diffusion (RD) processes are common throughout nature, which uses them routinely to build and control structures on length scales from mol. to macroscopic. At the same time, despite a long history of scientific research and a significant level of understanding of the basic aspects of RD, reaction-diffusion has remained an unrealized technol. opportunity. This review suggests that RD systems can provide a versatile basis for applications in micro- and nanotechnol. Straightforward exptl. methods are described that allow precise control of RD processes in complex microgeometries and enable fabrication of small-scale structures, devices, and functional systems. Uses of RD in sensory applications are also discussed.
    >> More from SciFinder ®
    https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD2MXmvFCmtLo%253D&md5=ec155fb4ff1f77feaa1f43e4e47ce656
  2. 2
    Epstein, I. R.; Xu, B. Reaction–diffusion Processes at the Nano- and Microscales. Nat. Nanotechnol. 2016, 11, 312– 319,  DOI: 10.1038/nnano.2016.41
    Google Scholar
    2
    Reaction-diffusion processes at the nano- and microscales
    Epstein, Irving R.; Xu, Bing
    Nature Nanotechnology (2016), 11 (4), 312-319CODEN: NNAABX; ISSN:1748-3387. (Nature Publishing Group)
    The bottom-up fabrication of nano- and microscale structures from primary building blocks (mols., colloidal particles) has made remarkable progress over the past two decades, but most research has focused on structural aspects, leaving our understanding of the dynamic and spatiotemporal aspects at a relatively primitive stage. In this Review, we draw inspiration from living cells to argue that it is now time to move beyond the generation of structures and explore dynamic processes at the nanoscale. We first introduce nanoscale self-assembly, self-organization and reaction-diffusion processes as essential features of cells. Then, we highlight recent progress towards designing and controlling these fundamental features of life in abiol. systems. Specifically, we discuss examples of reaction-diffusion processes that lead to such outcomes as self-assembly, self-organization, unique nanostructures, chem. waves and dynamic order to illustrate their ubiquity within a unifying context of dynamic oscillations and energy dissipation. Finally, we suggest future directions for research on reaction-diffusion processes at the nano- and microscales that we find hold particular promise for a new understanding of science at the nanoscale and the development of new kinds of nanotechnologies for chem. transport, chem. communication and integration with living systems.
    >> More from SciFinder ®
    https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC28Xltlyitbc%253D&md5=7afec526a3ff15b2b3959add1326da4b
  3. 3
    Roth, W. J.; Gil, B.; Makowski, W.; Marszalek, B.; Eliášová, P. Layer Like Porous Materials with Hierarchical Structure. Chem. Soc. Rev. 2016, 45, 3400– 3438,  DOI: 10.1039/C5CS00508F
    Google Scholar
    3
    Layer like porous materials with hierarchical structure
    Roth, Wieslaw J.; Gil, Barbara; Makowski, Waclaw; Marszalek, Bartosz; Eliasova, Pavla
    Chemical Society Reviews (2016), 45 (12), 3400-3438CODEN: CSRVBR; ISSN:0306-0012. (Royal Society of Chemistry)
    Many chem. compns. produce layered solids consisting of extended sheets with thickness not greater than a few nanometers. The layers are weakly bonded together in a crystal and can be modified into various nanoarchitectures including porous hierarchical structures. Several classes of 2-dimensional (2D) materials have been extensively studied and developed because of their potential usefulness as catalysts and sorbents. They are discussed in this review with focus on clays, layered transition metal oxides, silicates, layered double hydroxides, metal(IV) phosphates and phosphonates, esp. zirconium, and zeolites. Pillaring and delamination are the primary methods for structural modification and pore tailoring. The reported approaches are described and compared for the different classes of materials. The methods of characterization include identification by X-ray diffraction and microscopy, pore size anal. and activity assessment by IR spectroscopy and catalytic testing. The discovery of layered zeolites was a fundamental breakthrough that created unprecedented opportunities because of (i) inherent strong acid sites that make them very active catalytically, (ii) porosity through the layers and (iii) bridging of 2D and 3D structures. Approx. 16 different types of layered zeolite structures and modifications have been identified as distinct forms. It is also expected that many among the over 200 recognized zeolite frameworks can produce layered precursors. Addnl. advances enabled by 2D zeolites include synthesis of layered materials by design, hierarchical structures obtained by direct synthesis and top-down prepn. of layered materials from 3D frameworks.
    >> More from SciFinder ®
    https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2MXhs12ksLrN&md5=304044f5744f0a311d4fab337f0a3033
  4. 4
    Shehzad, K.; Xu, Y.; Gao, C.; Duan, X. Three-dimensional Macro-structures of Two-dimensional Nanomaterials. Chem. Soc. Rev. 2016, 45, 5541– 5588,  DOI: 10.1039/C6CS00218H
    Google Scholar
    4
    Three-dimensional macro-structures of two-dimensional nanomaterials
    Shehzad, Khurram; Xu, Yang; Gao, Chao; Duan, Xiangfeng
    Chemical Society Reviews (2016), 45 (20), 5541-5588CODEN: CSRVBR; ISSN:0306-0012. (Royal Society of Chemistry)
    If two-dimensional (2D) nanomaterials are ever to be utilized as components of practical, macroscopic devices on a large scale, there is a complementary need to controllably assemble these 2D building blocks into more sophisticated and hierarchical three-dimensional (3D) architectures. Such a capability is key to design and build complex, functional devices with tailored properties. This review provides a comprehensive overview of the various exptl. strategies currently used to fabricate the 3D macro-structures of 2D nanomaterials. Addnl., various approaches for the decoration of the 3D macro-structures with org. mols., polymers, and inorg. materials are reviewed. Finally, we discuss the applications of 3D macro-structures, esp. in the areas of energy, environment, sensing, and electronics, and describe the existing challenges and the outlook for this fast emerging field.
    >> More from SciFinder ®
    https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC28Xht1ers7jN&md5=7bb7599d233149bc1f2ed7e8d28bc662
  5. 5
    Yang, X.-Y.; Chen, L.-H.; Li, Y.; Rooke, J. C.; Sanchez, C.; Su, B.-L. Hierarchically Porous Materials: Synthesis Strategies and Structure Design. Chem. Soc. Rev. 2017, 46, 481– 558,  DOI: 10.1039/C6CS00829A
    Google Scholar
    5
    Hierarchically porous materials: synthesis strategies and structure design
    Yang, Xiao-Yu; Chen, Li-Hua; Li, Yu; Rooke, Joanna Claire; Sanchez, Clement; Su, Bao-Lian
    Chemical Society Reviews (2017), 46 (2), 481-558CODEN: CSRVBR; ISSN:0306-0012. (Royal Society of Chemistry)
    Owing to their immense potential in energy conversion and storage, catalysis, photocatalysis, adsorption, sepn. and life science applications, significant interest has been devoted to the design and synthesis of hierarchically porous materials. The hierarchy of materials on porosity, structural, morphol., and component levels is key for high performance in all kinds of applications. Synthesis and applications of hierarchically structured porous materials have become a rapidly evolving field of current interest. A large series of synthesis methods have been developed. This review addresses recent advances made in studies of this topic. After identifying the advantages and problems of natural hierarchically porous materials, synthetic hierarchically porous materials are presented. The synthesis strategies used to prep. hierarchically porous materials are first introduced and the features of synthesis and the resulting structures are presented using a series of examples. These involve templating methods (surfactant templating, nanocasting, macroporous polymer templating, colloidal crystal templating and bioinspired process, i.e. biotemplating), conventional techniques (supercrit. fluids, emulsion, freeze-drying, breath figures, selective leaching, phase sepn., zeolitization process, and replication) and basic methods (sol-gel controlling and post-treatment), as well as self-formation phenomenon of porous hierarchy. A series of detailed examples are given to show methods for the synthesis of hierarchically porous structures with various chem. compns. (dual porosities: micro-micropores, micro-mesopores, micro-macropores, meso-mesopores, meso-macropores, multiple porosities: micro-meso-macropores and meso-meso-macropores). We hope that this review will be helpful for those entering the field and also for those in the field who want quick access to helpful ref. information about the synthesis of new hierarchically porous materials and methods to control their structure and morphol.
    >> More from SciFinder ®
    https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC28XhvFOitrfM&md5=d496ddd01cb671880e1b4912f2036bf4
  6. 6
    Liesegang, R. E. Ueber einige Eigenschaften von Gallerten. Naturwiss. Wochenschr. 1896, 11, 353– 362
    Google Scholar
    There is no corresponding record for this reference.
  7. 7
    Nabika, H.; Itatani, M.; Lagzi, I. Pattern Formation in Precipitation Reactions: The Liesegang Phenomenon. Langmuir 2020, 36, 481– 497,  DOI: 10.1021/acs.langmuir.9b03018
    Google Scholar
    7
    Pattern Formation in Precipitation Reactions: The Liesegang Phenomenon
    Nabika, Hideki; Itatani, Masaki; Lagzi, Istvan
    Langmuir (2020), 36 (2), 481-497CODEN: LANGD5; ISSN:0743-7463. (American Chemical Society)
    A review. Pattern formation is a frequent phenomenon in physics, chem., biol. and material science. Bottom-up pattern formation occurs usually in the interaction of the transport phenomena of chem. species with their chem. reaction. The oldest pattern formation is the Liesegang phenomenon (or periodic pptn.), which was discovered and described by Raphael Edward Liesegang in 1896, who was a German chemist and photographer, and he was born 150 years ago. The purpose of this review is to provide a comprehensive overview of this type of pattern formation. Liesegang banding occurs due to the coupling of the diffusion process of the reagents to their chem. reactions in solid hydrogels. We will discuss several phenomena obsd. and discovered in the past century including reverse patterns, pptn. patterns with dissoln. (due to complex formation), helicoidal patterns, and pptn. waves. Addnl., we will review all existing models of the Liesegang phenomenon including pre- and post-nucleation scenarios. Finally, we will highlight several applications of periodic pptn.
    >> More from SciFinder ®
    https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC1MXit1CrsrrN&md5=28efdfec8ee95573c635fcde08b0c8b4
  8. 8
    Nakouzi, E.; Steinbock, O. Self-organization in Precipitation Reactions Far from the Equilibrium. Sci. Adv. 2016, 2, e1601144  DOI: 10.1126/sciadv.1601144
    Google Scholar
    8
    Self-organization in precipitation reactions far from the equilibrium
    Nakouzi, Elias; Steinbock, Oliver
    Science Advances (2016), 2 (8), e1601144/1-e1601144/13CODEN: SACDAF; ISSN:2375-2548. (American Association for the Advancement of Science)
    Far from the thermodn. equil., many pptn. reactions create complex product structures with fascinating features caused by their unusual origins. Unlike the dissipative patterns in other self-organizing reactions, these features can be permanent, suggesting potential applications in materials science and engineering. We review four distinct classes of pptn. reactions, describe similarities and differences, and discuss related challenges for theor. studies. These classes are hollow micro- and macrotubes in chem. gardens, polycryst. silica carbonate aggregates (biomorphs), Liesegang bands, and propagating pptn.-dissoln. fronts. In many cases, these systems show intricate structural hierarchies that span from the nanometer scale into the macroscopic world. We summarize recent exptl. progress that often involves growth under tightly regulated conditions by means of wet stamping, holog. heating, and controlled elec., magnetic, or pH perturbations. In this research field, progress requires mechanistic insights that cannot be derived from expts. alone. We discuss how mesoscopic aspects of the product structures can be modeled by reaction-transport equations and suggest important targets for future studies that should also include materials features at the nanoscale.
    >> More from SciFinder ®
    https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC1cXkslKqt7w%253D&md5=fca00dd5dd11e40c756bdb23f727b1b4
  9. 9
    Lagzi, I. Controlling and Engineering Precipitation Patterns. Langmuir 2012, 28, 3350– 3354,  DOI: 10.1021/la2049025
    Google Scholar
    9
    Controlling and Engineering Precipitation Patterns
    Lagzi, Istvan
    Langmuir (2012), 28 (7), 3350-3354CODEN: LANGD5; ISSN:0743-7463. (American Chemical Society)
    Controlling and engineering chem. structures are the most important scientific challenges in material science. Pptn. patterns from ions or nanoparticles are promising candidates for designing bulk structure for catalysis, energy prodn., storage, and electronics. There are only a few procedures and techniques to control pptn. (Liesegang) patterns in gel media (e.g., using an elec. field, varying the initial concn. of the electrolytes). However, those methods provide just a limited degree of freedom. Here, the authors provide a robust and transparent way to control and engineer Liesegang patterns by varying gel concn. and inducing impurity by addn. of gelatin to agarose gel. Using this exptl. method, different pptn. structures can be obtained with different width and spatial distribution of the formed bands. A new variant of a sol-coagulation model was developed to describe and understand the effect of the gel concn. and impurities on Liesegang pattern formation.
    >> More from SciFinder ®
    https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC38XhsVWjurc%253D&md5=1d4fcca37f4d5f4c3d2b3042f39356ec
  10. 10
    Smoukov, S. K.; Bitner, A.; Campbell, C. J.; Kandere-Grzybowska, K.; Grzybowski, B. A. Nano- and Microscopic Surface Wrinkles of Linearly Increasing Heights Prepared by Periodic Precipitation. J. Am. Chem. Soc. 2005, 127, 17803– 17807,  DOI: 10.1021/ja054882j
    Google Scholar
    10
    Nano- and Microscopic Surface Wrinkles of Linearly Increasing Heights Prepared by Periodic Precipitation
    Smoukov, Stoyan K.; Bitner, Agnieszka; Campbell, Christopher J.; Kandere-Grzybowska, Kristiana; Grzybowski, Bartosz A.
    Journal of the American Chemical Society (2005), 127 (50), 17803-17807CODEN: JACSAT; ISSN:0002-7863. (American Chemical Society)
    Arrays of surface wrinkles of linearly increasing heights (from tens of nanometers to tens of micrometers) were prepd. via a spontaneous reaction-diffusion process based on periodic pptn. The slopes, dimensions, and positions of the pptn. bands could be controlled precisely by adjusting the concns. of the participating chems. as well as the material properties of patterned substrates. Addnl. control of periodic pptn. by localized UV irradn. allowed for the prepn. of discontinuous and curvilinear structures. The nonbinary 3-dimensional surface topogs. were replicated into poly(dimethylsiloxane), and the applications of replicas in microfluidics, microsepns., and cell biol. were suggested.
    >> More from SciFinder ®
    https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD2MXht1CkurzK&md5=a6816a6e8b0bb1789d8cd49f3edd9788
  11. 11
    Badr, L.; Sultan, R. Ring Morphology and pH Effects in 2D and 1D Co(OH)2 Liesegang Systems. J. Phys. Chem. A 2009, 113, 6581– 6586,  DOI: 10.1021/jp8094984
    Google Scholar
    11
    Ring Morphology and pH Effects in 2D and 1D Co(OH)2 Liesegang Systems
    Badr, Layla; Sultan, Rabih
    Journal of Physical Chemistry A (2009), 113 (24), 6581-6586CODEN: JPCAFH; ISSN:1089-5639. (American Chemical Society)
    The authors study the factors that affect the morphol. of Co(OH)2 Liesegang rings, in a way to obtain concentric rings with large spacing, upon an appropriate variation in the exptl. conditions. Such well-resolved patterns are obtained under optimum conditions: decrease in the concn. of the outer electrolyte, increase in the concn. of both the inner electrolyte and the gelatin in the hosting gel medium, and increase in the strength of a const. radial elec. field applied across the pattern domain. The effect of pH on the bands in a 1-dimensional Co(OH)2 Liesegang pattern is also studied. The initial pH of the diffusing soln. plays a central role in altering the band morphol., because the outer electrolyte (NH4OH) is a base, strongly affected by the H+ equil. The no. of bands decreases and the interband spacing increases with decreasing pH of the NH4OH soln. The pattern morphol. in that case is controlled by the NH4Cl/NH4OH ratio.
    >> More from SciFinder ®
    https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD1MXmtF2ks7g%253D&md5=af71ce06cf80b8f1c88666754ef91cbb
  12. 12
    Antal, T.; Droz, M.; Magnin, J.; Rácz, Z.; Zrinyi, M. Derivation of the Matalon-Packter Law for Liesegang patterns. Chem. Phys. 1998, 109, 9479– 9486,  DOI: 10.1063/1.477609
    Google Scholar
    12
    Derivation of the Matalon-Packter law for Liesegang patterns
    Antal, T.; Droz, M.; Magnin, J.; Racz, Z.; Zrinyi, M.
    Journal of Chemical Physics (1998), 109 (21), 9479-9486CODEN: JCPSA6; ISSN:0021-9606. (American Institute of Physics)
    Theor. models of the Liesegang phenomena are studied and simple expressions for the spacing coeffs. characterizing the patterns are derived. The emphasis is on displaying the explicit dependences on the concns. of the inner and the outer electrolytes. Competing theories (ion-product supersatn., nucleation and droplet growth, induced sol-coagulation) are treated with the aim of finding the distinguishing features of the theories. The predictions are compared with expts. and the results suggest that the induced sol-coagulation theory is the best candidate for describing the exptl. observations embodied in the Matalon-Packter law.
    >> More from SciFinder ®
    https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaK1cXntlWgtLk%253D&md5=4ab5e2e2e30b94687d783fc024227bdc
  13. 13
    Thomas, S.; Molnár, F.; Rácz, Z.; Lagzi, I. Matalon–Packter Law for Stretched Helicoids Formed in Precipitation Processes. Chem. Phys. Lett. 2013, 577, 38– 41,  DOI: 10.1016/j.cplett.2013.05.031
    Google Scholar
    13
    Matalon-Packter law for stretched helicoids formed in precipitation processes
    Thomas, Shibi; Molnar, Ferenc; Racz, Zoltan; Lagzi, Istvan
    Chemical Physics Letters (2013), 577 (), 38-41CODEN: CHPLBC; ISSN:0009-2614. (Elsevier B.V.)
    Helicoid-like pptn. structures emerging in the wake of reaction-diffusion fronts are studied exptl. as well as theor. We find that the helicoids are stretched, their local pitch behind the advancing front increases exponentially. We compare this result to the exponential increase of the band spacing in Liesegang phenomena. The spacing coeff. (p) characterizing the exponential increase satisfies the same Matalon-Packter law in both cases, i.e. p ∼ 1/a0 where a0 is the initial concn. of the outer electrolyte in the exptl. setup. Our expts. also reveal that, at the microstructure level, the helicoids are assembled from building blocks of micron-size achiral spherulites.
    >> More from SciFinder ®
    https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3sXptFWgtr0%253D&md5=c724a4cf987d5aa8530a22aead923f66
  14. 14
    Itatani, M.; Fang, Q.; Nabika, H. Modification of the Matalon–Packter Law for Self-Organized Periodic Precipitation Patterns by Incorporating Time-Dependent Diffusion Flux. J. Phys. Chem. B 2021, 125, 6921– 6929,  DOI: 10.1021/acs.jpcb.1c02175
    Google Scholar
    14
    Modification of the Matalon-Packter Law for Self-Organized Periodic Precipitation Patterns by Incorporating Time-Dependent Diffusion Flux
    Itatani, Masaki; Fang, Qing; Nabika, Hideki
    Journal of Physical Chemistry B (2021), 125 (25), 6921-6929CODEN: JPCBFK; ISSN:1520-5207. (American Chemical Society)
    Spontaneous pattern formation is common in both inanimate and living systems. Although the Liesegang pattern (LP) is a well-studied chem. model for pptn. patterns, various recent LP systems based on artificial control could not be easily evaluated using classical tools. The Matalon-Packter (MP) law describes the effect of the initial electrolyte concn., which governs the diffusion flux (Fdiff), on the spatial distribution of LP. Note that the classical MP law only considers Fdiff through the initial concn. of electrolytes, even though it should also depend on the vol. of the reservoir used for the outer electrolyte because of the temporal change in the concn. therein due to diffusion. However, there has been no report on the relationship between the MP law, the reservoir vol., and Fdiff. Here, we exptl. demonstrated and evaluated the effect of the reservoir vol. on LP periodicity according to the classical MP law. Numerical simulations revealed that the reservoir vol. affects the temporal modulation of Fdiff. By expressing the MP law as a function of estd. Fdiff after a certain period of time, we provide a uniform description of the changes in periodicity for both small and large reservoir vols. Such modification should make the MP law a more robust tool for studying LP systems.
    >> More from SciFinder ®
    https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BB3MXhtlWltbjE&md5=57c596530b2cf6b8da8dd55a396bad99
  15. 15
    Itatani, M.; Fang, Q.; Unoura, K.; Nabika, H. Programmable Design of Self-Organized Patterns through a Precipitation Reaction. J. Phys. Chem. B 2020, 124, 8402– 8409,  DOI: 10.1021/acs.jpcb.0c05603
    Google Scholar
    15
    Programmable Design of Self-Organized Patterns through a Precipitation Reaction
    Itatani, Masaki; Fang, Qing; Unoura, Kei; Nabika, Hideki
    Journal of Physical Chemistry B (2020), 124 (38), 8402-8409CODEN: JPCBFK; ISSN:1520-5207. (American Chemical Society)
    Nature uses self-organized spatiotemporal patterns to construct systems with robustness and flexibility. Furthermore, understanding the principles underlying self-organization in nature enables programmable design of artificial patterns driven by chem. energy. The related mechanisms are however not clearly understood because most of these patterns are formed in reaction-diffusion (RD) systems consisting of intricate interaction between diffusion and reaction. Therefore, comprehensive understanding of the pattern formation may provide crit. knowledge for developing novel strategies in both natural science and chem. engineering. Liesegang patterns (LPs) are one of the typical programmable patterns. This study demonstrates that appropriate tuning of gel concn. distribution is a key programming factor for controlling LP periodicities. The gel distribution was realized in bi- or multilayered gels constructed by stacking agarose gels of different concns. Thus, exceptional LP periodicities were achieved locally in bilayered gels. Furthermore, RD simulations revealed that the nucleation process modulated by the gel distribution dets. the LP periodicity in bilayered gels. Finally, based on this concept, desired LP periodicities were successfully realized by programming gel distributions in multilayered gels. Thus, deep insights into the fundamental role of nucleation in designing LPs can lead to the practical applications of LPs and the understanding of self-organization in nature.
    >> More from SciFinder ®
    https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BB3cXitFCls7rN&md5=fd932f5bd48607e6f6517a4482619524
  16. 16
    Morsali, M.; Khan, M. T. A.; Ashirov, R.; Hollo, G.; Baytekin, H. T.; Lagzi, I.; Baytekin, B. Mechanical Control of Periodic Precipitation in Stretchable Gels to Retrieve Information on Elastic Deformation and for the Complex Patterning of Matter. Adv. Mater. 2020, 32, 1905779  DOI: 10.1002/adma.201905779
    Google Scholar
    16
    Mechanical Control of Periodic Precipitation in Stretchable Gels to Retrieve Information on Elastic Deformation and for the Complex Patterning of Matter
    Morsali, Mohammad; Khan, Muhammad Turab Ali; Ashirov, Rahym; Hollo, Gabor; Baytekin, H. Tarik; Lagzi, Istvan; Baytekin, Bilge
    Advanced Materials (Weinheim, Germany) (2020), 32 (10), 1905779CODEN: ADVMEW; ISSN:0935-9648. (Wiley-VCH Verlag GmbH & Co. KGaA)
    Material design using nonequil. systems provides straightforward access to complexity levels that are possible through dynamic processes. Pattern formation through nonequil. processes and reaction-diffusion can be used to achieve this goal. Liesegang patterns (LPs) are a kind of periodic pptn. patterns formed through reaction-diffusion. So far, it has been shown that the periodic band structure of LPs and the geometry of the pattern can be controlled by exptl. conditions and external fields (e.g., elec. or magnetic). However, there are no examples of these systems being used to retrieve information about the changes in the environment as they form, and there are no studies making use of these patterns for complex material prepn. This work shows the formation of LPs by a diffusion-pptn. reaction in a stretchable hydrogel and the control of the obtained patterns by the unprecedented and uncommon method of mech. input. Addnl., how to use this protocol and how deviations from "LP behavior" of the patterns can be used to "write and store" information about the time, duration, extent, and direction of gel deformation are presented. Finally, an example of using complex patterning to deposit polypyrrole by using pptn. patterns is shown as a template.
