Carbon dioxide - dilated block copolymer templates for nanostructured materials

摘要

Periodic polymer/metal (Pt or Ag) and polymer/semiconductor (PbS) nanocomposites are prepared using block copolymers dilated with carbon dioxide into supercritical CO_2 and infused into polystyrene-block-poly(acrylic acid) or polystyrene-block-poly(vinylpyridine) copolymers. Upon infusion, the acid or pyridine block selectively binds the metal precursor. The excess is removed from the polystyrene phase by subsequent CO_2 extraction. Reduction of the bound organometallic with hydrogen or hydrogen sulfide yields the desired metal or semiconductor clusters, which are confined to the precursor-binding domain and remain positioned on the copolymer lattice. The composites are characterized by transmission electron microscopy, x-ray scattering and electron diffraction.