Nanoporous Materials Formed in Condensed Carbon Dioxide

ORAL

Abstract

We propose a strategy utilizing condensed carbon dioxide as a selective--solvent for creating nanoporous materials from block copolymer templates. Cylinder--forming polystyrene--$b$--polylactide ($f_{PLA}$ = 0.37) monoliths were annealed in carbon dioxide at constant temperature and various solvent densities. The swollen structures were then quenched at low temperature isochorically. Small-angle X-ray scattering measurements indicated the domain spacing increased with increasing CO$_{2}$ density. This result is consistent with the formation of cylindrical pores within the intact polylactide domains, a conclusion confirmed by scanning electron micrographs of the processed monoliths. This controlled, non-destructive technique allows for creating tunable pore structures from a single block copolymer.

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Authors

  • William Edmonds

    Department of Chemical Engineering and Materials Science, University of Minnesota

  • Timothy P. Lodge

    Department of Chemistry and Department of Chemical Engineering and Materials Science, University of Minnesota, University of Minnesota, Department of Chemical Engineering and Materials Science, University of Minnesota, Department of Chemistry and Department of Chemical Engineering and Materials Science, University of Minnesota, Minneapolis, MN

  • Marc Hillmyer

    Department of Chemistry, University of Minnesota, Dept. of Chemistry, U. of Minnesota, University of Minnesota