Microporous honeycomb-structured films of semiconducting block copolymers and their use as patterned templates

By Bert de Stalmach, Ulf Nijland, Harry Hadziioannou, Bert de Boer, U. Stalmach, H. Nijland. 2000

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Block copolymers are known to microphase-separate giving rise to ordered structures with nanometer scale periodicity. Moreover, it was observed recently that rod±coil block copolymers and amphiphiles, when thin films are cast from appropriate solvents on solid substrates, spontaneously form highly ordered, micro-porous honeycomb structures with a characteristic length scale. These films, with pore sizes in the order of micrometers, find applications in photonic and opto-electronic devices, catalysis, thermal insulation materials, and membranes. Usually, for the preparation of micro-porous materials, colloidal particles are used as templates, which have to be removed afterwards by solvent extraction or other tedious techniques. We synthesized a series of rod±coil block copolymers by alivingo free radical polymerization method using a derivative of 2,2,6,6-tetramethylpiperidinyl-N-oxyl (TEMPO). We modified a mono-aldehyde-functionalized poly(2,5-dioctyloxy-pphenylene vinylene) (rigid rod), prepared by a Siegrist polycondensation, to its nitroxide-functionalized analogue, which was used subsequently as a macro-initiator in the (co)polymerization of styrene and styrene derivatives (coil block) (Scheme 1). Drop casting of solutions of these novel block copolymers from CS2 and 1,2-dichloroethane resulted in the formation of honeycomb structures.

Subfields: Materials Chemistry

View Paper: https://www.semanticscholar.org/paper/265fb321455be7edd7060bf2ff9a8cb30597ffab