Coassembly of Complementary Polyhedral Metal–Organic Framework Particles into Binary Ordered Superstructures

Here we report the formation of a 3D NaCl-type binary porous superstructure via coassembly of two colloidal polyhedral metal–organic framework (MOF) particles having complementary sizes, shapes, and charges. We employed a polymeric-attenuated Coulombic self-assembly approach, which also facilitated the coassembly of these MOF particles with spherical polystyrene particles to form 2D binary superstructures. Our results pave the way for using MOFs to create sophisticated superstructures comprising particles of various sizes, shapes, porosities, and chemical compositions.


Characterization
All chemical reagents and solvents were used as received without further purification, unless otherwise specified.De-ionized (DI) water was obtained from a Milli-Q water purification system (18.2MΩ•cm).

Instrumentation
Field-emission scanning electron microscopy (FESEM) images were collected on scanning electron microscopes (FEI Magellan 400L XHR and Quanta 650 FEG), using conductive aluminum or copper tape.

Synthesis of TRD-ZIF-8 particles (edge size = 414 ± 17 nm)
TRD-ZIF-8 (edge size = 414 ± 17 nm) was synthesized adapted from a previously described methodology. 2 a typical synthesis, a solution of Zn(CH3COO)2•2H2O (300 mg) in 5 mL of DI water was added into a solution of 1.12 g of 2-MiM and 0.40 mg CTAB in 5 mL of DI water.The resulting mixture was gently stirred for 15 s, causing it to evolve into a white colloidal suspension, which was left undisturbed at room temperature for 2 h.The resulting ZIF-8 particles were washed three times with deionized (DI) water upon centrifugation at 9000 rpm in 50 mL Falcon tubes.ZIF-8 particles (~280 mg) were finally stored as wet pellets.

Synthesis and purification of Pluronic F127-COOH
Pluronic F127-COOH was synthesized according to the previously described methodology.When the functionalization with F127-COOH was done without THF, the zeta potential value of the resulting TRD-ZIF-8 particles was less negative (blue curve) in comparison to that obtained when THF was used.

Figure S5 .
Figure S5.FESEM images of the co-assembly of C-ZIF-8 (edge size = 135 ± 7 nm) and 600 nm-in-diameter spherical PS particles at different NaCl concentrations (2-6 mM).The co-assembly experiments were performed according to the procedure described in Section 2.5, except that the concentration of NaCl was varied from: (a) 2.0 mM; (b) 3.0 mM; (c) 4.0 mM; (d) 5.0 mM; and (e) 6.0 mM.Note here that a concentration of 3.0 mM was chosen as the optimized concentration.Scale bars: 3 µm (a,b,e), and 5 µm (c,d).

Figure S8 .
Figure S8.FESEM images of the assembly of C-ZIF-8 particles (edge size = 135 ± 7 nm) on a preassembled 2D hexagonal arrangement of PS spheres.(a) FESEM images of the pre-assembled 2D hexagonal arrangement of PS spheres.To assemble these spheres, PS particles (82 mg/mL) were dispersed in an aqueous solution containing 0.08 mM F127 and 3 mM NaCl.Then, 25 µL of this colloid were dropped on the glass substrate and dried at 40 °C overnight.(b-d) FESEM images of C-ZIF-8 particles (edge size = 135 ± 7 nm) placed and dried on these hexagonal arrangements of PS spheres.To perform this experiment, C-ZIF-8 particles at different concentrations [0.1 mg/mL (b); 0.5 mg/mL (c); and 1 mg/mL (d)] were dispersed in an aqueous solution containing 0.08 mM F127 and 3 mM NaCl.Then, 15 µL of these colloids were dropped on the PS template, followed by drying at 40 °C overnight.Scale bars: 5 µm (a-d).

Figure S9 .
Figure S9.(a) Size-distribution histogram of TRD-ZIF-8 particles with an edge length φ of 414 ± 17 nm.(b) Size-distribution histogram of the edge of truncated square face of TRD-ZIF-8 with a square face edge length x of 215 ± 15 nm.(c) Scheme and FESEM image of TRD-ZIF-8 particles, highlighting the edge length of particles (φ) and the edge length of the truncated square face (x).Scale bar: 1 μm.

Figure S10. 1 H
Figure S10. 1 H NMR (300 MHz, CDCl3) spectra of F127-COOH.The presence of peaks at around 6.22 and 6.40 ppm are ascribed to protons 1 and 2 in F127-COOH, which indicates the conversion of the terminal hydroxyl groups of the F127 chains into carboxyl groups by reaction with maleic anhydride.