Fabrication of well-ordered mesoporous polyimide films by a soft-template method

A well-ordered mesoporous polyimide film was fabricated by a soft-template method using a microphase-separated structure of an amphiphilic block copolymer (BCP) as a template. Poly(amic acid)s (PAAs) as polyimide precursors and resol as a cross-linker for the stabilization of the nanostructure were found to be selectively miscible with the hydrophilic domain of the template BCP. Their mixture co-assembled and formed the desired ordered nanostructures. The composite films tended to form well-ordered nanostructures when PAAs with a flexible domain such as ether or methylene were used. Mesoporous polyimide films were obtained on thermal treatment of the composite films formed via the sequential processes of cross-linking of the resol, imidization of the PAAs, and selective decomposition of the template BCPs. A polyimide film with well-ordered hexagonal-packed cylindrical mesopores was successfully fabricated after the thermal treatment of the composite film based on PAA/polystyrene-block-poly(methacrylic aci...