    >> More from SciFinder ®
    https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BB3cXjt1Omug%253D%253D&md5=e4376d316c43544cd7f735efe3445c80
  17. 17
    Zakhia Douaihy, R.; Al-Ghoul, M.; Hmadeh, M. Liesegang Banding for Controlled Size and Growth of Zeolitic-Imidazolate Frameworks. Small 2019, 15, 1901605  DOI: 10.1002/smll.201901605
    Google Scholar
    There is no corresponding record for this reference.
  18. 18
    Sultan, R.; Halabieh, R. Effect of an Electric Field on Propagating Co(OH)2 Liesegang Patterns. Chem. Phys. Lett. 2000, 332, 331– 338,  DOI: 10.1016/S0009-2614(00)01200-8
    Google Scholar
    18
    Effect of an electric field on propagating Co(OH)2 Liesegang patterns
    Sultan, R.; Halabieh, R.
    Chemical Physics Letters (2000), 332 (3,4), 331-338CODEN: CHPLBC; ISSN:0009-2614. (Elsevier Science B.V.)
    The effect of an applied DC elec. field on the propagation of a Co(OH)2 Liesegang pattern from Co2+ and NH4OH is investigated. The field free pattern is known to propagate down the tube due to band dissoln. at the top and band formation at the bottom. At a fixed concn. of Co2+ (0.134 M), the front propagation is accelerated by the field which is applied in the direction of wave propagation. The pattern propagates faster under a higher voltage. The dependence of wave velocity on field strength is non-linear. When the concn. of Co2+ is varied at const. voltage (6.00 V), two opposite trends are obtained. Below a characteristic time tc=1.7 days, the velocity of propagation increases with decreasing concn. and above tc, the velocity increases with increasing concn. This latter behavior (above tc) completely reverses the field free trend. The effect of the field on the morphol. appearance of the bands is discussed.
    >> More from SciFinder ®
    https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD3cXovFemtb4%253D&md5=0ae9a62fac6cd55eb32de9b76eafaa02
  19. 19
    Badr, L.; Moussa, Z.; Hariri, A.; Sultan, R. Band, Target, and Onion Patterns in Co(OH)2 Liesegang Systems. Phys. Rev. E 2011, 83, 016109  DOI: 10.1103/PhysRevE.83.016109
    Google Scholar
    19
    Band, target, and onion patterns in Co(OH)2 Liesegang systems
    Badr, Layla; Moussa, Zeinab; Hariri, Amani; Sultan, Rabih
    Physical Review E: Statistical, Nonlinear, and Soft Matter Physics (2011), 83 (1-2), 016109/1-016109/6CODEN: PRESCM; ISSN:1539-3755. (American Physical Society)
    Liesegang expts. producing Co(OH)2 stratification were done, in one, two, and three dimensions for comparison of the pattern morphologies. The authors obtain well-resolved bands in one dimension, target patterns (rings) in two dimensions, and onion patterns (spherical shells) in three dimensions. The morphol. characteristics of the various patterns (spacing coeffs., rate of growth of ring spacing with distance) were measured. The spacing ratio of the strata in the different spatial dimensions was found to be anticorrelated with the surface-to-vol. ratio of the gel domain. Some studies featuring the importance of morphol. in Liesegang systems are briefly surveyed.
    >> More from SciFinder ®
    https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3MXhsFSgtrs%253D&md5=c0b473660629d793faa5ca0e06884c22
  20. 20
    Park, J. H.; Paczesny, J.; Kim, N.; Grzybowski, B. A. Shaping Microcrystals of Metal-Organic Frameworks by Reaction-Diffusion. Angew. Chem., Int. Ed. 2020, 59, 10301– 10305,  DOI: 10.1002/anie.201910989
    Google Scholar
    20
    Shaping Microcrystals of Metal-Organic Frameworks by Reaction-Diffusion
    Park, Jun Heuk; Paczesny, Jan; Kim, Namhun; Grzybowski, Bartosz A.
    Angewandte Chemie, International Edition (2020), 59 (26), 10301-10305CODEN: ACIEF5; ISSN:1433-7851. (Wiley-VCH Verlag GmbH & Co. KGaA)
    When components of a metal-org. framework (MOF) and a crystal growth modulator diffuse through a gel medium, they can form arrays of regularly-spaced pptn. bands contg. MOF crystals of different morphologies. With time, slow variations in the local concns. of the growth modulator cause the crystals to change their shapes, ultimately resulting in unusual concave microcrystallites not available via soln.-based methods. The reaction-diffusion and periodic pptn. phenomena (1) extend to various types of MOFs and also MOPs (metal-org. polyhedra), and (2) can be multiplexed to realize within one gel multiple growth conditions, in effect leading to various cryst. phases or polycryst. formations.
    >> More from SciFinder ®
    https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BB3cXntFGitLc%253D&md5=789a6419744fe3e6fb3310c65aa96d50
  21. 21
    Karam, T.; El-Rassy, H.; Sultan, R. Mechanism of Revert Spacing in a PbCrO4 Liesegang System. J. Phys. Chem. A 2011, 115, 2994– 2998,  DOI: 10.1021/jp200619g
    Google Scholar
    21
    Mechanism of Revert Spacing in a PbCrO4 Liesegang System
    Karam, Tony; El-Rassy, Houssam; Sultan, Rabih
    Journal of Physical Chemistry A (2011), 115 (14), 2994-2998CODEN: JPCAFH; ISSN:1089-5639. (American Chemical Society)
    Periodic pptn. of sparingly sol. salts yields parallel Liesegang bands in 1-dimensional whose spacings obey either one of two known trends. The overwhelming trend is an increase in spacing as the authors move away from the junction, while some systems display a decrease in spacing as the bands get further away from the interface. The latter trend is much less common and is known as the revert spacing law. Whereas the direct (normal) spacing law is generally well-undertsood, the revert spacing trend was not explicitly and distinctly elucidated. The authors propose a mechanism of revert spacing governed by the adsorption of the diffusing CrO42- ions on the formed PbCrO4 Liesegang bands and carry out a set of expts. that support the suggested scenario. This adsorption increases as the band no. (n) increases in revert spacing systems, while it decreases as n increases in direct spacing systems. This correlation in opposite directions decisively reveals the role of adsorption in the mechanism. The attraction between the CrO42- and Pb2+ in the gel causes the bands to form gradually closer and closer. Secondary structure (thinner bands formed within the main ones) obtained under some conditions is discussed in view of the light sensitivity of the chromate ion and the stability of the lead chromate sol.
    >> More from SciFinder ®
    https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3MXjvVaqu78%253D&md5=8b2e9dcf354bde3dd9e9b9e09f8d5e49
  22. 22
    Kalash, L.; Farah, H.; Eddin, A. Z.; Sultan, R. Dynamical Profiles of the Reactive Components in Direct and Revert Liesegang Patterns. Chem. Phys. Lett. 2013, 590, 69– 73,  DOI: 10.1016/j.cplett.2013.10.035
    Google Scholar
    22
    Dynamical profiles of the reactive components in direct and revert Liesegang patterns
    Kalash, Leen; Farah, Hiba; Eddin, Amal Zein; Sultan, Rabih
    Chemical Physics Letters (2013), 590 (), 69-73CODEN: CHPLBC; ISSN:0009-2614. (Elsevier B.V.)
    In periodic pptn. (Liesegang banding), the overwhelmingly common trend is the increase in spacing between consecutive bands as we move away from the interface. Revert spacing is a rare trend obsd. in a few systems, wherein the spacing decreases with distance from the interface. In this Letter, we compare the spatial profiles of the aq. components in two chromate Liesegang ppts.: CuCrO4 and PbCrO4, displaying direct and revert spacing, resp. The profiles are measured using UV-Vis spectrophotometry. The formation of a Pb2+-PbCrO4 complex in equil. with the free Pb2+, seems to play a key role in the revert spacing scenario.
    >> More from SciFinder ®
    https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3sXhslaitb%252FI&md5=6a735b17930ddbfda99a03a669704bd1
  23. 23
    Ezzeddine, D.; El-Rassy, H.; Sultan, R. Surface and Structural Studies in a PbCrO4 Liesegang Pattern with Revert Spacing. Chem. Phys. Lett. 2019, 734, 136735  DOI: 10.1016/j.cplett.2019.136735
    Google Scholar
    23
    Surface and structural studies in a PbCrO4 Liesegang pattern with revert spacing
    Ezzeddine, Dalia; El-Rassy, Houssam; Sultan, Rabih
    Chemical Physics Letters (2019), 734 (), 136735CODEN: CHPLBC; ISSN:0009-2614. (Elsevier B.V.)
    We present a novel study of a PbCrO4 Liesegang pattern exhibiting revert spacing. SEM, Atomic Absorption Spectrometry (AAS) and Energy Dispersive X-ray (EDX) spectroscopy measurements are carried out, and are shown to support the adsorption of CrO2-4 on the ppt., which becomes more enhanced as we move farther from the gel interface. Such an ascending differential adsorption scenario favors revert spacing over the direct spacing trend.
    >> More from SciFinder ®
    https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC1MXhslGmsLvL&md5=2ea53e3dbd933bac9380f0ed907d8caa
  24. 24
    Kanniah, N.; Gnanam, F. D.; Ramasamy, P.; Laddha, G. S. Revert and Direct Type Liesegang Phenomenon of Silver Iodide. J. Colloid Interface Sci. 1981, 80, 369– 376,  DOI: 10.1016/0021-9797(81)90195-8
    Google Scholar
    24
    Revert and direct type Liesegang phenomenon of silver iodide
    Kanniah, N.; Gnanam, F. D.; Ramasamy, P.; Laddha, G. S.
    Journal of Colloid and Interface Science (1981), 80 (2), 369-76CODEN: JCISA5; ISSN:0021-9797.
    The exptl. conditions for Liesegang phenomenon of AgI in agar gel columns, and particularly the transition from revert to direct type of periodic pptns., were studied. The theor. derived Mathur's spacing law, which suits both revert and direct type of Liesegang's rings, was verified exptl. An attempt is made to explain the mechanism of revert and direct type and of the transition of revert to direct type of periodic pptn. on the basis of adsorption on the pptd. AgI and of flocculation. The dependence of the transition point on the concns. of the outer and inner electrolytes was studied. The time law of Morse and Pierce is verified. The dependence of the rate const. (K = xn/tn1/2) on the concn. of the outer and inner electrolytes was studied.
    >> More from SciFinder ®
    https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaL3MXhs1eiur8%253D&md5=14f1063ab0db6eb96e55da52413a7636
  25. 25
    Kanniah, N.; Gnanam, F. D.; Ramasamy, P. Revert and Direct Liesegang Phenomenon of Silver Iodide: Factors Influencing the Transition Point. J. Colloid Interface Sci. 1983, 94, 412– 420,  DOI: 10.1016/0021-9797(83)90281-3
    Google Scholar
    25
    Revert and direct Liesegang phenomenon of silver iodide: factors influencing the transition point
    Kanniah, N.; Gnanam, F. D.; Ramasamy, P.
    Journal of Colloid and Interface Science (1983), 94 (2), 412-20CODEN: JCISA5; ISSN:0021-9797.
    A new theory based on the DLVO theory of stability of colloids was proposed to explain the mechanism of revert and direct Liesegang phenomenon and the transition of revert to direct type. This theory takes into account the surface potential, the zeta potential, the zero point of charge and the reversal of charge of the sol particles. The factors influencing the transition point are reported. The concn. and pH of the gel have a pronounced effect on the transition of revert to direct. The influence of different additives is discussed.
    >> More from SciFinder ®
    https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaL3sXksF2nsbw%253D&md5=bb225a7be385811718a5b33de426df51
  26. 26
    Kanniah, N.; Gnanam, F. D.; Ramasamy, P. A New Spacing Law for Liesegang Rings. Proc. - Indian Acad. Sci. 1984, 93, 801– 811,  DOI: 10.1007/BF02866341
    Google Scholar
    26
    A new spacing law for Liesegang rings
    Kanniah, N.; Gnanam, F. D.; Ramasamy, P.
    Proceedings - Indian Academy of Sciences, Chemical Sciences (1984), 93 (5), 801-11CODEN: PIAADM; ISSN:0253-4134.
    The spacing laws of Jablczynski (1923) and Mathut (1961) were applied to the Liesegang rings of Co(II) oxinate, AgI, and PbCrO4 in agar gel. Although Jablcynski's spacing law satisfactorily explains the direct Liesegang rings, it totally fails to describe the revert Liesegang rings. Similarly though Mathur's spacing law is applicable to both revert and direct type of periodic pptn., an appreciable deviation is obsd. in systems with greater interspacing. A new spacing law, applicable to both revert and direct Liesegang rings, is proposed on the basis of the preferential adsorption theory of Liesegang rings. It is verified exptl. with AgI and PbCrO4 systems.
    >> More from SciFinder ®
    https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaL2cXltFOns7w%253D&md5=d9b0b40f44089e41af094858b4a0f1b5
  27. 27
    Kulkarni, S. D.; Walimbe, P. C.; Ingulkar, R. B.; Lahase, J. D.; Kulkarni, P. S. Revert Banding in One-Dimensional Periodic Precipitation of the (AgNO3 + KBr) System in Agar Gel. ACS Omega 2019, 4, 13061– 13068,  DOI: 10.1021/acsomega.9b00937
    Google Scholar
    27
    Revert banding in one-dimensional periodic precipitation of (AgNO3 + KBr) system in agar gel
    Kulkarni, Sunil D.; Walimbe, Prasad C.; Ingulkar, Rohit B.; Lahase, Jagdish D.; Kulkarni, Preeti S.
    ACS Omega (2019), 4 (8), 13061-13068CODEN: ACSODF; ISSN:2470-1343. (American Chemical Society)
    A periodically pptg. system wherein interband distance successively decreases is known as revert Liesegang banding. The phenomenon is rare, and the underlying mechanism is implicit. In the present paper, the Liesegang system comprising of AgNO3 and KBr as the outer and inner electrolyte pair showing revert banding in agar gel by employing a 1D exptl. setup is studied under varying concns. of participating species. Revert banding was obsd. under all the exptl. conditions. The concns. of inner and outer electrolytes were found to play a major role in reverting since they build the ionic strength inside Liesegang tubes. We hypothesize that the band reverting is the interplay of van der Waals and elec. double-layer interactions, and hence classical DLVO (Derjaguin-Landau-Verwey-Overbeek) theory can be applied to interpret reverting. We propose that revert deposition of ppts. is the outcome of flocculation and peptization of sols, which is the manifestation of balancing attractive and repulsive interactions acting on colloidal particles responsible for band formation.
    >> More from SciFinder ®
    https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC1MXhsFWkt7zJ&md5=7f447015612bd2ef18ec7b37dd3da6f4
  28. 28
    Smoukov, S. K.; Lagzi, I.; Grzybowski, B. A. Independence of Primary and Secondary Structures in Periodic Precipitation Patterns. J. Phys. Chem. Lett. 2011, 2, 345– 349,  DOI: 10.1021/jz101679t
    Google Scholar
    28
    Independence of Primary and Secondary Structures in Periodic Precipitation Patterns
    Smoukov, Stoyan K.; Lagzi, Istvan; Grzybowski, Bartosz A.
    Journal of Physical Chemistry Letters (2011), 2 (4), 345-349CODEN: JPCLCD; ISSN:1948-7185. (American Chemical Society)
    Microscopic periodic pptn. patterns featuring both primary and secondary bands form in thin gel films. The initial conditions for the pptn. process are defined by wet stamping and are chosen such that the primary and secondary structures are not necessarily collinear; the fact that these structures propagate in different directions suggests that they form independently of one another. This hypothesis is further supported by a theor. model in which two different intermediate species mediate band formation.
    >> More from SciFinder ®
    https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3MXhtlCksr8%253D&md5=05fef5d70103b4a3500ad8f6df40f75b
  29. 29
    Tóth, R.; Walliser, R. M.; Lagzi, I.; Boudoire, F.; Duggelin, M.; Braun, A.; Housecroft, C. E.; Constable, E. C. Probing the Mystery of Liesegang Band Formation: Revealing the Origin of Self-organized Dual-frequency Micro and Nanoparticle Arrays. Soft Matter 2016, 12, 8367– 8374,  DOI: 10.1039/C6SM01564F
    Google Scholar
    29
    Probing the mystery of Liesegang band formation: revealing the origin of self-organized dual-frequency micro and nanoparticle arrays
    Toth, Rita; Walliser, Roche M.; Lagzi, Istvan; Boudoire, Florent; Duggelin, Marcel; Braun, Artur; Housecroft, Catherine E.; Constable, Edwin C.
    Soft Matter (2016), 12 (40), 8367-8374CODEN: SMOABF; ISSN:1744-683X. (Royal Society of Chemistry)
    Periodic pptn. processes in gels can result in impressive micro- and nanostructured patterns known as periodic pptn. (or Liesegang bands). Under certain conditions, the silver nitrate-chromium(VI) system exhibits the coexistence of two kinds of Liesegang bands with different frequencies. We now present that the two kinds of bands form independently on different time scales and the pH-dependent chromate(VI)-dichromate(VI) equil. controls the formation of the ppts. We detd. the spatial distribution and constitution of the particles in the bands using focused ion beam-SEM (FIB-SEM) and scanning transmission X-ray spectromicroscopy (STXM) measurements. This provided the necessary empirical input data to formulate a model for the pattern formation; a model that quant. reproduces the exptl. observations. Understanding the pattern-forming process at the mol. level enables us to tailor the size and the shape of the bands, which, in turn, can lead to new functional architectures for a range of applications.
    >> More from SciFinder ®
    https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC28XhsVKjurbI&md5=894ddf97187492262d714cafb3ffa76e
  30. 30
    Khan, M. T. A.; Kwiczak-Yiğitbaşı, J.; Tootoonchian, P.; Morsali, M.; Lagzi, I.; Baytekin, B. Chemical Tracking of Temperature by Concurrent Periodic Precipitation Pattern Formation in Polyacrylamide Gels. ACS Appl. Mater. Interfaces 2022, 14, 7252– 7260,  DOI: 10.1021/acsami.1c20640
    Google Scholar
    30
    Chemical Tracking of Temperature by Concurrent Periodic Precipitation Pattern Formation in Polyacrylamide Gels
    Khan, Muhammad Turab Ali; Kwiczak-Yigitbasi, Joanna; Tootoonchian, Pedram; Morsali, Mohammad; Lagzi, Istvan; Baytekin, Bilge
    ACS Applied Materials & Interfaces (2022), 14 (5), 7252-7260CODEN: AAMICK; ISSN:1944-8244. (American Chemical Society)
    In nature, nonequil. systems reflect environmental changes, and these changes are often "recorded" in their solid body as they develop. Periodic pptn. patterns, aka Liesegang patterns (LPs), are visual sums of complex events in nonequil. reaction-diffusion processes. Here we aim to achieve an artificial system that "records" the temp. changes in the environment with the concurrent LP formation. We first illustrate the differences in 1-D LPs developing at different temps. in terms of band spacings, which can demonstrate the time, ramp steepness, and extent of a temp. change. These results are discussed and augmented by a math. model. Using SEM, we show that the av. size of the CuCrO4 ppt. also reflects the temp. changes. Finally, we show that these changes can also be "recorded" in the 2-D and 3-D LPs, which can have applications in long-term temp. tracking and complex soft material design.
    >> More from SciFinder ®
    https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BB38Xhtl2htrc%253D&md5=2ba1658179a6847e06819a049e6057b9
  31. 31
    Lagzi, I.; Kármán, D. Equidistant Precipitate Pattern Formation Behind a Propagating Chemical Front. Chem. Phys. Lett. 2003, 372, 831– 835,  DOI: 10.1016/S0009-2614(03)00524-4
    Google Scholar
    31
    Equidistant precipitate pattern formation behind a propagating chemical front
    Lagzi, Istvan; Karman, Daniel
    Chemical Physics Letters (2003), 372 (5,6), 831-835CODEN: CHPLBC; ISSN:0009-2614. (Elsevier Science B.V.)
    Formation of one- and two-dimensional equidistant ppt. patterns due to the coupling of an autocatalytic chem. front with a pptn. reaction was studied numerically. A simple six-variable model based on a cubic autocatalytic reaction has been defined and investigated, where the pptn. step contained a diffusive intermediary species. Simulations show that such a hypothetical reaction-diffusion system can lead to formation of equidistantly striped or more complex patterns.
    >> More from SciFinder ®
    https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD3sXjsVeltro%253D&md5=467e8fe4cd229d69132d7fb9c10f2efb
  32. 32
    Bena, I.; Droz, M.; Lagzi, I.; Martens, K.; Rácz, Z.; Volford, A. Designed Patterns: Flexible Control of Precipitation through Electric Currents. Phys. Rev. Lett. 2008, 101, 075701  DOI: 10.1103/PhysRevLett.101.075701
    Google Scholar
    32
    Designed Patterns: Flexible Control of Precipitation through Electric Currents
    Bena, I.; Droz, M.; Lagzi, I.; Martens, K.; Racz, Z.; Volford, A.
    Physical Review Letters (2008), 101 (7), 075701/1-075701/4CODEN: PRLTAO; ISSN:0031-9007. (American Physical Society)
    Understanding and controlling pptn. patterns formed in reaction-diffusion processes is of fundamental importance with high potential for tech. applications. Here we present a theory showing that pptn. resulting from reactions among charged agents can be controlled by an appropriately designed, time-dependent elec. current. Examples of current dynamics yielding periodic bands of prescribed wavelength, as well as more complicated structures are given. The pattern control is demonstrated exptl. using the reaction-diffusion process 2AgNO3 + K2Cr2O7→Ag2Cr2O7 + 2KNO3.
    >> More from SciFinder ®
    https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD1cXhtVSisb%252FP&md5=c53dbedb22874b6de4df77abb7b7bc0f
  33. 33
    Dash, U. N. Solute–solvent Interactions and Dissolution of Some Sparingly Soluble Silver Salts in Various Solvent Systems. Fluid Phase Equilib. 1981, 5, 323– 336,  DOI: 10.1016/0378-3812(80)80064-1
    Google Scholar
    33
    Solute-solvent interactions and dissolution of some sparingly soluble silver salts in various solvent systems
    Dash, Upendra N.
    Fluid Phase Equilibria (1981), 5 (3-4), 323-36CODEN: FPEQDT; ISSN:0378-3812.
    The values for the soly. products of Ag salts in aq., non-aq., and mixed solvent systems were collected and analyzed in the light of electrostatic as well as solute-solvent interaction effects on the dissoln. processes of Ag salts. Std. Gibbs transfer energies derived from the change in the soly. product value were also examd. Solute-solvent interactions rather than electrostatic effects assocd. with the change in dielec. const. are largely responsible for the changes in the value of soly. product with the compn. of the solvent mixts.
    >> More from SciFinder ®
    https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaL3MXptFalsA%253D%253D&md5=b63c31ac60266674b70ceed66e66e14b
  34. 34
    Dash, U. N.; Pattanaik, E.; Sahu, R. Solute-solvent Interactions: Dissolution of Sparingly Soluble Silver Salts in Aqueous-organic Solvent Systems. Fluid Phase Equilib. 1991, 63, 101– 110,  DOI: 10.1016/0378-3812(91)80023-O
    Google Scholar
    34
    Solute-solvent interactions: dissolution of sparingly soluble silver salts in aqueous-organic solvent systems
    Dash, Upendra; Pattanaik, Ellarani; Sahu, Renuka
    Fluid Phase Equilibria (1991), 63 (1-2), 101-10CODEN: FPEQDT; ISSN:0378-3812.
    The solubilities of the salts Ag2X (where X is sulfate, chromate, tungstate, dichromate, oxalate, malonate, succinate, glutarate or adipate) and Ag,Y (where Y is phosphate or arsenate) were detd. in various compns. of water + dioxane (5-20 wt.%), water + urea (11.52-36.83 wt.%), water + mannitol (5 wt.%) and water + sorbitol (5 wt.%) mixts. at different temps. The soly. data are discussed in the light of electrostatic as well as solute-solvent interaction effects on the dissoln. processes of the silver salts. Std. transfer thermodn. quantities derived from the change in the soly. product are also examd.
    >> More from SciFinder ®
    https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaK3MXktlKmsr0%253D&md5=c14fb2493f78cc2a5e0e9ef754af4aaf
  35. 35
    Humayun, H. Y.; Shaarani, M. N. N. M.; warrior, A.; Abdullah, B.; Salam, M. A. The Effect of Co-solvent on the Solubility of a Sparingly Soluble Crystal of Benzoic Acid. Procedia Eng. 2016, 148, 1320– 1325,  DOI: 10.1016/j.proeng.2016.06.548
    Google Scholar
    35
    The Effect of Co-solvent on the Solubility of a Sparingly Soluble Crystal of Benzoic Acid
    Humayun, Hudzaifah Yousuf; Shaarani, M. Nizamuddin N. M.; Warrior, Ali; Abdullah, Bawadi; Salam, Md. Abdus
    Procedia Engineering (2016), 148 (), 1320-1325CODEN: PERNBE; ISSN:1877-7058. (Elsevier Ltd.)
    The Benzoic acid is widely used in the pharmaceutical industry, plasticizers and food preservative which show low aq. soly. and dissoln. rate. The investigation has been made to improve the soly. of benzoic acid by using co-solvent. The co-solvent soln. is prepd. by using glycerol in water by vol. ratio. The result shows the relation between soly. in different co-solvent and temp. whereby as the percentage of glycerol increase, the soly. of benzoic acid increase. A similartrend was depicted in term of soly. relation with temp. as the temp. increase amt. of benzoic acid dissolved also increase. Thermodn. dissocn. const., pKa are directly proportional totemperature between 30oC and 90oC. Enthalpy and entropy change of the dissocn. process are 2.907 kJ/mol and -24.09 J/mol resp. Gibbs free energy of dissocn. at 30oC, 60oC and 90oC are -4.390 KJ/mol, -5.114 KJ/mol and 5.837 KJ/mol resp. depicted that the soly. increased with temp.
    >> More from SciFinder ®
    https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC28Xht1Siu73P&md5=09f53b4110b2db58d50b425a583d9a9c
  36. 36
    Dembek, M.; Bocian, S.; Buszewski, B. Solvent Influence on Zeta Potential of Stationary Phase─Mobile Phase Interface. Molecules 2022, 27, 968  DOI: 10.3390/molecules27030968
    Google Scholar
    36
    Solvent Influence on Zeta Potential of Stationary Phase-Mobile Phase Interface
    Dembek, Mikolaj; Bocian, Szymon; Buszewski, Boguslaw
