Nanocasting nanoporous inorganic and organic materials from polymeric bicontinuous microemulsion templates

Abstract

Ternary blends of two homopolymers and a diblock copolymer can self-assemble into interpenetrating, three-dimensionally continuous networks with a characteristic length scale of similar to 100 nm. In this review, we summarize our recent work demonstrating that these equilibrium fluid phases, known as polymeric bicontinuous microemulsions (B mu E), can be designed as versatile precursors to nanoporous materials having pores with uniform sizes of similar to 100 nm. As a model system, nanoporous polyethylene (PE) is derived from B mu Es composed entirely of polyolefins. This monolithic material is then used as a template in the synthesis of other nanoporous materials for which structural control at the nm scale has traditionally been difficult to achieve. These materials, which include a high-temperature ceramic, polymeric thermosets and a conducting polymer, are produced by a simple nanocasting process, providing an inverse replica of the PE template. The PE is further used as a template for the production of hierarchically structured inorganic and polymeric materials by infiltration of mesostructured compounds into its pore network. The work described herein represents an unprecedented suite of nanoporous materials with well-defined pore structures prepared from a single PE template. They are anticipated to have potential application in diverse technological areas, including catalysis, separations and electronic devices. Polymer Journal (2012) 44, 131-146; doi:10.1038/pj.2011.136