Directed self-assembly in “breath figure” templating of block copolymers followed by soft hydrolysis-condensation: One step towards synthetic bio-inspired silica diatoms exoskeleton

Abstract : Structural and chemical bio-inspired silica honeycomb films were obtained by combination of the directed self-assembly in “breath figure” templating to create honeycomb film and the post hydrolysis-condensation of a block copolymer PolyStyrene-block-Poly (3-(Trialkyloxysilyl)propyl methacrylate)) PS-b-PTEPM. Then pyrolysis at moderate temperature was used to achieve the elaboration of hierarchically porous silica film as bio-inspired diatoms frustules. In this work, block copolymers PS-b-PTEPM were synthesized by Nitroxide Mediated Polymerization to create honeycomb film by a “breath figure” bottom-up process. The PS block allows the formation of microporous film whereas the PTEPM block leads to the silica nanophase by in situ soft sol-gel reaction. The copolymer PS0.34-b-PTEPM0.66 allows the formation of a nicely patterned honeycomb film with nanocylinders of PS in a matrix of PTEPM. After soft hydrolysis-condensation and pyrolysis processes, a hierarchically-structured and fully inorganic honeycomb film is created as a synthetic bio-inspired silica diatom frustules.