    Molecules (2022), 27 (3), 968CODEN: MOLEFW; ISSN:1420-3049. (MDPI AG)
    Zeta potential is a surface characteristic formed on the solid surface and liq. interface. It is an interesting way to describe the surface properties of materials; thus, a series of four homemade polar embedded stationary phases that contain phosphate groups incorporated into hydrophobic ligands were investigated according to surface zeta potential. Measurements were carried out using Zetasizer Nano ZS for the stationary phases suspensions prepd. in various solvent and solvent binary mixts. The neg. zeta potential values were obtained for most cases due to neg. charged residual silanols and phosphate groups. However, in some solvents: THF, isopropanol, and toluene zeta potential are pos. Addnl., it was obsd. that the zeta potential seems to be independent of the type of silica gel used for the stationary phase synthesis.
    >> More from SciFinder ®
    https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BB38XktFahtLY%253D&md5=2be4b7787a82037cfb3c4528e32df6a7
  37. 37
    Lyklema, J. Principles of the Stability of lyophobic Colloidal Dispersions in Non-aqueous Media. Adv. Colloid Interface Sci. 1968, 2, 67– 114,  DOI: 10.1016/0001-8686(68)85001-8
    Google Scholar
    There is no corresponding record for this reference.
  38. 38
    Płowaś, I.; Świergiel, J.; Jadżyn, J. Relative Static Permittivity of Dimethyl Sulfoxide + Water Mixtures. J. Chem. Eng. Data 2013, 58, 1741– 1746,  DOI: 10.1021/je400149j
    Google Scholar
    38
    Relative Static Permittivity of Dimethyl Sulfoxide + Water Mixtures
    Plowas, Iwona; Swiergiel, Jolanta; Jadzyn, Jan
    Journal of Chemical & Engineering Data (2013), 58 (6), 1741-1746CODEN: JCEAAX; ISSN:0021-9568. (American Chemical Society)
    The dielec. spectra corresponding to the static regime of DMSO + water mixts. were recorded in the whole concn. range and in the temp. range from (253.15 to 333.15) K. For the mixts. rich in DMSO (0.60 < xDMSO ≤ 1, x = mole fraction) and rich in water (0 ≤ xDMSO < 0.1), it was possible to perform the investigations both in the liq. and solid phases of the samples. The detd. melting temps. were compared to the data available in the literature. The deviation from the additivity of the measured static permittivity of DMSO + water mixts. shows a max. for xDMSO ≈ 0.35, indicating formation at that concn. of intermol. entities (most probably they are 1DMSO·2H2O hydrogen-bonded complexes) of a relatively enhanced polarity.
    >> More from SciFinder ®
    https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3sXnvVCqu78%253D&md5=21109d4578e5b052d8b285676c7fe7bd
  39. 39
    Dee, G. T. Patterns Produced by Precipitation at a Moving Reaction Front. Phys. Rev. Lett. 1986, 57, 275– 278,  DOI: 10.1103/PhysRevLett.57.275
    Google Scholar
    39
    Patterns produced by precipitation at a moving reaction front
    Dee, G. T.
    Physical Review Letters (1986), 57 (3), 275-8CODEN: PRLTAO; ISSN:0031-9007.
    Many pptn. patterns are assocd. with the formation of a sparingly sol. product at a moving reaction front. A model is introduced which describes the transport, reaction, nucleation, and droplet-growth kinetics of the processes involved. The rapid change in the nucleation rate as a function of the supersatn. is essential for pattern formation. The model allows the correlation details of the patterns with the various kinetic processes.
    >> More from SciFinder ®
    https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaL28XkvVGrt7g%253D&md5=760a5f33ad36090cbc0c9fd28462b8f9
  40. 40
    Krug, H.-J.; Brandtstädter, H. Morphological Characteristics of Liesegang Rings and Their Simulations. J. Phys. Chem. A 1999, 103, 7811– 7820,  DOI: 10.1021/jp991092l
    Google Scholar
    40
    Morphological Characteristics of Liesegang Rings and Their Simulations
    Krug, Hans-Juergen; Brandtstaedter, Hermann
    Journal of Physical Chemistry A (1999), 103 (39), 7811-7820CODEN: JPCAFH; ISSN:1089-5639. (American Chemical Society)
    Numerical simulations of Liesegang systems are performed both with a prenucleation and a postnucleation model. Special interest is dedicated to 2-dimensional morphol. peculiarities of ring systems. With the prenucleation model, apparent bifurcations or branch points (anastomoses) can be created by adjacent trains of bands having different interband spaces or band positions shifted to each other. Spiral systems arise when the circular symmetry of concentric Liesegang rings is broken by at least one branch point. The postnucleation model comprises both formation of colloidal particles which form a turbidity zone and transition of these nuclei to solid particles which undergo Ostwald ripening at the expense of the colloids. The model demonstrates how Liesegang bands of solid particles arise from a primary turbidity zone which surrounds the expanding ring system. Because of rapid competitive particle growth, rings or bands may no longer grow continuously in transversal directions. They become arranged in chains of single filaments or spots forming a transversal rhythm. Finally, longitudinal alleys of gaps appear in continuous trains of Liesegang bands.
    >> More from SciFinder ®
    https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaK1MXlslOntLY%253D&md5=8c4bf9b11c817ac61fd270e94be99435
  41. 41
    Pan, C.; Gao, Q.; Xie, J.; Xia, Y.; Epstein, I. R. Precipitation Patterns with Polygonal Boundaries Between Electrolytes. Phys. Chem. Chem. Phys. 2009, 11, 11033– 11039,  DOI: 10.1039/b904445k
    Google Scholar
    41
    Precipitation patterns with polygonal boundaries between electrolytes
    Pan, Changwei; Gao, Qingyu; Xie, Jingxuan; Xia, Yu; Epstein, Irving R.
    Physical Chemistry Chemical Physics (2009), 11 (46), 11033-11039CODEN: PPCPFQ; ISSN:1463-9076. (Royal Society of Chemistry)
    Two-dimensional Liesegang patterns formed when the boundary between electrolytes is polygonal display a variety of patterns, such as dislocations (radial alleys of gaps), branches (anastomoses) and spirals, many of which can be found in nature. Each vertex of the polygon can produce a pair of dislocation lines or branch lines. The effect caused by a vertex decreases with the no. of vertices. Double-armed spirals are obsd. in expts. with a pentagonal boundary. Hexagons, which begin to approach smooth circular boundaries, do not give rise to dislocations, but instead yield concentric pptn. rings. A simple model of nucleation growth enables us to simulate dislocations and spirals consistent with those seen in our expts.
    >> More from SciFinder ®
    https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD1MXhsVentrfJ&md5=bd2b666249589e4d449b273dfa36ea68
  42. 42
    Kumbharkhane, A. C.; Puranik, S. M.; Mehrotra, S. C. Dielectric Relaxation Studies of Aqueous N,N-dimethylformamide Using a Picosecond Time Domain Technique. J. Solution Chem. 1993, 22, 219– 229,  DOI: 10.1007/BF00649245
    Google Scholar
    42
    Dielectric relaxation studies of aqueous N,N-dimethylformamide using a picosecond time domain technique
    Kumbharkhane, A. C.; Puranik, S. M.; Mehrotra, S. C.
    Journal of Solution Chemistry (1993), 22 (3), 219-29CODEN: JSLCAG; ISSN:0095-9782.
    The dielec. relaxation studies of DMF at 13 concn. in aq. solns. were carried out by using a time-domain reflectometry technique in the frequency range from 10 MHz to 10 GHz. The dielec. parameters and excess dielec. properties also were detd. at 5-40°. The Luzar theory was applied to compute the cross correlation terms for the mixt. It adequately reproduces the exptl. values of the static dielec. consts. The Bruggeman model for the nonlinear case was fitted to the dielec. data for mixts.
    >> More from SciFinder ®
    https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaK3sXitVehs78%253D&md5=942800a9fd62143a47a637d4dc65b020
  43. 43
    Zahn, M.; Ohki, Y.; Fenneman, D. B.; Gripshover, R. J.; Gehman, V. H. Dielectric Properties of Water and Water/ethylene Glycol Mixtures for Use in Pulsed Power System Design. Proc. IEEE 1986, 74, 1182– 1221,  DOI: 10.1109/PROC.1986.13611
    Google Scholar
    43
    Dielectric properties of water and water/ethylene glycol mixtures for use in pulsed power system design
    Zahn, Markus; Ohki, Yoshimichi; Fenneman, David B.; Gripshover, Ronald J.; Gehman, Victor H., Jr.
    Proceedings of the IEEE (1986), 74 (9), 1182-221CODEN: IEEPAD; ISSN:0018-9219.
    A review with 176 refs. with emphasis on dielec. const., breakdown strength, and relaxation time.
    >> More from SciFinder ®
    https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaL28XmtVWisL8%253D&md5=a7369b346d3d17aeb4759259d7d10ab4
  44. 44
    Kumbharkhane, A. C.; Puranik, S. M.; Mehrotra, S. C. Dielectric Relaxation of Tert-butyl Alcohol–water Mixtures Using a Time-domain Technique. J. Chem. Soc., Faraday Trans. 1991, 87, 1569– 1573,  DOI: 10.1039/FT9918701569
    Google Scholar
    44
    Dielectric relaxation of tert-butyl alcohol-water mixtures using a time-domain technique
    Kumbharkhane, Ashok C.; Puranik, Sanjay M.; Mehrotra, Suresh C.
    Journal of the Chemical Society, Faraday Transactions (1991), 87 (10), 1569-73CODEN: JCFTEV; ISSN:0956-5000.
    Dielec. relaxation measurements in the frequency range 10 MHz-10 GHz have been carried out in tert-Bu alc.-water mixts. with various concns. over the temp. range 273-313 K using a time-domain reflectometry (TDR) method. The bilinear calibration method as suggested by Cole has been used to correct the permittivity spectra. The cor. spectra could be fitted with a single relaxation time with a small amt. of Cole-Davidson behavior. Deviations from ideal mixing behavior in the permittivity parameter (ε0-ε∞) and relaxation time (τ) suggested the formation of a polymeric structure in tert-Bu alc.-water mixts. The dielec. relaxation behavior showed the same structural changes as obsd. in ultrasonic relaxation. However, the max. in excess permittivity and excess relation time occurred at different positions. This could not be explained by a simple model of the polymeric structure.
    >> More from SciFinder ®
    https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaK3MXktl2rtL4%253D&md5=ee610aa2fdb9df46c67d02ada7973c2a
  45. 45
    Sonnati, M. O.; Amigoni, S.; Taffin de Givenchy, E. P.; Darmanin, T.; Choulet, O.; Guittard, F. Glycerol Carbonate as a Versatile Building Block for Tomorrow: Synthesis, Reactivity, Properties and Applications. Green Chem. 2013, 15, 283– 306,  DOI: 10.1039/C2GC36525A
    Google Scholar
    45
    Glycerol carbonate as a versatile building block for tomorrow: synthesis, reactivity, properties and applications
    Sonnati, Matthieu O.; Amigoni, Sonia; Taffin de Givenchy, Elisabeth P.; Darmanin, Thierry; Choulet, Olivier; Guittard, Frederic
    Green Chemistry (2013), 15 (2), 283-306CODEN: GRCHFJ; ISSN:1463-9262. (Royal Society of Chemistry)
    A review. The synthesis, reactivity and applications of glycerol carbonate (glycerin carbonate or 4-hydroxymethyl-2-oxo-1,3-dioxolane) are discussed and reviewed. Supported by the increasing sustainable awareness, glycerol carbonate has gained much interest over the last 20 years because of its versatile reactivity and as a way to valorize waste glycerol. Numerous synthesis pathways for this mol. were identified, some of them very promising and on the verge of being applied at an industrial scale. The wide reactivity of this mol. due to the presence of both a hydroxyl group and a 2-oxo-1,3-dioxolane group has been studied and has initiated some emerging applications in various domains from solvents to polymers.
    >> More from SciFinder ®
    https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3sXhsVOnt7c%253D&md5=5d6f8a923217cb4507843afa7e5ce35a
  46. 46
    Sarri, F.; Tatini, D.; Tanini, D.; Simonelli, M.; Ambrosi, M.; Ninham, B. W.; Capperucci, A.; Dei, L.; Lo Nostro, P. Specific Ion Effects in Non-aqueous Solvents: the Case of Glycerol Carbonate. J. Mol. Liq. 2018, 266, 711– 717,  DOI: 10.1016/j.molliq.2018.06.120
    Google Scholar
    46
    Specific ion effects in non-aqueous solvents: The case of glycerol carbonate
    Sarri, Filippo; Tatini, Duccio; Tanini, Damiano; Simonelli, Matteo; Ambrosi, Moira; Ninham, Barry W.; Capperucci, Antonella; Dei, Luigi; Lo Nostro, Pierandrea
    Journal of Molecular Liquids (2018), 266 (), 711-717CODEN: JMLIDT; ISSN:0167-7322. (Elsevier B.V.)
    The effect of eight potassium salts (KF, K3PO4, KOCN, K2CO3, KCl, K2SO4, KBr and KI) on glycerol carbonate (GC) is studied through NMR, DSC, soly. and ATR-FTIR expts. From the soly. data, the main thermodn. functions of soln. and solvation are estd., and the mean molal activity coeffs. are calcd. The results suggest that the capability of an anion to establish hydrogen bonds with the solvent mols. (or behave as a base, as in the case of fluoride, phosphate, cyanate and carbonate) is the most important structural feature that dets. its effects on the solvent structure. On the other hand potassium iodide behaves in an anomalous way, due to the large polarizability of the anion that can form non-electrostatic, van der Waals dispersive intermol. interactions.
    >> More from SciFinder ®
    https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC1cXht12ju7vI&md5=e849a4fca7bf75bf742d8cb7a390dc5f
  47. 47
    Valletti, N.; Acar, M.; Cucciniello, R.; Magrini, C.; Budroni, M. A.; Tatini, D.; Proto, A.; Marchettini, N.; Lo Nostro, P.; Rossi, F. Glycerol Carbonate Structuring in Aqueous Solutions as Inferred from Mutual Diffusion Coefficient, Density and Viscosity Measurements in the Temperature Range 283.15–313.15 K. J. Mol. Liq. 2022, 357, 119114  DOI: 10.1016/j.molliq.2022.119114
    Google Scholar
    47
    Glycerol carbonate structuring in aqueous solutions as inferred from mutual diffusion coefficient, density and viscosity measurements in the temperature range 283.15-313.15 K
    Valletti, Nadia; Acar, Mert; Cucciniello, Raffaele; Magrini, Claudia; Budroni, Marcello A.; Tatini, Duccio; Proto, Antonio; Marchettini, Nadia; Lo Nostro, Pierandrea; Rossi, Federico
    Journal of Molecular Liquids (2022), 357 (), 119114CODEN: JMLIDT; ISSN:0167-7322. (Elsevier B.V.)
    Glycerol Carbonate (4-hydroxymethyl-2-oxo-1,3-dioxolane, GC) is an emerging green reactant for many org. chem. applications. GC popularity stems from its high reactivity, which makes it attractive for many chem. transformations and for its easy synthesis from glycerol, a byproduct of biodiesel prodn. While extensive literature covers the synthesis and chem. reactivity of GC, its transport properties are poorly studied, esp. in water. Here, we measured for the first time the diffusion coeff. of GC in water in the temp. range 283.15-313.15 K and for concns. up to 0.1 M. By taking advantage of the Taylor Dispersion Anal. (TDA) we found D0 = 9.53±0.06 x 10-10 m2/s at 298.15 K and an activation energy for the diffusion process Ea = 3.74±0.09 kcal/mol. D. and dynamic viscosity were also measured in the same temp. interval to calc. the hydrodynamic radius of GC. Exptl. data helped in assessing the structure of GC aggregates formed in aq. solns. and provided an estn. of the equil. const. for the dimer formation. Our findings can be useful for studying the fate of GC in the environment and to improve its use for applications in aq. media.
    >> More from SciFinder ®
    https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BB38XhtValu7%252FM&md5=62347cb3d2d851927657db42a3f1f1f0
  48. 48
    Droz, M.; Magnin, J.; Zrinyi, M. Liesegang Patterns: Studies on the Width Law. Chem. Phys. 1999, 110, 9618– 9622,  DOI: 10.1063/1.478927
    Google Scholar
    48
    Liesegang patterns: Studies on the width law
    Droz, M.; Magnin, J.; Zrinyi, M.
    Journal of Chemical Physics (1999), 110 (19), 9618-9622CODEN: JCPSA6; ISSN:0021-9606. (American Institute of Physics)
    The so-called width law for Liesegang patterns, which states that the positions xn and widths wn of bands verify the relation xn∼wnα for some α>0, is investigated both exptl. and theor. We provide exptl. data exhibiting good evidence for values of α close to 1. The value α=1 is supported by theor. arguments based on a generic model of reaction diffusion.
    >> More from SciFinder ®
    https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaK1MXislOju7Y%253D&md5=0f0082741a49c1afd087425c31cbf74c
  49. 49
    Rácz, Z. Formation of Liesegang Patterns. Phys. A 1999, 274, 50– 59,  DOI: 10.1016/S0378-4371(99)00432-X
    Google Scholar
    49
    Formation of Liesegang patterns
    Racz, Zoltan
    Physica A: Statistical Mechanics and Its Applications (Amsterdam) (1999), 274 (1-2), 50-59CODEN: PHYADX; ISSN:0378-4371. (Elsevier Science B.V.)
    It has been recently shown that pptn. bands characteristic of Liesegang patterns emerge from spinodal decompn. of reaction products in the wake of moving reaction fronts. This mechanism explains the geometric sequence of band positions xn ∼ Q(1 + p)n and, furthermore, it yields a spacing coeff. p that is in agreement with the exptl. obsd. Matalon-Packter law. Here I examine the assumptions underlying this theory and discuss the choice of input parameters that leads to exptl. observable patterns. I also show that the so-called width law relating the position and the width of the bands wn ∼ xn follows naturally from this theory.
    >> More from SciFinder ®
    https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD3cXnt1Cksg%253D%253D&md5=c1adaa1530961dfdb957cfa23a93fb22
  50. 50
    Israelachvili, J. N. Intermolecular and Surface Forces; Academic Press: Cambridge, Massachusetts, United States, 2011.
    Google Scholar
    There is no corresponding record for this reference.
  51. 51
    Nabika, H.; Sato, M.; Unoura, K. Liesegang Patterns Engineered by a Chemical Reaction Assisted by Complex Formation. Langmuir 2014, 30, 5047– 5051,  DOI: 10.1021/la5003786
    Google Scholar
    51
    Liesegang Patterns Engineered by a Chemical Reaction Assisted by Complex Formation
    Nabika, Hideki; Sato, Mami; Unoura, Kei
    Langmuir (2014), 30 (18), 5047-5051CODEN: LANGD5; ISSN:0743-7463. (American Chemical Society)
    Liesegang rings based on a chem. reaction, not a conventional pptn. reaction, have been developed by appropriate design of the nucleation dynamics in a system involving complex formation in a matrix. The periodic and concentric rings consisted of well-dispersed Ag nanoparticles with diams. of a few nanometers. The approach modeled here could be applied to form novel micropatterns out of inorg. salts, metal nanoparticles, org. nanocrystals, or polymeric fibers, and it could also offer a scaffold for novel models of a wide variety of reaction-diffusion phenomena in nature.
    >> More from SciFinder ®
    https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2cXmvFequrc%253D&md5=66d5ada9ac5ccc1ce509933172561443
  52. 52
    Walliser, R. M.; Boudoire, F.; Orosz, E.; Tóth, R.; Braun, A.; Constable, E. C.; Rácz, Z.; Lagzi, I. Growth of Nanoparticles and Microparticles by Controlled Reaction-diffusion Processes. Langmuir 2015, 31, 1828– 1834,  DOI: 10.1021/la504123k
    Google Scholar
    52
    Growth of Nanoparticles and Microparticles by Controlled Reaction-Diffusion Processes
    Walliser, Roche M.; Boudoire, Florent; Orosz, Eszter; Toth, Rita; Braun, Artur; Constable, Edwin C.; Racz, Zoltan; Lagzi, Istvan
    Langmuir (2015), 31 (5), 1828-1834CODEN: LANGD5; ISSN:0743-7463. (American Chemical Society)
    The synthesis of different sizes of nanoparticles and microparticles is important in designing nanostructured materials with various properties. Wet synthesis methods lack the flexibility to create various sizes of particles (particle libraries) using fixed conditions without the repetition of the steps in the method with a new set of parameters. Here, the authors report a synthesis method based on nucleation and particle growth in the wake of a moving chem. front in a gel matrix. The process yields well-sepd. regions (bands) filled with nearly monodisperse nanoparticles and microparticles, with the size of the particles varying from band to band in a predictable way. The origin of the effect is due to an interplay of a pptn. reaction of the reagents and their diffusion that is controlled in space and time by the moving chem. front. The method represents a new approach and a promising tool for the fast and competitive synthesis of various sizes of colloidal particles.
    >> More from SciFinder ®
    https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2MXmvFSjsw%253D%253D&md5=8d3e7be0888082a7b1a83dfeb7eee97c
  53. 53
    Moncure, P. J.; Simon, Z. C.; Millstone, J. E.; Laaser, J. E. Relationship between Gel Mesh and Particle Size in Determining Nanoparticle Diffusion in Hydrogel Nanocomposites. J. Phys. Chem. B 2022, 126, 4132– 4142,  DOI: 10.1021/acs.jpcb.2c00771
    Google Scholar
    53
    Relationship between Gel Mesh and Particle Size in Determining Nanoparticle Diffusion in Hydrogel Nanocomposites
    Moncure, Paige J.; Simon, Zoe C.; Millstone, Jill E.; Laaser, Jennifer E.
    Journal of Physical Chemistry B (2022), 126 (22), 4132-4142CODEN: JPCBFK; ISSN:1520-5207. (American Chemical Society)
    The diffusion of poly(ethylene glycol) Me ether thiol (PEGSH)-functionalized gold nanoparticles (NPs) was measured in polyacrylamide gels with various crosslinking densities. The mol. wt. of the PEGSH ligand and particle core size were both varied to yield particles with hydrodynamic diams. ranging from 7 to 21 nm. The gel mesh size was varied from approx. 36 to 60 nm by controlling the crosslinking d. of the gel. Because high-mol.-wt. ligands are expected to yield more compressible particles, we expected the diffusion consts. of the NPs to depend on their hard/soft ratios (where the hard component of the particle consists of the particle core and the soft component of the particle consists of the ligand shell). However, our measurements revealed that NP diffusion coeffs. resulted primarily from changes in the overall hydrodynamic diam. and not the ratio of particle core size to ligand size. Across all particles and gels, we found that the diffusion coeff. was well predicted by the confinement ratio calcd. from the diam. of the particle and an est. of the gel mesh size obtained from the elastic blob model and was well described using a hopping model for nanoparticle diffusion. These results suggest that the elastic blob model provides a reasonable est. of the mesh size that particles "see" as they diffuse through the gel. This work brings new insights into the factors that dictate how NPs move through polymer gels and will inform the development of hydrogel nanocomposites for applications such as drug delivery in heterogeneous, viscoelastic biol. materials.
    >> More from SciFinder ®
    https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BB38XhtlCmt7bO&md5=2efe23e7cf35d7340941fe18f90389e5
  54. 54
    Jiang, J.; Sakurai, K. Formation of Ultrathin Liesegang Patterns. Langmuir 2016, 32, 9126– 9134,  DOI: 10.1021/acs.langmuir.6b02148
    Google Scholar
    54
    Formation of Ultrathin Liesegang Patterns
    Jiang, Jinxing; Sakurai, Kenji
    Langmuir (2016), 32 (36), 9126-9134CODEN: LANGD5; ISSN:0743-7463. (American Chemical Society)
    Liesegang patterns (LPs) have been prepd. in nanofilms 65 nm thick. The key parameters are temp. control and the introduction of equil. water vapor in the sample environment. Atomic force microscope images clearly showed that the LPs are composed of 300-600 nm laterally coagulated particles. The densities and thicknesses of the ultrathin films were evaluated by X-ray reflectivity. During the present research, new patterns, which are different from ordinary LPs, have been discovered for the first time in the outermost part of the whole pattern. Studying LPs in ultrathin films may help to forge a better understanding of the mechanism underlying the intriguing phenomenon.
    >> More from SciFinder ®
    https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC28XhtlajtrzF&md5=b96f4b2b1317b35ade9722ca407fbde5
  55. 55
    Farkas, S.; Fonyi, M. S.; Holló, G.; Német, N.; Valletti, N.; Kukovecz, Á.; Schuszter, G.; Rossi, F.; Lagzi, I. Periodic Precipitation of Zeolitic Imidazolate Frameworks in a Gelled Medium. J. Phys. Chem. C 2022, 126, 9580– 9586,  DOI: 10.1021/acs.jpcc.2c02371
    Google Scholar
    55
    Periodic Precipitation of Zeolitic Imidazolate Frameworks in a Gelled Medium
    Farkas, Szabolcs; Fonyi, Mate Sandor; Hollo, Gabor; Nemet, Norbert; Valletti, Nadia; Kukovecz, Akos; Schuszter, Gabor; Rossi, Federico; Lagzi, Istvan
    Journal of Physical Chemistry C (2022), 126 (22), 9580-9586CODEN: JPCCCK; ISSN:1932-7447. (American Chemical Society)
    Formation of spatially periodic patterns is a ubiquitous process in nature and man-made systems. Periodic pptn. is the oldest type of pattern formation, in which the formed colloid particles are self-assembled into a sequence of spatially sepd. pptn. zones in solid hydrogels. Chem. systems exhibiting periodic pptn. mostly comprise oppositely charged inorg. ions. Here, we present a new sub-group of this phenomenon driven by the diffusion and reaction of several transition metal cations (Zn2+, Co2+, Cd2+, Cu2+, Fe2+, Mn2+, and Ni2+) with an org. linker (2-methylimidazole) producing periodic pptn. of zeolitic imidazolate frameworks. In some cases, the formed crystals reached the size of ∼50μm showing that a gel matrix can provide optimal conditions for nucleation and crystal growth. We investigated the effect of the gel concn. and solvent compn. on the morphol. of the pattern. To support the exptl. observations, we developed a reaction-diffusion model, which qual. describes the spatially periodic pattern formation.
    >> More from SciFinder ®
    https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BB38XhtlCmtLzF&md5=660693f7af88f633d7ae61fc85f70bb5

