Preparation of ordered nanocomposites in polymeric templates swollen by supercritical carbon dioxide.

摘要

Nanocomposites are of interest for numerous applications such as catalysis, photonic band gap materials, and waveguides. Ionomers and diblock copolymers have previously been used as templates for ordered nanocomposites. However, these processes have been limited to reactions within thin films or coprecipitation methods from solution due to mass transport limitations of ceramic and metallic precursors within the solid templates. This issue has been addressed by fabricating ordered nanocomposites using phase selective deposition of precursors into supercritical carbon dioxide (SC-CO₂) swollen polymeric templates. SCCO₂ is an effective plasticizing agent for most polymers and enhances mass transport of the precursors into polymeric templates while preserving the initial template morphology. By proper choice of template material, the precursor can be selectively bound within one phase of the template and reacted to produce the desired material. The resulting composite contains nanoparticles arranged in an ordered morphology dictated by the template over bulk dimensions. Polymer/ceramic and polymer/metal nanocomposites have been successfully synthesized using this technique.