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Mesostructured and Mesoporous Silicates

We employ amphiphilic diblock copolymers including poly(isoprene-block-ethylene oxide) (PI-b-PEO), an amphiphilic block copolymer to structure direct the assembly of aluminosilicate-type nanoparticles.

The nanoparticles are produced in a sol-gel process, where an organically modified silicon alkoxide and an aluminum alkoxide are mixed with water. Mixing the nanoparticles with the block copolymer, PI-b-PEO produces well-ordered mesostructures with domains consisting of PI (hydrophobic) and PEO+Aluminosilicate (hydrophilic).

By varying the amount of aluminosilicate-type nanoparticles in the hybrids, a wide range of morphologies can be produced which, in effect, map out the phase diagram of a typical block copolymer.

alsilicate schematic
TEMs of phases

The morphologies typically obtained are (from left to right) bcc spheres, hexagonally packed cylinders, inverse plumber's nightmare (cubic bicontinuous) lamellae, gyroid, inverse hexagonal cylinders and inverse bcc spheres. These are produced by adding increasing volume fractions of the aluminosilicate-type nanoparticles.

Nanomaterials
These aluminosilicate-PI-b-PEO hybrids can then either be dissolved to produce "hairy" nano-objects such as spheres, cylinders and lammellae, or heat-treated to burn out the organic material leaving behind mesostructured aluminosilicate ceramic materials.

All images and text Copyright 2008

Wiesner Research Group - Cornell University

Relevant References:

E. Verploegen, B. T. Dworken, M. Faught, M. Kamperman, Y. Zhang, U. Wiesner, "Tuning Mechanical Properties of Block Copolymer-Aluminosilicate Hybrid Materials", Macromol. Rap. Comm. 28, 2007, 572-578.

A. Jain, G. Toombes, L. Hall, S. Mahajan, C. Garcia, W. Probst, S. Gruner, U. Wiesner, "Direct Access to Bicontinuous skeletal Inorganic Plumber’s Nightmare networks from block copolymers", Angew. Chem. Int. Ed. 44, 2005, 1226-1229

Simon, R. Ulrich, H. Spiess, U. Wiesner, "Block Copolymer-Ceramic Hybrid Materials from Organically Modified Ceramic Precursors" Chemistry of Materials 13(10), 2001, 3464-3486.

A. Jain, U. Wiesner. "Silica-Type Mesostructures from Block Copolymer Phases: Formation Mechanism and Generalization to the Dense Nanoparticle Regime" Macromolecules, 37(15), 2004, 5665-5670.

M. Templin, A. Franck, A. Du Chesne,H. Leist, Y. Zhang, R. Ulrich, V. Schadler, U. Wiesner. "Organically modified aluminosilicate mesostructures from block copolymer phases". Science, 278(5344), 1997, 1795-1798.

R. Ulrich, A. Du Chesne, M. Templin, U. Wiesner, "Nano-objects with controlled shape, size, and composition from block copolymer mesophases" Advanced Materials, 11(2), 1999, 141-146.