Cited By

Click to copy section linkSection link copied!

This article is cited by 3 publications.

  1. Masaki Itatani, Yuhei Onishi, Nobuhiko J. Suematsu, István Lagzi. Periodic Precipitation in a Confined Liquid Layer. The Journal of Physical Chemistry Letters 2024, 15 (18) , 4948-4957. https://doi.org/10.1021/acs.jpclett.4c00832
  2. Elif Sila Akbulut, Gábor Holló, Istvan Lagzi, Bilge Baytekin. Complex Patterning of Matter with Liesegang Patterns Propagating through Different Concentration Media─Gel Lenses for Liesegang Waves. Crystal Growth & Design 2023, 23 (12) , 8718-8725. https://doi.org/10.1021/acs.cgd.3c00871
  3. Masaki Itatani, Norbert Német, Nadia Valletti, Gábor Schuszter, Prisco Prete, Pierandrea Lo Nostro, Raffaele Cucciniello, Federico Rossi, István Lagzi. Synthesis of Zeolitic Imidazolate Framework-8 Using Glycerol Carbonate. ACS Sustainable Chemistry & Engineering 2023, 11 (35) , 13043-13049. https://doi.org/10.1021/acssuschemeng.3c02876
Download PDF
Open PDF
Go to The Journal of Physical Chemistry B
Get e-Alerts
Get e-Alerts

The Journal of Physical Chemistry B

Cite this: J. Phys. Chem. B 2022, 126, 41, 8322–8330
Click to copy citationCitation copied!
https://doi.org/10.1021/acs.jpcb.2c05810
Published October 11, 2022

Copyright © 2022 The Authors. Published by American Chemical Society. This publication is licensed under

CC-BY 4.0 .

Article Views

1889

Altmetric

-

Citations

3
Learn about these metrics

Article Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.

Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.

The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated.

  • Abstract

    High Resolution Image
    Download MS PowerPoint Slide

    Figure 1

    Figure 1. (a) Pattern formation of the CuCrO4 system using different volume ratios of DMSO (φDMSO) ranging from φDMSO = 0 (pure water) to φDMSO = 0.5 (water:DMSO = 50%:50%). (b) Enlarged optical photographs of regions (i)–(iii) in (a).

