Nanostructured Metals from Soft Designer Macromolecules
By Ulrich Wiesner
MS&E Department, Cornell University
While in the Wiesner group considerable progress has been made
in the last 10 years on the preparation of mesoporous solids from
block copolymer self-assembly,1-6 the synthesis of ordered
mesoporous metal composites and ordered mesoporous metals is a
significant challenge because metals have high surface energies
that favor low surface areas. In this contribution results are
presented from the self-assembly of block copolymers with
ligand-stabilized platinum nanoparticles, leading to lamellar
(CCM-Pt-4) and inverse hexagonal (CCM-Pt-6) hybrid mesostructures
with high nanoparticle loadings.7 Pyrolysis of the CCM-Pt-6
hybrids produces ordered mesoporous platinum-carbon
nanocomposites with open and large (³10 nanometer) pores.
Removal of the carbon leads to ordered porous platinum
mesostructures. The platinum-carbon nanocomposites have very high
electrical conductivity (400 Siemens per centimeter) for an
ordered mesoporous material fabricated from block copolymer
self-assembly.
References
B.-K. Cho, A. Jain, S. M. Gruner, U. Wiesner, Mesophase
Structure-Mechanical and Ionic Transport Correlations in Extended
Amphiphilic Dendrons, Science 305 (2004), 1598-1601.
S. C. Warren, F. J. DiSalvo, U. Wiesner, Nanoparticle-tuned
assembly and disassembly of mesostructured silica, Nature Mater.
6 (2007), 156-161.
M. Templin, A. Franck, A. Du Chesne, H. Leist, Y. Zhang, R.
Ulrich, V. Schädler, U. Wiesner, Organically Modified
Aluminosilicate Mesostructures from Block Copolymer Phases,
Science 278 (1997), 1795-1798.
A. Jain, G. E. S. Toombes, L. M. Hall, S. Mahajan, C. B. W.
Garcia, W. Probst, S. M. Gruner, U. Wiesner, Direct Access to
Bicontinuous skeletal Inorganic Plumber's Nightmare networks from
block copolymers, Angew. Chem. Int. Ed. 44 (2005),
1226-1229.
J. Lee, M. C. Orilall, S. C. Warren, M. Kamperman, F. J.
DiSalvo, U. Wiesner, Direct Access to Thermally Stable and Highly
Crystalline Mesoporous Transition Metal Oxides with Uniform
Pores, Nature Mater. 7 (2008), 222-228.
M. Kamperman, C. B. W. Garcia, P. Du, H. Ow, U. Wiesner,
Ordered Mesoporous Ceramics Stable up to 1500°C from Diblock
Copolymers, J. Am. Chem. Soc. 126 (2004), 14708-14709.
S. C. Warren, L. C. Messina, L. S. Slaughter, M. Kamperman,
Q. Zhou, S. M. Gruner, F. J. DiSalvo, U. Wiesner, Ordered
mesoporous materials from metal nanoparticle-block copolymer
self-assembly, Science 320 (2008), 1748-1752.
