Fabrication of hierarchically ordered hybrid structures over multiple length scales via direct etching of self-organized polyhedral oligomeric silsesquioxane (POSS) functionalized block copolymer films

A novel fabrication of hierarchically ordered organic and inorganic hybrid structures at length scales ranging from nanometers to micrometers was demonstrated by oxygen plasma treatment of self-organized silicon-containing block copolymer films. The rod-coil type silicon-containing block copolymer, polystyrene-b-polyisoprene with polyhedral oligomeric silsesquioxane (POSS)-modified side chains, was successfully synthesized by hydrosilation of polystyrene-b-poly(1,2-ran-3,4-isoprene) block copolymer with hydrido-heptacyclopentyl substituted POSS. The films were prepared from the polymer solution by casting on silicon wafers under a moist air flow. The self-organized microstructures were investigated by electron microscopy. It was found that the hexagonally packed micropores and phase-separated nanodomains were formed within the films. Oxygen plasma etching of the films provided novel hierarchically ordered hybrid structures.