    High Resolution Image
    Download MS PowerPoint Slide

    Figure 2

    Figure 2. (a) Line profile analysis of the LPs starting from the liquid–gel interface (position = 0) to the bottom of test tubes at various DMSO contents. (b) Enlarged views of the regions (i) and (ii) are indicated as dotted line squares in (a). (c) Relationship between the spacing coefficient (p) and φDMSO. The plot was fitted by a power function (f(x) = f(0) + αxβ, where α and β are coefficients). Error bars were obtained from 5 replicates, which were calculated using p-values < 0.05.

    High Resolution Image
    Download MS PowerPoint Slide

    Figure 3

    Figure 3. (a) Size distribution of CuCrO4 colloidal particles in aqueous solution with different φDMSO, measured by dynamic light scattering (DLS). (b) Relationship between the mean particle size at the 1st peak (with a smaller size in bimodal distribution) and φDMSO. (c) Relationship between the ζ potential of CuCrO4 particles and φDMSO. Error bars were obtained from 3 replicates, which were calculated using p-values < 0.05.

    High Resolution Image
    Download MS PowerPoint Slide

    Figure 4

    Figure 4. (a) Effect of φ on the pattern structure in simulations (φDMSO in experiments), where φ = 0 and 0.5 correspond to conditions of pure water and water/DMSO mixture of 1:1. Color changes from green to yellow show the sum of concentrations (e + g) of species E and G. (b) Concentration profiles of E + G in simulations at various φ. Regions surrounded by the dotted line square at φ = 0.3–0.5 are inserted into the right panel of each condition as enlarged graphs. Gray regions in enlarged graphs correspond to the formation of the low-frequency revert patterns.

    High Resolution Image
    Download MS PowerPoint Slide

  • References

    This article references 55 other publications.

