
The Science and Function of Nanomaterials: From Synthesis to Application
Title, Copyright, Foreword
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Preface
Amanda S. Harper-Leatherman - and
Camille M. Solbrig
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Nanomaterial Synthesis and Functionalization
Fructose as a Precursor for Mesoporous Carbon: Straightforward Solvent-Free Synthesis by Nanocasting
C. Weinberger - ,
S. Haffer - ,
T. Wagner - , and
M. Tiemann
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Due to their unique properties, ordered mesoporous carbon (OMC) materials prepared by nanocasting have raised great attention in recent years. Their synthesis usually comprises multiple cycles of impregnating a porous structure matrix with an aqueous solution of a suitable precursor, such as sucrose or other, often hazardous, compound. We present a more straightforward variation of this method by using fructose as the precursor compound. By using a solvent-free melt of the precursor, the impregnation requires only a single step. After carbonization by thermal decomposition and removal of the mesoporous silica structure matrix (SBA-15), ordered mesoporous carbon with one (CMK-3) or two (CMK-5) pore modes in two-dimensional, hexagonal symmetry (p6mm) is obtained.
Chemical Beam Epitaxy of Gallium Nitride Nanowires
Ryan A. Munden - and
Mark A. Reed
Semiconductor nanowires have become a field of intense investigation in the pursuit of bottom-up materials and their devices; they will continue to scale in size, while offering new capabilities in fields such as computation, optoelectronics, biosensing, and photovoltaics. Semiconducting nanowires have been grown using a variety of techniques. The most common method, hot-wall chemical vapor deposition (CVD), has been successfully used to grow a variety of semiconductor nanowire materials. Extensive investigation of statistically significant numbers of gallium nitride (GaN) nanowires grown by hot-wall CVD has shown that these nanowires have low mobilities (~1 cm2V-1s-1) and high carrier concentrations (~1018 cm-3). In essence, hot-wall CVD growth occurs near equilibrium conditions and does not permit easy tuning of the parameters of the nanowire growth to achieve the desired electronic characteristics. Growth of GaN nanowires has been achieved using the chemical beam epitaxy method (CBE). CBE is a non-equilibrium growth technique that grows material in a high vacuum with all gas-source precursors. This enables control of precursor delivery, independent of the growth temperature. Initial results demonstrate aligned nanowire growth, but that is dominated by self-catalyzed growth of nanowires, as opposed to metal catalyst mediated growth via the Vapor-Liquid-Solid (VLS) method. The CBE opens up the possibility of growing compound semiconductor nanowires with repeatable and controllable characteristics.
Reversible Graphene Functionalization for Electronic Applications: A Review
Keith E. Whitener Jr.,
Covalent attachment of various functional groups to the surface of graphene is a straightforward way to modify its electronic properties. A considerable number of chemical reactions have been developed on graphene, most of which result in permanent modification of the structure of graphene. However, a subset of these reactions are reversible, so that the properties of pristine graphene can be restored. Reversibility of functionalization on graphene has important implications for device design and circuit patterning. Different functionalities change the electronic properties of graphene in different ways, and patterning pristine graphene in a functionalized graphene matrix yields devices with interesting electronic properties. In this review, we examine several partially and fully reversible graphene reactions and their effects on graphene’s electronic properties. We also detail useful applications for these reversible reactions.
Synthesis of Single-Walled Carbon Nanotube−Nanoparticle Hybrid Structures
Tirandai Hemraj-Benny
In this chapter, we explore chemical strategies for the functionalization of single-walled carbon nanotube (SWNT) surfaces with metal nanoparticles reported in the past decade. The preparation of SWNT-metal nanoparticle hybrid materials is an important research area as the new hybrid materials generated possess unique properties and are useful for various nanotechnological applications. These hybrids can be stabilized by covalent and/or noncovalent interactions. Although covalent interactions between the sidewalls, ends and defect sites of SWNTs and nanoparticles are reviewed, the main focus of this chapter is to provide a summary of recently synthesized SWNT-nanoparticle hybrids via noncovalent interactions.
