Fabrication of robust honeycomb polymer films: a facile photochemical cross-linking process.

Highly ordered honeycomb films are prepared by breath-figure method using an amphiphilic diblock copolymer of polystyrene-block-polyacrylic acid (PS-b-PAA). By simply cross-linking PS matrix via deep ultraviolet (UV) irradiation, both the solvent and thermal stability of the porous films was significantly improved while retaining the three-dimensional (3D) structures. The film surface wettability was changed from hydrophobicity to hydrophilicity by the formed polar groups during the photochemical process.