    1. 1
      Grzybowski, B. A.; Bishop, K. J. M.; Campbell, C. J.; Fialkowski, M.; Smoukov, S. K. Micro- and Nanotechnology via Reaction–diffusion. Soft Matter 2005, 1, 114– 128,  DOI: 10.1039/b501769f
      1
      Micro- and nanotechnology via reaction-diffusion
      Grzybowski, Bartosz A.; Bishop, Kyle J. M.; Campbell, Christopher J.; Fialkowski, Marcin; Smoukov, Stoyan K.
      Soft Matter (2005), 1 (2), 114-128CODEN: SMOABF; ISSN:1744-683X. (Royal Society of Chemistry)
      A review. Reaction-diffusion (RD) processes are common throughout nature, which uses them routinely to build and control structures on length scales from mol. to macroscopic. At the same time, despite a long history of scientific research and a significant level of understanding of the basic aspects of RD, reaction-diffusion has remained an unrealized technol. opportunity. This review suggests that RD systems can provide a versatile basis for applications in micro- and nanotechnol. Straightforward exptl. methods are described that allow precise control of RD processes in complex microgeometries and enable fabrication of small-scale structures, devices, and functional systems. Uses of RD in sensory applications are also discussed.
      >> More from SciFinder ®
      https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD2MXmvFCmtLo%253D&md5=ec155fb4ff1f77feaa1f43e4e47ce656
    2. 2
      Epstein, I. R.; Xu, B. Reaction–diffusion Processes at the Nano- and Microscales. Nat. Nanotechnol. 2016, 11, 312– 319,  DOI: 10.1038/nnano.2016.41
      2
      Reaction-diffusion processes at the nano- and microscales
      Epstein, Irving R.; Xu, Bing
      Nature Nanotechnology (2016), 11 (4), 312-319CODEN: NNAABX; ISSN:1748-3387. (Nature Publishing Group)
      The bottom-up fabrication of nano- and microscale structures from primary building blocks (mols., colloidal particles) has made remarkable progress over the past two decades, but most research has focused on structural aspects, leaving our understanding of the dynamic and spatiotemporal aspects at a relatively primitive stage. In this Review, we draw inspiration from living cells to argue that it is now time to move beyond the generation of structures and explore dynamic processes at the nanoscale. We first introduce nanoscale self-assembly, self-organization and reaction-diffusion processes as essential features of cells. Then, we highlight recent progress towards designing and controlling these fundamental features of life in abiol. systems. Specifically, we discuss examples of reaction-diffusion processes that lead to such outcomes as self-assembly, self-organization, unique nanostructures, chem. waves and dynamic order to illustrate their ubiquity within a unifying context of dynamic oscillations and energy dissipation. Finally, we suggest future directions for research on reaction-diffusion processes at the nano- and microscales that we find hold particular promise for a new understanding of science at the nanoscale and the development of new kinds of nanotechnologies for chem. transport, chem. communication and integration with living systems.
      >> More from SciFinder ®
      https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC28Xltlyitbc%253D&md5=7afec526a3ff15b2b3959add1326da4b
    3. 3
      Roth, W. J.; Gil, B.; Makowski, W.; Marszalek, B.; Eliášová, P. Layer Like Porous Materials with Hierarchical Structure. Chem. Soc. Rev. 2016, 45, 3400– 3438,  DOI: 10.1039/C5CS00508F
      3
      Layer like porous materials with hierarchical structure
      Roth, Wieslaw J.; Gil, Barbara; Makowski, Waclaw; Marszalek, Bartosz; Eliasova, Pavla
      Chemical Society Reviews (2016), 45 (12), 3400-3438CODEN: CSRVBR; ISSN:0306-0012. (Royal Society of Chemistry)
      Many chem. compns. produce layered solids consisting of extended sheets with thickness not greater than a few nanometers. The layers are weakly bonded together in a crystal and can be modified into various nanoarchitectures including porous hierarchical structures. Several classes of 2-dimensional (2D) materials have been extensively studied and developed because of their potential usefulness as catalysts and sorbents. They are discussed in this review with focus on clays, layered transition metal oxides, silicates, layered double hydroxides, metal(IV) phosphates and phosphonates, esp. zirconium, and zeolites. Pillaring and delamination are the primary methods for structural modification and pore tailoring. The reported approaches are described and compared for the different classes of materials. The methods of characterization include identification by X-ray diffraction and microscopy, pore size anal. and activity assessment by IR spectroscopy and catalytic testing. The discovery of layered zeolites was a fundamental breakthrough that created unprecedented opportunities because of (i) inherent strong acid sites that make them very active catalytically, (ii) porosity through the layers and (iii) bridging of 2D and 3D structures. Approx. 16 different types of layered zeolite structures and modifications have been identified as distinct forms. It is also expected that many among the over 200 recognized zeolite frameworks can produce layered precursors. Addnl. advances enabled by 2D zeolites include synthesis of layered materials by design, hierarchical structures obtained by direct synthesis and top-down prepn. of layered materials from 3D frameworks.
      >> More from SciFinder ®
      https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2MXhs12ksLrN&md5=304044f5744f0a311d4fab337f0a3033
    4. 4
      Shehzad, K.; Xu, Y.; Gao, C.; Duan, X. Three-dimensional Macro-structures of Two-dimensional Nanomaterials. Chem. Soc. Rev. 2016, 45, 5541– 5588,  DOI: 10.1039/C6CS00218H
      4
      Three-dimensional macro-structures of two-dimensional nanomaterials
      Shehzad, Khurram; Xu, Yang; Gao, Chao; Duan, Xiangfeng
      Chemical Society Reviews (2016), 45 (20), 5541-5588CODEN: CSRVBR; ISSN:0306-0012. (Royal Society of Chemistry)
      If two-dimensional (2D) nanomaterials are ever to be utilized as components of practical, macroscopic devices on a large scale, there is a complementary need to controllably assemble these 2D building blocks into more sophisticated and hierarchical three-dimensional (3D) architectures. Such a capability is key to design and build complex, functional devices with tailored properties. This review provides a comprehensive overview of the various exptl. strategies currently used to fabricate the 3D macro-structures of 2D nanomaterials. Addnl., various approaches for the decoration of the 3D macro-structures with org. mols., polymers, and inorg. materials are reviewed. Finally, we discuss the applications of 3D macro-structures, esp. in the areas of energy, environment, sensing, and electronics, and describe the existing challenges and the outlook for this fast emerging field.
      >> More from SciFinder ®
      https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC28Xht1ers7jN&md5=7bb7599d233149bc1f2ed7e8d28bc662
    5. 5
      Yang, X.-Y.; Chen, L.-H.; Li, Y.; Rooke, J. C.; Sanchez, C.; Su, B.-L. Hierarchically Porous Materials: Synthesis Strategies and Structure Design. Chem. Soc. Rev. 2017, 46, 481– 558,  DOI: 10.1039/C6CS00829A
      5
      Hierarchically porous materials: synthesis strategies and structure design
      Yang, Xiao-Yu; Chen, Li-Hua; Li, Yu; Rooke, Joanna Claire; Sanchez, Clement; Su, Bao-Lian
      Chemical Society Reviews (2017), 46 (2), 481-558CODEN: CSRVBR; ISSN:0306-0012. (Royal Society of Chemistry)
      Owing to their immense potential in energy conversion and storage, catalysis, photocatalysis, adsorption, sepn. and life science applications, significant interest has been devoted to the design and synthesis of hierarchically porous materials. The hierarchy of materials on porosity, structural, morphol., and component levels is key for high performance in all kinds of applications. Synthesis and applications of hierarchically structured porous materials have become a rapidly evolving field of current interest. A large series of synthesis methods have been developed. This review addresses recent advances made in studies of this topic. After identifying the advantages and problems of natural hierarchically porous materials, synthetic hierarchically porous materials are presented. The synthesis strategies used to prep. hierarchically porous materials are first introduced and the features of synthesis and the resulting structures are presented using a series of examples. These involve templating methods (surfactant templating, nanocasting, macroporous polymer templating, colloidal crystal templating and bioinspired process, i.e. biotemplating), conventional techniques (supercrit. fluids, emulsion, freeze-drying, breath figures, selective leaching, phase sepn., zeolitization process, and replication) and basic methods (sol-gel controlling and post-treatment), as well as self-formation phenomenon of porous hierarchy. A series of detailed examples are given to show methods for the synthesis of hierarchically porous structures with various chem. compns. (dual porosities: micro-micropores, micro-mesopores, micro-macropores, meso-mesopores, meso-macropores, multiple porosities: micro-meso-macropores and meso-meso-macropores). We hope that this review will be helpful for those entering the field and also for those in the field who want quick access to helpful ref. information about the synthesis of new hierarchically porous materials and methods to control their structure and morphol.
      >> More from SciFinder ®
      https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC28XhvFOitrfM&md5=d496ddd01cb671880e1b4912f2036bf4
    6. 6
      Liesegang, R. E. Ueber einige Eigenschaften von Gallerten. Naturwiss. Wochenschr. 1896, 11, 353– 362
      There is no corresponding record for this reference.
    7. 7
      Nabika, H.; Itatani, M.; Lagzi, I. Pattern Formation in Precipitation Reactions: The Liesegang Phenomenon. Langmuir 2020, 36, 481– 497,  DOI: 10.1021/acs.langmuir.9b03018
      7
      Pattern Formation in Precipitation Reactions: The Liesegang Phenomenon
      Nabika, Hideki; Itatani, Masaki; Lagzi, Istvan
      Langmuir (2020), 36 (2), 481-497CODEN: LANGD5; ISSN:0743-7463. (American Chemical Society)
      A review. Pattern formation is a frequent phenomenon in physics, chem., biol. and material science. Bottom-up pattern formation occurs usually in the interaction of the transport phenomena of chem. species with their chem. reaction. The oldest pattern formation is the Liesegang phenomenon (or periodic pptn.), which was discovered and described by Raphael Edward Liesegang in 1896, who was a German chemist and photographer, and he was born 150 years ago. The purpose of this review is to provide a comprehensive overview of this type of pattern formation. Liesegang banding occurs due to the coupling of the diffusion process of the reagents to their chem. reactions in solid hydrogels. We will discuss several phenomena obsd. and discovered in the past century including reverse patterns, pptn. patterns with dissoln. (due to complex formation), helicoidal patterns, and pptn. waves. Addnl., we will review all existing models of the Liesegang phenomenon including pre- and post-nucleation scenarios. Finally, we will highlight several applications of periodic pptn.
      >> More from SciFinder ®
      https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC1MXit1CrsrrN&md5=28efdfec8ee95573c635fcde08b0c8b4
    8. 8
      Nakouzi, E.; Steinbock, O. Self-organization in Precipitation Reactions Far from the Equilibrium. Sci. Adv. 2016, 2, e1601144  DOI: 10.1126/sciadv.1601144
      8
      Self-organization in precipitation reactions far from the equilibrium
      Nakouzi, Elias; Steinbock, Oliver
      Science Advances (2016), 2 (8), e1601144/1-e1601144/13CODEN: SACDAF; ISSN:2375-2548. (American Association for the Advancement of Science)
      Far from the thermodn. equil., many pptn. reactions create complex product structures with fascinating features caused by their unusual origins. Unlike the dissipative patterns in other self-organizing reactions, these features can be permanent, suggesting potential applications in materials science and engineering. We review four distinct classes of pptn. reactions, describe similarities and differences, and discuss related challenges for theor. studies. These classes are hollow micro- and macrotubes in chem. gardens, polycryst. silica carbonate aggregates (biomorphs), Liesegang bands, and propagating pptn.-dissoln. fronts. In many cases, these systems show intricate structural hierarchies that span from the nanometer scale into the macroscopic world. We summarize recent exptl. progress that often involves growth under tightly regulated conditions by means of wet stamping, holog. heating, and controlled elec., magnetic, or pH perturbations. In this research field, progress requires mechanistic insights that cannot be derived from expts. alone. We discuss how mesoscopic aspects of the product structures can be modeled by reaction-transport equations and suggest important targets for future studies that should also include materials features at the nanoscale.
      >> More from SciFinder ®
      https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC1cXkslKqt7w%253D&md5=fca00dd5dd11e40c756bdb23f727b1b4
    9. 9
      Lagzi, I. Controlling and Engineering Precipitation Patterns. Langmuir 2012, 28, 3350– 3354,  DOI: 10.1021/la2049025
      9
      Controlling and Engineering Precipitation Patterns
      Lagzi, Istvan
      Langmuir (2012), 28 (7), 3350-3354CODEN: LANGD5; ISSN:0743-7463. (American Chemical Society)
      Controlling and engineering chem. structures are the most important scientific challenges in material science. Pptn. patterns from ions or nanoparticles are promising candidates for designing bulk structure for catalysis, energy prodn., storage, and electronics. There are only a few procedures and techniques to control pptn. (Liesegang) patterns in gel media (e.g., using an elec. field, varying the initial concn. of the electrolytes). However, those methods provide just a limited degree of freedom. Here, the authors provide a robust and transparent way to control and engineer Liesegang patterns by varying gel concn. and inducing impurity by addn. of gelatin to agarose gel. Using this exptl. method, different pptn. structures can be obtained with different width and spatial distribution of the formed bands. A new variant of a sol-coagulation model was developed to describe and understand the effect of the gel concn. and impurities on Liesegang pattern formation.
      >> More from SciFinder ®
      https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC38XhsVWjurc%253D&md5=1d4fcca37f4d5f4c3d2b3042f39356ec
    10. 10
      Smoukov, S. K.; Bitner, A.; Campbell, C. J.; Kandere-Grzybowska, K.; Grzybowski, B. A. Nano- and Microscopic Surface Wrinkles of Linearly Increasing Heights Prepared by Periodic Precipitation. J. Am. Chem. Soc. 2005, 127, 17803– 17807,  DOI: 10.1021/ja054882j
      10
      Nano- and Microscopic Surface Wrinkles of Linearly Increasing Heights Prepared by Periodic Precipitation
      Smoukov, Stoyan K.; Bitner, Agnieszka; Campbell, Christopher J.; Kandere-Grzybowska, Kristiana; Grzybowski, Bartosz A.
      Journal of the American Chemical Society (2005), 127 (50), 17803-17807CODEN: JACSAT; ISSN:0002-7863. (American Chemical Society)
      Arrays of surface wrinkles of linearly increasing heights (from tens of nanometers to tens of micrometers) were prepd. via a spontaneous reaction-diffusion process based on periodic pptn. The slopes, dimensions, and positions of the pptn. bands could be controlled precisely by adjusting the concns. of the participating chems. as well as the material properties of patterned substrates. Addnl. control of periodic pptn. by localized UV irradn. allowed for the prepn. of discontinuous and curvilinear structures. The nonbinary 3-dimensional surface topogs. were replicated into poly(dimethylsiloxane), and the applications of replicas in microfluidics, microsepns., and cell biol. were suggested.
      >> More from SciFinder ®
      https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD2MXht1CkurzK&md5=a6816a6e8b0bb1789d8cd49f3edd9788
    11. 11
      Badr, L.; Sultan, R. Ring Morphology and pH Effects in 2D and 1D Co(OH)2 Liesegang Systems. J. Phys. Chem. A 2009, 113, 6581– 6586,  DOI: 10.1021/jp8094984
      11
      Ring Morphology and pH Effects in 2D and 1D Co(OH)2 Liesegang Systems
      Badr, Layla; Sultan, Rabih
      Journal of Physical Chemistry A (2009), 113 (24), 6581-6586CODEN: JPCAFH; ISSN:1089-5639. (American Chemical Society)
      The authors study the factors that affect the morphol. of Co(OH)2 Liesegang rings, in a way to obtain concentric rings with large spacing, upon an appropriate variation in the exptl. conditions. Such well-resolved patterns are obtained under optimum conditions: decrease in the concn. of the outer electrolyte, increase in the concn. of both the inner electrolyte and the gelatin in the hosting gel medium, and increase in the strength of a const. radial elec. field applied across the pattern domain. The effect of pH on the bands in a 1-dimensional Co(OH)2 Liesegang pattern is also studied. The initial pH of the diffusing soln. plays a central role in altering the band morphol., because the outer electrolyte (NH4OH) is a base, strongly affected by the H+ equil. The no. of bands decreases and the interband spacing increases with decreasing pH of the NH4OH soln. The pattern morphol. in that case is controlled by the NH4Cl/NH4OH ratio.
      >> More from SciFinder ®
      https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD1MXmtF2ks7g%253D&md5=af71ce06cf80b8f1c88666754ef91cbb
    12. 12
      Antal, T.; Droz, M.; Magnin, J.; Rácz, Z.; Zrinyi, M. Derivation of the Matalon-Packter Law for Liesegang patterns. Chem. Phys. 1998, 109, 9479– 9486,  DOI: 10.1063/1.477609
      12
      Derivation of the Matalon-Packter law for Liesegang patterns
      Antal, T.; Droz, M.; Magnin, J.; Racz, Z.; Zrinyi, M.
      Journal of Chemical Physics (1998), 109 (21), 9479-9486CODEN: JCPSA6; ISSN:0021-9606. (American Institute of Physics)
      Theor. models of the Liesegang phenomena are studied and simple expressions for the spacing coeffs. characterizing the patterns are derived. The emphasis is on displaying the explicit dependences on the concns. of the inner and the outer electrolytes. Competing theories (ion-product supersatn., nucleation and droplet growth, induced sol-coagulation) are treated with the aim of finding the distinguishing features of the theories. The predictions are compared with expts. and the results suggest that the induced sol-coagulation theory is the best candidate for describing the exptl. observations embodied in the Matalon-Packter law.
      >> More from SciFinder ®
      https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaK1cXntlWgtLk%253D&md5=4ab5e2e2e30b94687d783fc024227bdc
    13. 13
      Thomas, S.; Molnár, F.; Rácz, Z.; Lagzi, I. Matalon–Packter Law for Stretched Helicoids Formed in Precipitation Processes. Chem. Phys. Lett. 2013, 577, 38– 41,  DOI: 10.1016/j.cplett.2013.05.031
      13
      Matalon-Packter law for stretched helicoids formed in precipitation processes
      Thomas, Shibi; Molnar, Ferenc; Racz, Zoltan; Lagzi, Istvan
      Chemical Physics Letters (2013), 577 (), 38-41CODEN: CHPLBC; ISSN:0009-2614. (Elsevier B.V.)
      Helicoid-like pptn. structures emerging in the wake of reaction-diffusion fronts are studied exptl. as well as theor. We find that the helicoids are stretched, their local pitch behind the advancing front increases exponentially. We compare this result to the exponential increase of the band spacing in Liesegang phenomena. The spacing coeff. (p) characterizing the exponential increase satisfies the same Matalon-Packter law in both cases, i.e. p ∼ 1/a0 where a0 is the initial concn. of the outer electrolyte in the exptl. setup. Our expts. also reveal that, at the microstructure level, the helicoids are assembled from building blocks of micron-size achiral spherulites.
      >> More from SciFinder ®
      https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3sXptFWgtr0%253D&md5=c724a4cf987d5aa8530a22aead923f66
    14. 14
      Itatani, M.; Fang, Q.; Nabika, H. Modification of the Matalon–Packter Law for Self-Organized Periodic Precipitation Patterns by Incorporating Time-Dependent Diffusion Flux. J. Phys. Chem. B 2021, 125, 6921– 6929,  DOI: 10.1021/acs.jpcb.1c02175
      14
      Modification of the Matalon-Packter Law for Self-Organized Periodic Precipitation Patterns by Incorporating Time-Dependent Diffusion Flux
      Itatani, Masaki; Fang, Qing; Nabika, Hideki
      Journal of Physical Chemistry B (2021), 125 (25), 6921-6929CODEN: JPCBFK; ISSN:1520-5207. (American Chemical Society)
      Spontaneous pattern formation is common in both inanimate and living systems. Although the Liesegang pattern (LP) is a well-studied chem. model for pptn. patterns, various recent LP systems based on artificial control could not be easily evaluated using classical tools. The Matalon-Packter (MP) law describes the effect of the initial electrolyte concn., which governs the diffusion flux (Fdiff), on the spatial distribution of LP. Note that the classical MP law only considers Fdiff through the initial concn. of electrolytes, even though it should also depend on the vol. of the reservoir used for the outer electrolyte because of the temporal change in the concn. therein due to diffusion. However, there has been no report on the relationship between the MP law, the reservoir vol., and Fdiff. Here, we exptl. demonstrated and evaluated the effect of the reservoir vol. on LP periodicity according to the classical MP law. Numerical simulations revealed that the reservoir vol. affects the temporal modulation of Fdiff. By expressing the MP law as a function of estd. Fdiff after a certain period of time, we provide a uniform description of the changes in periodicity for both small and large reservoir vols. Such modification should make the MP law a more robust tool for studying LP systems.
      >> More from SciFinder ®
      https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BB3MXhtlWltbjE&md5=57c596530b2cf6b8da8dd55a396bad99
    15. 15
      Itatani, M.; Fang, Q.; Unoura, K.; Nabika, H. Programmable Design of Self-Organized Patterns through a Precipitation Reaction. J. Phys. Chem. B 2020, 124, 8402– 8409,  DOI: 10.1021/acs.jpcb.0c05603
      15
      Programmable Design of Self-Organized Patterns through a Precipitation Reaction
      Itatani, Masaki; Fang, Qing; Unoura, Kei; Nabika, Hideki
      Journal of Physical Chemistry B (2020), 124 (38), 8402-8409CODEN: JPCBFK; ISSN:1520-5207. (American Chemical Society)
      Nature uses self-organized spatiotemporal patterns to construct systems with robustness and flexibility. Furthermore, understanding the principles underlying self-organization in nature enables programmable design of artificial patterns driven by chem. energy. The related mechanisms are however not clearly understood because most of these patterns are formed in reaction-diffusion (RD) systems consisting of intricate interaction between diffusion and reaction. Therefore, comprehensive understanding of the pattern formation may provide crit. knowledge for developing novel strategies in both natural science and chem. engineering. Liesegang patterns (LPs) are one of the typical programmable patterns. This study demonstrates that appropriate tuning of gel concn. distribution is a key programming factor for controlling LP periodicities. The gel distribution was realized in bi- or multilayered gels constructed by stacking agarose gels of different concns. Thus, exceptional LP periodicities were achieved locally in bilayered gels. Furthermore, RD simulations revealed that the nucleation process modulated by the gel distribution dets. the LP periodicity in bilayered gels. Finally, based on this concept, desired LP periodicities were successfully realized by programming gel distributions in multilayered gels. Thus, deep insights into the fundamental role of nucleation in designing LPs can lead to the practical applications of LPs and the understanding of self-organization in nature.
      >> More from SciFinder ®
      https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BB3cXitFCls7rN&md5=fd932f5bd48607e6f6517a4482619524
    16. 16
      Morsali, M.; Khan, M. T. A.; Ashirov, R.; Hollo, G.; Baytekin, H. T.; Lagzi, I.; Baytekin, B. Mechanical Control of Periodic Precipitation in Stretchable Gels to Retrieve Information on Elastic Deformation and for the Complex Patterning of Matter. Adv. Mater. 2020, 32, 1905779  DOI: 10.1002/adma.201905779
      16
      Mechanical Control of Periodic Precipitation in Stretchable Gels to Retrieve Information on Elastic Deformation and for the Complex Patterning of Matter
      Morsali, Mohammad; Khan, Muhammad Turab Ali; Ashirov, Rahym; Hollo, Gabor; Baytekin, H. Tarik; Lagzi, Istvan; Baytekin, Bilge
      Advanced Materials (Weinheim, Germany) (2020), 32 (10), 1905779CODEN: ADVMEW; ISSN:0935-9648. (Wiley-VCH Verlag GmbH & Co. KGaA)
      Material design using nonequil. systems provides straightforward access to complexity levels that are possible through dynamic processes. Pattern formation through nonequil. processes and reaction-diffusion can be used to achieve this goal. Liesegang patterns (LPs) are a kind of periodic pptn. patterns formed through reaction-diffusion. So far, it has been shown that the periodic band structure of LPs and the geometry of the pattern can be controlled by exptl. conditions and external fields (e.g., elec. or magnetic). However, there are no examples of these systems being used to retrieve information about the changes in the environment as they form, and there are no studies making use of these patterns for complex material prepn. This work shows the formation of LPs by a diffusion-pptn. reaction in a stretchable hydrogel and the control of the obtained patterns by the unprecedented and uncommon method of mech. input. Addnl., how to use this protocol and how deviations from "LP behavior" of the patterns can be used to "write and store" information about the time, duration, extent, and direction of gel deformation are presented. Finally, an example of using complex patterning to deposit polypyrrole by using pptn. patterns is shown as a template.