Nanomaterial Applications
Multifunctional Nanoparticles in Radiation Oncology: An Emerging Paradigm
Jodi E. Belz - ,
Wilfred Ngwa - ,
Houari Korideck - ,
Robert A. Cormack - ,
Ross Berbeco - ,
Mike Makrigiorgos - ,
Srinivas Sridhar - , and
Rajiv Kumar
The parallel advances in the field of radiation oncology and nanotechnology have created a paradigm changing opportunity to improve the therapeutic outcome in oncology. The integration of nanomedicine in clinical oncology has led to the appreciation of the use of ‘theranostic nanoparticles’ in not only understanding various biological mechanisms associated with cancer, but also in successfully targeting these pathways to modulate the efficacy of treatment. This chapter focuses on the application of various nanoparticle-based formulations to improve radiation therapy. The emphasis is on the functionality of nanoparticles that can modulate the tumor response to radiation, target the molecular pathways, minimize normal tissue toxicities and improve the imaging efficacy for better disease staging and treatment planning. We believe addressing these factors using nanoparticles can shape the future of radiation therapy, facilitating their use towards a personalized medicine approach.
Silver Nanoparticle Films as Hydrogen Sulfide Gas Sensors with Applications in Art Conservation
Rui Chen - and
Paul M. Whitmore
We give a brief review of our research investigating the reaction between silver nanoparticles (Ag NPs) and hydrogen sulfide gas (H2S), developing Ag NP films as H2S gas sensors and examining the applications of Ag NP films in art conservation. The reaction between Ag NPs and H2S demonstrates an initial reaction rate that follows a first-order reaction rate law and is proportional to the 1.3 power of the sulfide gas concentration. This relationship can be used to determine the H2S gas concentration under ambient conditions. Through examination of several applications in art conservation, Ag NP films are shown to not only detect emission of H2S from degraded materials under ambient conditions, but to also substitute for Ag foil and quantify the H2S emission in the Oddy test, which tests materials for their safety in proximity to cultural property.
Development of Calcium Carbonate Double-Coated with Chitosan-Adipic Acid as a Promising Antibacterial Filler
Yecheng He - ,
Baofeng Lin - , and
Haizhong Zou
The aim of the present work was to investigate a new use of chitosan in the modification of calcium carbonate (CaCO3) particles in order to confer specific antibacterial functionality to the particles. Adipic acid was used to introduce carboxyl groups onto the surface of CaCO3 particles. CaCO3 particles double-coated with chitosan-adipic acid (abbreviated as CAC) were prepared through the ionic interaction between the 2 site amino group of chitosan and the carboxyl group of adipic acid. The structure of CAC was characterized by Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA) and scanning electron microscopy (SEM). The zeta potential and contact angle of CAC were studied to evaluate particle interfacial properties. FTIR and TGA analyses showed that chitosan and adipic acid on CAC were combined through electrostatic interactions. When the chitosan concentration was more than 5%, the surface of the CaCO3 particles were coated completely. When chitosan was applied at a 9% concentration to make CAC, the zeta potential increased from –27.58 mV for unmodified particles to +13.11 mV for CAC due to the increased positive charge from chitosan. In a similar way, the specific surface area increased from 2.846 m2/g to 4.709 m2/g, the average particle size decreased from 11.21 μm to 7.49 μm, and the contact angle increased from 0° to 87°. CAC had antibacterial capacity when evaluated with E. coli and S. aureus. The approach in this study provides a method for fabricating chitosan-adipic acid-modified CaCO3 particles, an antibacterial filler for potential applications.
Electrospun Silica Nanofiber Mats
Effects of Sol Viscosity and Application to Thin Layer Chromatography
Abigail Freyer - and
Nancy Ortins Savage
Electrospun nanofiber mats were prepared from low-viscosity sol-gel silica without the addition of a carrier polymer. Silica sols synthesized from tetraethyl orthosilicate (TEOS) under acidic conditions were electrospun into nanofibers in the viscosity range of 2 to 4 mPa·s. The influence of ethanol and water concentrations on the viscosity of as-synthesized and aged silica sols was also determined. Nanofibers produced from as-synthesized sols with a TEOS:H2O ratio of 1:2 ranged in diameter from 50 nm to 200 nm. Increases in viscosity, whether due to aging or increased water concentration in the sol resulted in fragmented nanofibers. Nanofiber mats used as the stationary phase for thin layer chromatography (TLC) were able to separate components of a test dye mixture.
Editors’ Biographies
Subject Index
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