      >> More from SciFinder ®
      https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BB3cXjt1Omug%253D%253D&md5=e4376d316c43544cd7f735efe3445c80
    17. 17
      Zakhia Douaihy, R.; Al-Ghoul, M.; Hmadeh, M. Liesegang Banding for Controlled Size and Growth of Zeolitic-Imidazolate Frameworks. Small 2019, 15, 1901605  DOI: 10.1002/smll.201901605
      There is no corresponding record for this reference.
    18. 18
      Sultan, R.; Halabieh, R. Effect of an Electric Field on Propagating Co(OH)2 Liesegang Patterns. Chem. Phys. Lett. 2000, 332, 331– 338,  DOI: 10.1016/S0009-2614(00)01200-8
      18
      Effect of an electric field on propagating Co(OH)2 Liesegang patterns
      Sultan, R.; Halabieh, R.
      Chemical Physics Letters (2000), 332 (3,4), 331-338CODEN: CHPLBC; ISSN:0009-2614. (Elsevier Science B.V.)
      The effect of an applied DC elec. field on the propagation of a Co(OH)2 Liesegang pattern from Co2+ and NH4OH is investigated. The field free pattern is known to propagate down the tube due to band dissoln. at the top and band formation at the bottom. At a fixed concn. of Co2+ (0.134 M), the front propagation is accelerated by the field which is applied in the direction of wave propagation. The pattern propagates faster under a higher voltage. The dependence of wave velocity on field strength is non-linear. When the concn. of Co2+ is varied at const. voltage (6.00 V), two opposite trends are obtained. Below a characteristic time tc=1.7 days, the velocity of propagation increases with decreasing concn. and above tc, the velocity increases with increasing concn. This latter behavior (above tc) completely reverses the field free trend. The effect of the field on the morphol. appearance of the bands is discussed.
      >> More from SciFinder ®
      https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD3cXovFemtb4%253D&md5=0ae9a62fac6cd55eb32de9b76eafaa02
    19. 19
      Badr, L.; Moussa, Z.; Hariri, A.; Sultan, R. Band, Target, and Onion Patterns in Co(OH)2 Liesegang Systems. Phys. Rev. E 2011, 83, 016109  DOI: 10.1103/PhysRevE.83.016109
      19
      Band, target, and onion patterns in Co(OH)2 Liesegang systems
      Badr, Layla; Moussa, Zeinab; Hariri, Amani; Sultan, Rabih
      Physical Review E: Statistical, Nonlinear, and Soft Matter Physics (2011), 83 (1-2), 016109/1-016109/6CODEN: PRESCM; ISSN:1539-3755. (American Physical Society)
      Liesegang expts. producing Co(OH)2 stratification were done, in one, two, and three dimensions for comparison of the pattern morphologies. The authors obtain well-resolved bands in one dimension, target patterns (rings) in two dimensions, and onion patterns (spherical shells) in three dimensions. The morphol. characteristics of the various patterns (spacing coeffs., rate of growth of ring spacing with distance) were measured. The spacing ratio of the strata in the different spatial dimensions was found to be anticorrelated with the surface-to-vol. ratio of the gel domain. Some studies featuring the importance of morphol. in Liesegang systems are briefly surveyed.
      >> More from SciFinder ®
      https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3MXhsFSgtrs%253D&md5=c0b473660629d793faa5ca0e06884c22
    20. 20
      Park, J. H.; Paczesny, J.; Kim, N.; Grzybowski, B. A. Shaping Microcrystals of Metal-Organic Frameworks by Reaction-Diffusion. Angew. Chem., Int. Ed. 2020, 59, 10301– 10305,  DOI: 10.1002/anie.201910989
      20
      Shaping Microcrystals of Metal-Organic Frameworks by Reaction-Diffusion
      Park, Jun Heuk; Paczesny, Jan; Kim, Namhun; Grzybowski, Bartosz A.
      Angewandte Chemie, International Edition (2020), 59 (26), 10301-10305CODEN: ACIEF5; ISSN:1433-7851. (Wiley-VCH Verlag GmbH & Co. KGaA)
      When components of a metal-org. framework (MOF) and a crystal growth modulator diffuse through a gel medium, they can form arrays of regularly-spaced pptn. bands contg. MOF crystals of different morphologies. With time, slow variations in the local concns. of the growth modulator cause the crystals to change their shapes, ultimately resulting in unusual concave microcrystallites not available via soln.-based methods. The reaction-diffusion and periodic pptn. phenomena (1) extend to various types of MOFs and also MOPs (metal-org. polyhedra), and (2) can be multiplexed to realize within one gel multiple growth conditions, in effect leading to various cryst. phases or polycryst. formations.
      >> More from SciFinder ®
      https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BB3cXntFGitLc%253D&md5=789a6419744fe3e6fb3310c65aa96d50
    21. 21
      Karam, T.; El-Rassy, H.; Sultan, R. Mechanism of Revert Spacing in a PbCrO4 Liesegang System. J. Phys. Chem. A 2011, 115, 2994– 2998,  DOI: 10.1021/jp200619g
      21
      Mechanism of Revert Spacing in a PbCrO4 Liesegang System
      Karam, Tony; El-Rassy, Houssam; Sultan, Rabih
      Journal of Physical Chemistry A (2011), 115 (14), 2994-2998CODEN: JPCAFH; ISSN:1089-5639. (American Chemical Society)
      Periodic pptn. of sparingly sol. salts yields parallel Liesegang bands in 1-dimensional whose spacings obey either one of two known trends. The overwhelming trend is an increase in spacing as the authors move away from the junction, while some systems display a decrease in spacing as the bands get further away from the interface. The latter trend is much less common and is known as the revert spacing law. Whereas the direct (normal) spacing law is generally well-undertsood, the revert spacing trend was not explicitly and distinctly elucidated. The authors propose a mechanism of revert spacing governed by the adsorption of the diffusing CrO42- ions on the formed PbCrO4 Liesegang bands and carry out a set of expts. that support the suggested scenario. This adsorption increases as the band no. (n) increases in revert spacing systems, while it decreases as n increases in direct spacing systems. This correlation in opposite directions decisively reveals the role of adsorption in the mechanism. The attraction between the CrO42- and Pb2+ in the gel causes the bands to form gradually closer and closer. Secondary structure (thinner bands formed within the main ones) obtained under some conditions is discussed in view of the light sensitivity of the chromate ion and the stability of the lead chromate sol.
      >> More from SciFinder ®
      https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3MXjvVaqu78%253D&md5=8b2e9dcf354bde3dd9e9b9e09f8d5e49
    22. 22
      Kalash, L.; Farah, H.; Eddin, A. Z.; Sultan, R. Dynamical Profiles of the Reactive Components in Direct and Revert Liesegang Patterns. Chem. Phys. Lett. 2013, 590, 69– 73,  DOI: 10.1016/j.cplett.2013.10.035
      22
      Dynamical profiles of the reactive components in direct and revert Liesegang patterns
      Kalash, Leen; Farah, Hiba; Eddin, Amal Zein; Sultan, Rabih
      Chemical Physics Letters (2013), 590 (), 69-73CODEN: CHPLBC; ISSN:0009-2614. (Elsevier B.V.)
      In periodic pptn. (Liesegang banding), the overwhelmingly common trend is the increase in spacing between consecutive bands as we move away from the interface. Revert spacing is a rare trend obsd. in a few systems, wherein the spacing decreases with distance from the interface. In this Letter, we compare the spatial profiles of the aq. components in two chromate Liesegang ppts.: CuCrO4 and PbCrO4, displaying direct and revert spacing, resp. The profiles are measured using UV-Vis spectrophotometry. The formation of a Pb2+-PbCrO4 complex in equil. with the free Pb2+, seems to play a key role in the revert spacing scenario.
      >> More from SciFinder ®
      https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3sXhslaitb%252FI&md5=6a735b17930ddbfda99a03a669704bd1
    23. 23
      Ezzeddine, D.; El-Rassy, H.; Sultan, R. Surface and Structural Studies in a PbCrO4 Liesegang Pattern with Revert Spacing. Chem. Phys. Lett. 2019, 734, 136735  DOI: 10.1016/j.cplett.2019.136735
      23
      Surface and structural studies in a PbCrO4 Liesegang pattern with revert spacing
      Ezzeddine, Dalia; El-Rassy, Houssam; Sultan, Rabih
      Chemical Physics Letters (2019), 734 (), 136735CODEN: CHPLBC; ISSN:0009-2614. (Elsevier B.V.)
      We present a novel study of a PbCrO4 Liesegang pattern exhibiting revert spacing. SEM, Atomic Absorption Spectrometry (AAS) and Energy Dispersive X-ray (EDX) spectroscopy measurements are carried out, and are shown to support the adsorption of CrO2-4 on the ppt., which becomes more enhanced as we move farther from the gel interface. Such an ascending differential adsorption scenario favors revert spacing over the direct spacing trend.
      >> More from SciFinder ®
      https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC1MXhslGmsLvL&md5=2ea53e3dbd933bac9380f0ed907d8caa
    24. 24
      Kanniah, N.; Gnanam, F. D.; Ramasamy, P.; Laddha, G. S. Revert and Direct Type Liesegang Phenomenon of Silver Iodide. J. Colloid Interface Sci. 1981, 80, 369– 376,  DOI: 10.1016/0021-9797(81)90195-8
      24
      Revert and direct type Liesegang phenomenon of silver iodide
      Kanniah, N.; Gnanam, F. D.; Ramasamy, P.; Laddha, G. S.
      Journal of Colloid and Interface Science (1981), 80 (2), 369-76CODEN: JCISA5; ISSN:0021-9797.
      The exptl. conditions for Liesegang phenomenon of AgI in agar gel columns, and particularly the transition from revert to direct type of periodic pptns., were studied. The theor. derived Mathur's spacing law, which suits both revert and direct type of Liesegang's rings, was verified exptl. An attempt is made to explain the mechanism of revert and direct type and of the transition of revert to direct type of periodic pptn. on the basis of adsorption on the pptd. AgI and of flocculation. The dependence of the transition point on the concns. of the outer and inner electrolytes was studied. The time law of Morse and Pierce is verified. The dependence of the rate const. (K = xn/tn1/2) on the concn. of the outer and inner electrolytes was studied.
      >> More from SciFinder ®
      https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaL3MXhs1eiur8%253D&md5=14f1063ab0db6eb96e55da52413a7636
    25. 25
      Kanniah, N.; Gnanam, F. D.; Ramasamy, P. Revert and Direct Liesegang Phenomenon of Silver Iodide: Factors Influencing the Transition Point. J. Colloid Interface Sci. 1983, 94, 412– 420,  DOI: 10.1016/0021-9797(83)90281-3
      25
      Revert and direct Liesegang phenomenon of silver iodide: factors influencing the transition point
      Kanniah, N.; Gnanam, F. D.; Ramasamy, P.
      Journal of Colloid and Interface Science (1983), 94 (2), 412-20CODEN: JCISA5; ISSN:0021-9797.
      A new theory based on the DLVO theory of stability of colloids was proposed to explain the mechanism of revert and direct Liesegang phenomenon and the transition of revert to direct type. This theory takes into account the surface potential, the zeta potential, the zero point of charge and the reversal of charge of the sol particles. The factors influencing the transition point are reported. The concn. and pH of the gel have a pronounced effect on the transition of revert to direct. The influence of different additives is discussed.
      >> More from SciFinder ®
      https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaL3sXksF2nsbw%253D&md5=bb225a7be385811718a5b33de426df51
    26. 26
      Kanniah, N.; Gnanam, F. D.; Ramasamy, P. A New Spacing Law for Liesegang Rings. Proc. - Indian Acad. Sci. 1984, 93, 801– 811,  DOI: 10.1007/BF02866341
      26
      A new spacing law for Liesegang rings
      Kanniah, N.; Gnanam, F. D.; Ramasamy, P.
      Proceedings - Indian Academy of Sciences, Chemical Sciences (1984), 93 (5), 801-11CODEN: PIAADM; ISSN:0253-4134.
      The spacing laws of Jablczynski (1923) and Mathut (1961) were applied to the Liesegang rings of Co(II) oxinate, AgI, and PbCrO4 in agar gel. Although Jablcynski's spacing law satisfactorily explains the direct Liesegang rings, it totally fails to describe the revert Liesegang rings. Similarly though Mathur's spacing law is applicable to both revert and direct type of periodic pptn., an appreciable deviation is obsd. in systems with greater interspacing. A new spacing law, applicable to both revert and direct Liesegang rings, is proposed on the basis of the preferential adsorption theory of Liesegang rings. It is verified exptl. with AgI and PbCrO4 systems.
      >> More from SciFinder ®
      https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaL2cXltFOns7w%253D&md5=d9b0b40f44089e41af094858b4a0f1b5
    27. 27
      Kulkarni, S. D.; Walimbe, P. C.; Ingulkar, R. B.; Lahase, J. D.; Kulkarni, P. S. Revert Banding in One-Dimensional Periodic Precipitation of the (AgNO3 + KBr) System in Agar Gel. ACS Omega 2019, 4, 13061– 13068,  DOI: 10.1021/acsomega.9b00937
      27
      Revert banding in one-dimensional periodic precipitation of (AgNO3 + KBr) system in agar gel
      Kulkarni, Sunil D.; Walimbe, Prasad C.; Ingulkar, Rohit B.; Lahase, Jagdish D.; Kulkarni, Preeti S.
      ACS Omega (2019), 4 (8), 13061-13068CODEN: ACSODF; ISSN:2470-1343. (American Chemical Society)
      A periodically pptg. system wherein interband distance successively decreases is known as revert Liesegang banding. The phenomenon is rare, and the underlying mechanism is implicit. In the present paper, the Liesegang system comprising of AgNO3 and KBr as the outer and inner electrolyte pair showing revert banding in agar gel by employing a 1D exptl. setup is studied under varying concns. of participating species. Revert banding was obsd. under all the exptl. conditions. The concns. of inner and outer electrolytes were found to play a major role in reverting since they build the ionic strength inside Liesegang tubes. We hypothesize that the band reverting is the interplay of van der Waals and elec. double-layer interactions, and hence classical DLVO (Derjaguin-Landau-Verwey-Overbeek) theory can be applied to interpret reverting. We propose that revert deposition of ppts. is the outcome of flocculation and peptization of sols, which is the manifestation of balancing attractive and repulsive interactions acting on colloidal particles responsible for band formation.
      >> More from SciFinder ®
      https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC1MXhsFWkt7zJ&md5=7f447015612bd2ef18ec7b37dd3da6f4
    28. 28
      Smoukov, S. K.; Lagzi, I.; Grzybowski, B. A. Independence of Primary and Secondary Structures in Periodic Precipitation Patterns. J. Phys. Chem. Lett. 2011, 2, 345– 349,  DOI: 10.1021/jz101679t
      28
      Independence of Primary and Secondary Structures in Periodic Precipitation Patterns
      Smoukov, Stoyan K.; Lagzi, Istvan; Grzybowski, Bartosz A.
      Journal of Physical Chemistry Letters (2011), 2 (4), 345-349CODEN: JPCLCD; ISSN:1948-7185. (American Chemical Society)
      Microscopic periodic pptn. patterns featuring both primary and secondary bands form in thin gel films. The initial conditions for the pptn. process are defined by wet stamping and are chosen such that the primary and secondary structures are not necessarily collinear; the fact that these structures propagate in different directions suggests that they form independently of one another. This hypothesis is further supported by a theor. model in which two different intermediate species mediate band formation.
      >> More from SciFinder ®
      https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3MXhtlCksr8%253D&md5=05fef5d70103b4a3500ad8f6df40f75b
    29. 29
      Tóth, R.; Walliser, R. M.; Lagzi, I.; Boudoire, F.; Duggelin, M.; Braun, A.; Housecroft, C. E.; Constable, E. C. Probing the Mystery of Liesegang Band Formation: Revealing the Origin of Self-organized Dual-frequency Micro and Nanoparticle Arrays. Soft Matter 2016, 12, 8367– 8374,  DOI: 10.1039/C6SM01564F
      29
      Probing the mystery of Liesegang band formation: revealing the origin of self-organized dual-frequency micro and nanoparticle arrays
      Toth, Rita; Walliser, Roche M.; Lagzi, Istvan; Boudoire, Florent; Duggelin, Marcel; Braun, Artur; Housecroft, Catherine E.; Constable, Edwin C.
      Soft Matter (2016), 12 (40), 8367-8374CODEN: SMOABF; ISSN:1744-683X. (Royal Society of Chemistry)
      Periodic pptn. processes in gels can result in impressive micro- and nanostructured patterns known as periodic pptn. (or Liesegang bands). Under certain conditions, the silver nitrate-chromium(VI) system exhibits the coexistence of two kinds of Liesegang bands with different frequencies. We now present that the two kinds of bands form independently on different time scales and the pH-dependent chromate(VI)-dichromate(VI) equil. controls the formation of the ppts. We detd. the spatial distribution and constitution of the particles in the bands using focused ion beam-SEM (FIB-SEM) and scanning transmission X-ray spectromicroscopy (STXM) measurements. This provided the necessary empirical input data to formulate a model for the pattern formation; a model that quant. reproduces the exptl. observations. Understanding the pattern-forming process at the mol. level enables us to tailor the size and the shape of the bands, which, in turn, can lead to new functional architectures for a range of applications.
      >> More from SciFinder ®
      https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC28XhsVKjurbI&md5=894ddf97187492262d714cafb3ffa76e
    30. 30
      Khan, M. T. A.; Kwiczak-Yiğitbaşı, J.; Tootoonchian, P.; Morsali, M.; Lagzi, I.; Baytekin, B. Chemical Tracking of Temperature by Concurrent Periodic Precipitation Pattern Formation in Polyacrylamide Gels. ACS Appl. Mater. Interfaces 2022, 14, 7252– 7260,  DOI: 10.1021/acsami.1c20640
      30
      Chemical Tracking of Temperature by Concurrent Periodic Precipitation Pattern Formation in Polyacrylamide Gels
      Khan, Muhammad Turab Ali; Kwiczak-Yigitbasi, Joanna; Tootoonchian, Pedram; Morsali, Mohammad; Lagzi, Istvan; Baytekin, Bilge
      ACS Applied Materials & Interfaces (2022), 14 (5), 7252-7260CODEN: AAMICK; ISSN:1944-8244. (American Chemical Society)
      In nature, nonequil. systems reflect environmental changes, and these changes are often "recorded" in their solid body as they develop. Periodic pptn. patterns, aka Liesegang patterns (LPs), are visual sums of complex events in nonequil. reaction-diffusion processes. Here we aim to achieve an artificial system that "records" the temp. changes in the environment with the concurrent LP formation. We first illustrate the differences in 1-D LPs developing at different temps. in terms of band spacings, which can demonstrate the time, ramp steepness, and extent of a temp. change. These results are discussed and augmented by a math. model. Using SEM, we show that the av. size of the CuCrO4 ppt. also reflects the temp. changes. Finally, we show that these changes can also be "recorded" in the 2-D and 3-D LPs, which can have applications in long-term temp. tracking and complex soft material design.
      >> More from SciFinder ®
      https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BB38Xhtl2htrc%253D&md5=2ba1658179a6847e06819a049e6057b9
    31. 31
      Lagzi, I.; Kármán, D. Equidistant Precipitate Pattern Formation Behind a Propagating Chemical Front. Chem. Phys. Lett. 2003, 372, 831– 835,  DOI: 10.1016/S0009-2614(03)00524-4
      31
      Equidistant precipitate pattern formation behind a propagating chemical front
      Lagzi, Istvan; Karman, Daniel
      Chemical Physics Letters (2003), 372 (5,6), 831-835CODEN: CHPLBC; ISSN:0009-2614. (Elsevier Science B.V.)
      Formation of one- and two-dimensional equidistant ppt. patterns due to the coupling of an autocatalytic chem. front with a pptn. reaction was studied numerically. A simple six-variable model based on a cubic autocatalytic reaction has been defined and investigated, where the pptn. step contained a diffusive intermediary species. Simulations show that such a hypothetical reaction-diffusion system can lead to formation of equidistantly striped or more complex patterns.
      >> More from SciFinder ®
      https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD3sXjsVeltro%253D&md5=467e8fe4cd229d69132d7fb9c10f2efb
    32. 32
      Bena, I.; Droz, M.; Lagzi, I.; Martens, K.; Rácz, Z.; Volford, A. Designed Patterns: Flexible Control of Precipitation through Electric Currents. Phys. Rev. Lett. 2008, 101, 075701  DOI: 10.1103/PhysRevLett.101.075701
      32
      Designed Patterns: Flexible Control of Precipitation through Electric Currents
      Bena, I.; Droz, M.; Lagzi, I.; Martens, K.; Racz, Z.; Volford, A.
      Physical Review Letters (2008), 101 (7), 075701/1-075701/4CODEN: PRLTAO; ISSN:0031-9007. (American Physical Society)
      Understanding and controlling pptn. patterns formed in reaction-diffusion processes is of fundamental importance with high potential for tech. applications. Here we present a theory showing that pptn. resulting from reactions among charged agents can be controlled by an appropriately designed, time-dependent elec. current. Examples of current dynamics yielding periodic bands of prescribed wavelength, as well as more complicated structures are given. The pattern control is demonstrated exptl. using the reaction-diffusion process 2AgNO3 + K2Cr2O7→Ag2Cr2O7 + 2KNO3.
      >> More from SciFinder ®
      https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD1cXhtVSisb%252FP&md5=c53dbedb22874b6de4df77abb7b7bc0f
    33. 33
      Dash, U. N. Solute–solvent Interactions and Dissolution of Some Sparingly Soluble Silver Salts in Various Solvent Systems. Fluid Phase Equilib. 1981, 5, 323– 336,  DOI: 10.1016/0378-3812(80)80064-1
      33
      Solute-solvent interactions and dissolution of some sparingly soluble silver salts in various solvent systems
      Dash, Upendra N.
      Fluid Phase Equilibria (1981), 5 (3-4), 323-36CODEN: FPEQDT; ISSN:0378-3812.
      The values for the soly. products of Ag salts in aq., non-aq., and mixed solvent systems were collected and analyzed in the light of electrostatic as well as solute-solvent interaction effects on the dissoln. processes of Ag salts. Std. Gibbs transfer energies derived from the change in the soly. product value were also examd. Solute-solvent interactions rather than electrostatic effects assocd. with the change in dielec. const. are largely responsible for the changes in the value of soly. product with the compn. of the solvent mixts.
      >> More from SciFinder ®
      https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaL3MXptFalsA%253D%253D&md5=b63c31ac60266674b70ceed66e66e14b
    34. 34
      Dash, U. N.; Pattanaik, E.; Sahu, R. Solute-solvent Interactions: Dissolution of Sparingly Soluble Silver Salts in Aqueous-organic Solvent Systems. Fluid Phase Equilib. 1991, 63, 101– 110,  DOI: 10.1016/0378-3812(91)80023-O
      34
      Solute-solvent interactions: dissolution of sparingly soluble silver salts in aqueous-organic solvent systems
      Dash, Upendra; Pattanaik, Ellarani; Sahu, Renuka
      Fluid Phase Equilibria (1991), 63 (1-2), 101-10CODEN: FPEQDT; ISSN:0378-3812.
      The solubilities of the salts Ag2X (where X is sulfate, chromate, tungstate, dichromate, oxalate, malonate, succinate, glutarate or adipate) and Ag,Y (where Y is phosphate or arsenate) were detd. in various compns. of water + dioxane (5-20 wt.%), water + urea (11.52-36.83 wt.%), water + mannitol (5 wt.%) and water + sorbitol (5 wt.%) mixts. at different temps. The soly. data are discussed in the light of electrostatic as well as solute-solvent interaction effects on the dissoln. processes of the silver salts. Std. transfer thermodn. quantities derived from the change in the soly. product are also examd.
      >> More from SciFinder ®
      https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaK3MXktlKmsr0%253D&md5=c14fb2493f78cc2a5e0e9ef754af4aaf
    35. 35
      Humayun, H. Y.; Shaarani, M. N. N. M.; warrior, A.; Abdullah, B.; Salam, M. A. The Effect of Co-solvent on the Solubility of a Sparingly Soluble Crystal of Benzoic Acid. Procedia Eng. 2016, 148, 1320– 1325,  DOI: 10.1016/j.proeng.2016.06.548
      35
      The Effect of Co-solvent on the Solubility of a Sparingly Soluble Crystal of Benzoic Acid
      Humayun, Hudzaifah Yousuf; Shaarani, M. Nizamuddin N. M.; Warrior, Ali; Abdullah, Bawadi; Salam, Md. Abdus
      Procedia Engineering (2016), 148 (), 1320-1325CODEN: PERNBE; ISSN:1877-7058. (Elsevier Ltd.)
      The Benzoic acid is widely used in the pharmaceutical industry, plasticizers and food preservative which show low aq. soly. and dissoln. rate. The investigation has been made to improve the soly. of benzoic acid by using co-solvent. The co-solvent soln. is prepd. by using glycerol in water by vol. ratio. The result shows the relation between soly. in different co-solvent and temp. whereby as the percentage of glycerol increase, the soly. of benzoic acid increase. A similartrend was depicted in term of soly. relation with temp. as the temp. increase amt. of benzoic acid dissolved also increase. Thermodn. dissocn. const., pKa are directly proportional totemperature between 30oC and 90oC. Enthalpy and entropy change of the dissocn. process are 2.907 kJ/mol and -24.09 J/mol resp. Gibbs free energy of dissocn. at 30oC, 60oC and 90oC are -4.390 KJ/mol, -5.114 KJ/mol and 5.837 KJ/mol resp. depicted that the soly. increased with temp.
      >> More from SciFinder ®
      https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC28Xht1Siu73P&md5=09f53b4110b2db58d50b425a583d9a9c
    36. 36
      Dembek, M.; Bocian, S.; Buszewski, B. Solvent Influence on Zeta Potential of Stationary Phase─Mobile Phase Interface. Molecules 2022, 27, 968  DOI: 10.3390/molecules27030968
      36
      Solvent Influence on Zeta Potential of Stationary Phase-Mobile Phase Interface
      Dembek, Mikolaj; Bocian, Szymon; Buszewski, Boguslaw
      Molecules (2022), 27 (3), 968CODEN: MOLEFW; ISSN:1420-3049. (MDPI AG)
      Zeta potential is a surface characteristic formed on the solid surface and liq. interface. It is an interesting way to describe the surface properties of materials; thus, a series of four homemade polar embedded stationary phases that contain phosphate groups incorporated into hydrophobic ligands were investigated according to surface zeta potential. Measurements were carried out using Zetasizer Nano ZS for the stationary phases suspensions prepd. in various solvent and solvent binary mixts. The neg. zeta potential values were obtained for most cases due to neg. charged residual silanols and phosphate groups. However, in some solvents: THF, isopropanol, and toluene zeta potential are pos. Addnl., it was obsd. that the zeta potential seems to be independent of the type of silica gel used for the stationary phase synthesis.
      >> More from SciFinder ®
      https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BB38XktFahtLY%253D&md5=2be4b7787a82037cfb3c4528e32df6a7
    37. 37
      Lyklema, J. Principles of the Stability of lyophobic Colloidal Dispersions in Non-aqueous Media. Adv. Colloid Interface Sci. 1968, 2, 67– 114,  DOI: 10.1016/0001-8686(68)85001-8
      There is no corresponding record for this reference.
    38. 38
      Płowaś, I.; Świergiel, J.; Jadżyn, J. Relative Static Permittivity of Dimethyl Sulfoxide + Water Mixtures. J. Chem. Eng. Data 2013, 58, 1741– 1746,  DOI: 10.1021/je400149j
      38
      Relative Static Permittivity of Dimethyl Sulfoxide + Water Mixtures
      Plowas, Iwona; Swiergiel, Jolanta; Jadzyn, Jan
      Journal of Chemical & Engineering Data (2013), 58 (6), 1741-1746CODEN: JCEAAX; ISSN:0021-9568. (American Chemical Society)
      The dielec. spectra corresponding to the static regime of DMSO + water mixts. were recorded in the whole concn. range and in the temp. range from (253.15 to 333.15) K. For the mixts. rich in DMSO (0.60 < xDMSO ≤ 1, x = mole fraction) and rich in water (0 ≤ xDMSO < 0.1), it was possible to perform the investigations both in the liq. and solid phases of the samples. The detd. melting temps. were compared to the data available in the literature. The deviation from the additivity of the measured static permittivity of DMSO + water mixts. shows a max. for xDMSO ≈ 0.35, indicating formation at that concn. of intermol. entities (most probably they are 1DMSO·2H2O hydrogen-bonded complexes) of a relatively enhanced polarity.
      >> More from SciFinder ®
      https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3sXnvVCqu78%253D&md5=21109d4578e5b052d8b285676c7fe7bd
    39. 39
      Dee, G. T. Patterns Produced by Precipitation at a Moving Reaction Front. Phys. Rev. Lett. 1986, 57, 275– 278,  DOI: 10.1103/PhysRevLett.57.275
      39
      Patterns produced by precipitation at a moving reaction front
      Dee, G. T.
      Physical Review Letters (1986), 57 (3), 275-8CODEN: PRLTAO; ISSN:0031-9007.
      Many pptn. patterns are assocd. with the formation of a sparingly sol. product at a moving reaction front. A model is introduced which describes the transport, reaction, nucleation, and droplet-growth kinetics of the processes involved. The rapid change in the nucleation rate as a function of the supersatn. is essential for pattern formation. The model allows the correlation details of the patterns with the various kinetic processes.
      >> More from SciFinder ®
      https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaL28XkvVGrt7g%253D&md5=760a5f33ad36090cbc0c9fd28462b8f9
    40. 40
      Krug, H.-J.; Brandtstädter, H. Morphological Characteristics of Liesegang Rings and Their Simulations. J. Phys. Chem. A 1999, 103, 7811– 7820,  DOI: 10.1021/jp991092l
      40
      Morphological Characteristics of Liesegang Rings and Their Simulations
      Krug, Hans-Juergen; Brandtstaedter, Hermann
      Journal of Physical Chemistry A (1999), 103 (39), 7811-7820CODEN: JPCAFH; ISSN:1089-5639. (American Chemical Society)
      Numerical simulations of Liesegang systems are performed both with a prenucleation and a postnucleation model. Special interest is dedicated to 2-dimensional morphol. peculiarities of ring systems. With the prenucleation model, apparent bifurcations or branch points (anastomoses) can be created by adjacent trains of bands having different interband spaces or band positions shifted to each other. Spiral systems arise when the circular symmetry of concentric Liesegang rings is broken by at least one branch point. The postnucleation model comprises both formation of colloidal particles which form a turbidity zone and transition of these nuclei to solid particles which undergo Ostwald ripening at the expense of the colloids. The model demonstrates how Liesegang bands of solid particles arise from a primary turbidity zone which surrounds the expanding ring system. Because of rapid competitive particle growth, rings or bands may no longer grow continuously in transversal directions. They become arranged in chains of single filaments or spots forming a transversal rhythm. Finally, longitudinal alleys of gaps appear in continuous trains of Liesegang bands.
      >> More from SciFinder ®
      https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaK1MXlslOntLY%253D&md5=8c4bf9b11c817ac61fd270e94be99435
    41. 41
      Pan, C.; Gao, Q.; Xie, J.; Xia, Y.; Epstein, I. R. Precipitation Patterns with Polygonal Boundaries Between Electrolytes. Phys. Chem. Chem. Phys. 2009, 11, 11033– 11039,  DOI: 10.1039/b904445k
      41
      Precipitation patterns with polygonal boundaries between electrolytes
      Pan, Changwei; Gao, Qingyu; Xie, Jingxuan; Xia, Yu; Epstein, Irving R.
      Physical Chemistry Chemical Physics (2009), 11 (46), 11033-11039CODEN: PPCPFQ; ISSN:1463-9076. (Royal Society of Chemistry)
      Two-dimensional Liesegang patterns formed when the boundary between electrolytes is polygonal display a variety of patterns, such as dislocations (radial alleys of gaps), branches (anastomoses) and spirals, many of which can be found in nature. Each vertex of the polygon can produce a pair of dislocation lines or branch lines. The effect caused by a vertex decreases with the no. of vertices. Double-armed spirals are obsd. in expts. with a pentagonal boundary. Hexagons, which begin to approach smooth circular boundaries, do not give rise to dislocations, but instead yield concentric pptn. rings. A simple model of nucleation growth enables us to simulate dislocations and spirals consistent with those seen in our expts.
      >> More from SciFinder ®
      https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD1MXhsVentrfJ&md5=bd2b666249589e4d449b273dfa36ea68
    42. 42
      Kumbharkhane, A. C.; Puranik, S. M.; Mehrotra, S. C. Dielectric Relaxation Studies of Aqueous N,N-dimethylformamide Using a Picosecond Time Domain Technique. J. Solution Chem. 1993, 22, 219– 229,  DOI: 10.1007/BF00649245
      42
      Dielectric relaxation studies of aqueous N,N-dimethylformamide using a picosecond time domain technique
      Kumbharkhane, A. C.; Puranik, S. M.; Mehrotra, S. C.
      Journal of Solution Chemistry (1993), 22 (3), 219-29CODEN: JSLCAG; ISSN:0095-9782.
      The dielec. relaxation studies of DMF at 13 concn. in aq. solns. were carried out by using a time-domain reflectometry technique in the frequency range from 10 MHz to 10 GHz. The dielec. parameters and excess dielec. properties also were detd. at 5-40°. The Luzar theory was applied to compute the cross correlation terms for the mixt. It adequately reproduces the exptl. values of the static dielec. consts. The Bruggeman model for the nonlinear case was fitted to the dielec. data for mixts.
      >> More from SciFinder ®
      https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaK3sXitVehs78%253D&md5=942800a9fd62143a47a637d4dc65b020
    43. 43
      Zahn, M.; Ohki, Y.; Fenneman, D. B.; Gripshover, R. J.; Gehman, V. H. Dielectric Properties of Water and Water/ethylene Glycol Mixtures for Use in Pulsed Power System Design. Proc. IEEE 1986, 74, 1182– 1221,  DOI: 10.1109/PROC.1986.13611
      43
      Dielectric properties of water and water/ethylene glycol mixtures for use in pulsed power system design
      Zahn, Markus; Ohki, Yoshimichi; Fenneman, David B.; Gripshover, Ronald J.; Gehman, Victor H., Jr.
      Proceedings of the IEEE (1986), 74 (9), 1182-221CODEN: IEEPAD; ISSN:0018-9219.
      A review with 176 refs. with emphasis on dielec. const., breakdown strength, and relaxation time.
      >> More from SciFinder ®
      https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaL28XmtVWisL8%253D&md5=a7369b346d3d17aeb4759259d7d10ab4
    44. 44
      Kumbharkhane, A. C.; Puranik, S. M.; Mehrotra, S. C. Dielectric Relaxation of Tert-butyl Alcohol–water Mixtures Using a Time-domain Technique. J. Chem. Soc., Faraday Trans. 1991, 87, 1569– 1573,  DOI: 10.1039/FT9918701569
      44
      Dielectric relaxation of tert-butyl alcohol-water mixtures using a time-domain technique
      Kumbharkhane, Ashok C.; Puranik, Sanjay M.; Mehrotra, Suresh C.
      Journal of the Chemical Society, Faraday Transactions (1991), 87 (10), 1569-73CODEN: JCFTEV; ISSN:0956-5000.
      Dielec. relaxation measurements in the frequency range 10 MHz-10 GHz have been carried out in tert-Bu alc.-water mixts. with various concns. over the temp. range 273-313 K using a time-domain reflectometry (TDR) method. The bilinear calibration method as suggested by Cole has been used to correct the permittivity spectra. The cor. spectra could be fitted with a single relaxation time with a small amt. of Cole-Davidson behavior. Deviations from ideal mixing behavior in the permittivity parameter (ε0-ε∞) and relaxation time (τ) suggested the formation of a polymeric structure in tert-Bu alc.-water mixts. The dielec. relaxation behavior showed the same structural changes as obsd. in ultrasonic relaxation. However, the max. in excess permittivity and excess relation time occurred at different positions. This could not be explained by a simple model of the polymeric structure.
      >> More from SciFinder ®
      https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaK3MXktl2rtL4%253D&md5=ee610aa2fdb9df46c67d02ada7973c2a
    45. 45
      Sonnati, M. O.; Amigoni, S.; Taffin de Givenchy, E. P.; Darmanin, T.; Choulet, O.; Guittard, F. Glycerol Carbonate as a Versatile Building Block for Tomorrow: Synthesis, Reactivity, Properties and Applications. Green Chem. 2013, 15, 283– 306,  DOI: 10.1039/C2GC36525A
      45
      Glycerol carbonate as a versatile building block for tomorrow: synthesis, reactivity, properties and applications
      Sonnati, Matthieu O.; Amigoni, Sonia; Taffin de Givenchy, Elisabeth P.; Darmanin, Thierry; Choulet, Olivier; Guittard, Frederic
      Green Chemistry (2013), 15 (2), 283-306CODEN: GRCHFJ; ISSN:1463-9262. (Royal Society of Chemistry)
      A review. The synthesis, reactivity and applications of glycerol carbonate (glycerin carbonate or 4-hydroxymethyl-2-oxo-1,3-dioxolane) are discussed and reviewed. Supported by the increasing sustainable awareness, glycerol carbonate has gained much interest over the last 20 years because of its versatile reactivity and as a way to valorize waste glycerol. Numerous synthesis pathways for this mol. were identified, some of them very promising and on the verge of being applied at an industrial scale. The wide reactivity of this mol. due to the presence of both a hydroxyl group and a 2-oxo-1,3-dioxolane group has been studied and has initiated some emerging applications in various domains from solvents to polymers.
      >> More from SciFinder ®
      https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3sXhsVOnt7c%253D&md5=5d6f8a923217cb4507843afa7e5ce35a
    46. 46
      Sarri, F.; Tatini, D.; Tanini, D.; Simonelli, M.; Ambrosi, M.; Ninham, B. W.; Capperucci, A.; Dei, L.; Lo Nostro, P. Specific Ion Effects in Non-aqueous Solvents: the Case of Glycerol Carbonate. J. Mol. Liq. 2018, 266, 711– 717,  DOI: 10.1016/j.molliq.2018.06.120
      46
      Specific ion effects in non-aqueous solvents: The case of glycerol carbonate
      Sarri, Filippo; Tatini, Duccio; Tanini, Damiano; Simonelli, Matteo; Ambrosi, Moira; Ninham, Barry W.; Capperucci, Antonella; Dei, Luigi; Lo Nostro, Pierandrea
      Journal of Molecular Liquids (2018), 266 (), 711-717CODEN: JMLIDT; ISSN:0167-7322. (Elsevier B.V.)
      The effect of eight potassium salts (KF, K3PO4, KOCN, K2CO3, KCl, K2SO4, KBr and KI) on glycerol carbonate (GC) is studied through NMR, DSC, soly. and ATR-FTIR expts. From the soly. data, the main thermodn. functions of soln. and solvation are estd., and the mean molal activity coeffs. are calcd. The results suggest that the capability of an anion to establish hydrogen bonds with the solvent mols. (or behave as a base, as in the case of fluoride, phosphate, cyanate and carbonate) is the most important structural feature that dets. its effects on the solvent structure. On the other hand potassium iodide behaves in an anomalous way, due to the large polarizability of the anion that can form non-electrostatic, van der Waals dispersive intermol. interactions.
      >> More from SciFinder ®
      https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC1cXht12ju7vI&md5=e849a4fca7bf75bf742d8cb7a390dc5f
    47. 47
      Valletti, N.; Acar, M.; Cucciniello, R.; Magrini, C.; Budroni, M. A.; Tatini, D.; Proto, A.; Marchettini, N.; Lo Nostro, P.; Rossi, F. Glycerol Carbonate Structuring in Aqueous Solutions as Inferred from Mutual Diffusion Coefficient, Density and Viscosity Measurements in the Temperature Range 283.15–313.15 K. J. Mol. Liq. 2022, 357, 119114  DOI: 10.1016/j.molliq.2022.119114
      47
      Glycerol carbonate structuring in aqueous solutions as inferred from mutual diffusion coefficient, density and viscosity measurements in the temperature range 283.15-313.15 K
      Valletti, Nadia; Acar, Mert; Cucciniello, Raffaele; Magrini, Claudia; Budroni, Marcello A.; Tatini, Duccio; Proto, Antonio; Marchettini, Nadia; Lo Nostro, Pierandrea; Rossi, Federico
      Journal of Molecular Liquids (2022), 357 (), 119114CODEN: JMLIDT; ISSN:0167-7322. (Elsevier B.V.)
      Glycerol Carbonate (4-hydroxymethyl-2-oxo-1,3-dioxolane, GC) is an emerging green reactant for many org. chem. applications. GC popularity stems from its high reactivity, which makes it attractive for many chem. transformations and for its easy synthesis from glycerol, a byproduct of biodiesel prodn. While extensive literature covers the synthesis and chem. reactivity of GC, its transport properties are poorly studied, esp. in water. Here, we measured for the first time the diffusion coeff. of GC in water in the temp. range 283.15-313.15 K and for concns. up to 0.1 M. By taking advantage of the Taylor Dispersion Anal. (TDA) we found D0 = 9.53±0.06 x 10-10 m2/s at 298.15 K and an activation energy for the diffusion process Ea = 3.74±0.09 kcal/mol. D. and dynamic viscosity were also measured in the same temp. interval to calc. the hydrodynamic radius of GC. Exptl. data helped in assessing the structure of GC aggregates formed in aq. solns. and provided an estn. of the equil. const. for the dimer formation. Our findings can be useful for studying the fate of GC in the environment and to improve its use for applications in aq. media.
      >> More from SciFinder ®
      https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BB38XhtValu7%252FM&md5=62347cb3d2d851927657db42a3f1f1f0
    48. 48
      Droz, M.; Magnin, J.; Zrinyi, M. Liesegang Patterns: Studies on the Width Law. Chem. Phys. 1999, 110, 9618– 9622,  DOI: 10.1063/1.478927
      48
      Liesegang patterns: Studies on the width law
      Droz, M.; Magnin, J.; Zrinyi, M.
      Journal of Chemical Physics (1999), 110 (19), 9618-9622CODEN: JCPSA6; ISSN:0021-9606. (American Institute of Physics)
      The so-called width law for Liesegang patterns, which states that the positions xn and widths wn of bands verify the relation xn∼wnα for some α>0, is investigated both exptl. and theor. We provide exptl. data exhibiting good evidence for values of α close to 1. The value α=1 is supported by theor. arguments based on a generic model of reaction diffusion.
      >> More from SciFinder ®
      https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaK1MXislOju7Y%253D&md5=0f0082741a49c1afd087425c31cbf74c
    49. 49
      Rácz, Z. Formation of Liesegang Patterns. Phys. A 1999, 274, 50– 59,  DOI: 10.1016/S0378-4371(99)00432-X
      49
      Formation of Liesegang patterns
      Racz, Zoltan
      Physica A: Statistical Mechanics and Its Applications (Amsterdam) (1999), 274 (1-2), 50-59CODEN: PHYADX; ISSN:0378-4371. (Elsevier Science B.V.)
      It has been recently shown that pptn. bands characteristic of Liesegang patterns emerge from spinodal decompn. of reaction products in the wake of moving reaction fronts. This mechanism explains the geometric sequence of band positions xn ∼ Q(1 + p)n and, furthermore, it yields a spacing coeff. p that is in agreement with the exptl. obsd. Matalon-Packter law. Here I examine the assumptions underlying this theory and discuss the choice of input parameters that leads to exptl. observable patterns. I also show that the so-called width law relating the position and the width of the bands wn ∼ xn follows naturally from this theory.
      >> More from SciFinder ®
      https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD3cXnt1Cksg%253D%253D&md5=c1adaa1530961dfdb957cfa23a93fb22
    50. 50
      Israelachvili, J. N. Intermolecular and Surface Forces; Academic Press: Cambridge, Massachusetts, United States, 2011.
      There is no corresponding record for this reference.
    51. 51
      Nabika, H.; Sato, M.; Unoura, K. Liesegang Patterns Engineered by a Chemical Reaction Assisted by Complex Formation. Langmuir 2014, 30, 5047– 5051,  DOI: 10.1021/la5003786
      51
      Liesegang Patterns Engineered by a Chemical Reaction Assisted by Complex Formation
      Nabika, Hideki; Sato, Mami; Unoura, Kei
      Langmuir (2014), 30 (18), 5047-5051CODEN: LANGD5; ISSN:0743-7463. (American Chemical Society)
      Liesegang rings based on a chem. reaction, not a conventional pptn. reaction, have been developed by appropriate design of the nucleation dynamics in a system involving complex formation in a matrix. The periodic and concentric rings consisted of well-dispersed Ag nanoparticles with diams. of a few nanometers. The approach modeled here could be applied to form novel micropatterns out of inorg. salts, metal nanoparticles, org. nanocrystals, or polymeric fibers, and it could also offer a scaffold for novel models of a wide variety of reaction-diffusion phenomena in nature.
      >> More from SciFinder ®
      https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2cXmvFequrc%253D&md5=66d5ada9ac5ccc1ce509933172561443
    52. 52
      Walliser, R. M.; Boudoire, F.; Orosz, E.; Tóth, R.; Braun, A.; Constable, E. C.; Rácz, Z.; Lagzi, I. Growth of Nanoparticles and Microparticles by Controlled Reaction-diffusion Processes. Langmuir 2015, 31, 1828– 1834,  DOI: 10.1021/la504123k
      52
      Growth of Nanoparticles and Microparticles by Controlled Reaction-Diffusion Processes
      Walliser, Roche M.; Boudoire, Florent; Orosz, Eszter; Toth, Rita; Braun, Artur; Constable, Edwin C.; Racz, Zoltan; Lagzi, Istvan
      Langmuir (2015), 31 (5), 1828-1834CODEN: LANGD5; ISSN:0743-7463. (American Chemical Society)
      The synthesis of different sizes of nanoparticles and microparticles is important in designing nanostructured materials with various properties. Wet synthesis methods lack the flexibility to create various sizes of particles (particle libraries) using fixed conditions without the repetition of the steps in the method with a new set of parameters. Here, the authors report a synthesis method based on nucleation and particle growth in the wake of a moving chem. front in a gel matrix. The process yields well-sepd. regions (bands) filled with nearly monodisperse nanoparticles and microparticles, with the size of the particles varying from band to band in a predictable way. The origin of the effect is due to an interplay of a pptn. reaction of the reagents and their diffusion that is controlled in space and time by the moving chem. front. The method represents a new approach and a promising tool for the fast and competitive synthesis of various sizes of colloidal particles.
      >> More from SciFinder ®
      https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2MXmvFSjsw%253D%253D&md5=8d3e7be0888082a7b1a83dfeb7eee97c
    53. 53
      Moncure, P. J.; Simon, Z. C.; Millstone, J. E.; Laaser, J. E. Relationship between Gel Mesh and Particle Size in Determining Nanoparticle Diffusion in Hydrogel Nanocomposites. J. Phys. Chem. B 2022, 126, 4132– 4142,  DOI: 10.1021/acs.jpcb.2c00771
      53
      Relationship between Gel Mesh and Particle Size in Determining Nanoparticle Diffusion in Hydrogel Nanocomposites
      Moncure, Paige J.; Simon, Zoe C.; Millstone, Jill E.; Laaser, Jennifer E.
      Journal of Physical Chemistry B (2022), 126 (22), 4132-4142CODEN: JPCBFK; ISSN:1520-5207. (American Chemical Society)
      The diffusion of poly(ethylene glycol) Me ether thiol (PEGSH)-functionalized gold nanoparticles (NPs) was measured in polyacrylamide gels with various crosslinking densities. The mol. wt. of the PEGSH ligand and particle core size were both varied to yield particles with hydrodynamic diams. ranging from 7 to 21 nm. The gel mesh size was varied from approx. 36 to 60 nm by controlling the crosslinking d. of the gel. Because high-mol.-wt. ligands are expected to yield more compressible particles, we expected the diffusion consts. of the NPs to depend on their hard/soft ratios (where the hard component of the particle consists of the particle core and the soft component of the particle consists of the ligand shell). However, our measurements revealed that NP diffusion coeffs. resulted primarily from changes in the overall hydrodynamic diam. and not the ratio of particle core size to ligand size. Across all particles and gels, we found that the diffusion coeff. was well predicted by the confinement ratio calcd. from the diam. of the particle and an est. of the gel mesh size obtained from the elastic blob model and was well described using a hopping model for nanoparticle diffusion. These results suggest that the elastic blob model provides a reasonable est. of the mesh size that particles "see" as they diffuse through the gel. This work brings new insights into the factors that dictate how NPs move through polymer gels and will inform the development of hydrogel nanocomposites for applications such as drug delivery in heterogeneous, viscoelastic biol. materials.
      >> More from SciFinder ®
      https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BB38XhtlCmt7bO&md5=2efe23e7cf35d7340941fe18f90389e5
    54. 54
      Jiang, J.; Sakurai, K. Formation of Ultrathin Liesegang Patterns. Langmuir 2016, 32, 9126– 9134,  DOI: 10.1021/acs.langmuir.6b02148
      54
      Formation of Ultrathin Liesegang Patterns
      Jiang, Jinxing; Sakurai, Kenji
      Langmuir (2016), 32 (36), 9126-9134CODEN: LANGD5; ISSN:0743-7463. (American Chemical Society)
      Liesegang patterns (LPs) have been prepd. in nanofilms 65 nm thick. The key parameters are temp. control and the introduction of equil. water vapor in the sample environment. Atomic force microscope images clearly showed that the LPs are composed of 300-600 nm laterally coagulated particles. The densities and thicknesses of the ultrathin films were evaluated by X-ray reflectivity. During the present research, new patterns, which are different from ordinary LPs, have been discovered for the first time in the outermost part of the whole pattern. Studying LPs in ultrathin films may help to forge a better understanding of the mechanism underlying the intriguing phenomenon.
      >> More from SciFinder ®
      https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC28XhtlajtrzF&md5=b96f4b2b1317b35ade9722ca407fbde5
    55. 55
      Farkas, S.; Fonyi, M. S.; Holló, G.; Német, N.; Valletti, N.; Kukovecz, Á.; Schuszter, G.; Rossi, F.; Lagzi, I. Periodic Precipitation of Zeolitic Imidazolate Frameworks in a Gelled Medium. J. Phys. Chem. C 2022, 126, 9580– 9586,  DOI: 10.1021/acs.jpcc.2c02371
      55
      Periodic Precipitation of Zeolitic Imidazolate Frameworks in a Gelled Medium
      Farkas, Szabolcs; Fonyi, Mate Sandor; Hollo, Gabor; Nemet, Norbert; Valletti, Nadia; Kukovecz, Akos; Schuszter, Gabor; Rossi, Federico; Lagzi, Istvan
      Journal of Physical Chemistry C (2022), 126 (22), 9580-9586CODEN: JPCCCK; ISSN:1932-7447. (American Chemical Society)
      Formation of spatially periodic patterns is a ubiquitous process in nature and man-made systems. Periodic pptn. is the oldest type of pattern formation, in which the formed colloid particles are self-assembled into a sequence of spatially sepd. pptn. zones in solid hydrogels. Chem. systems exhibiting periodic pptn. mostly comprise oppositely charged inorg. ions. Here, we present a new sub-group of this phenomenon driven by the diffusion and reaction of several transition metal cations (Zn2+, Co2+, Cd2+, Cu2+, Fe2+, Mn2+, and Ni2+) with an org. linker (2-methylimidazole) producing periodic pptn. of zeolitic imidazolate frameworks. In some cases, the formed crystals reached the size of ∼50μm showing that a gel matrix can provide optimal conditions for nucleation and crystal growth. We investigated the effect of the gel concn. and solvent compn. on the morphol. of the pattern. To support the exptl. observations, we developed a reaction-diffusion model, which qual. describes the spatially periodic pattern formation.
      >> More from SciFinder ®
      https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BB38XhtlCmtLzF&md5=660693f7af88f633d7ae61fc85f70bb5

  • Supporting Information

    Supporting Information

    The Supporting Information is available free of charge at https://pubs.acs.org/doi/10.1021/acs.jpcb.2c05810.

    • Procedures for the synthesis of GC, solubility product (Ksp) measurements, and line profile analysis, detail of numerical simulation and model; results of optical microscopy observations, time-course, pattern formation with organic solvents (DMF, EG, TBA, GL, and GC), line profile, spacing coefficient, DLS, and ζ potential measurements, Ksp measurements, diffusion of Cu2+, and simulations (PDF)


    Terms & Conditions

    Most electronic Supporting Information files are available without a subscription to ACS Web Editions. Such files may be downloaded by article for research use (if there is a public use license linked to the relevant article, that license may permit other uses). Permission may be obtained from ACS for other uses through requests via the RightsLink permission system: http://pubs.acs.org/page/copyright/permissions.html.