Selective sequential infiltration synthesis of ZnO in the liquid crystalline phase of silicon-containing rod-coil block copolymers.

The combination of block copolymer (BCP) thin film self-assembly and selective infiltration synthesis of inorganic materials into one BCP block provides access to various organic-inorganic hybrids. Here, we apply sequential infiltration synthesis, a vapor-phase hybridization technique, to selectively introduce ZnO into the organic microdomains of silicon-containing rod-coil diblock copolymers and a triblock terpolymer, polydimethylsiloxane (PDMS)--poly{2,5-bis[(4-methoxyphenyl)-oxycarbonyl]styrene} (PDMS--PMPCS) and PDMS--polystyrene--PMPCS (PDMS--PS--PMPCS), in which the PMPCS rod block is a liquid crystalline polymer. The in-plane cylindrical PDMS--PMPCS and core-shell cylindrical and hexagonally perforated lamellar PDMS--PS--PMPCS films were infiltrated with ZnO with high selectivity to the PMPCS. The etching contrast between PDMS, PS and the ZnO-infused PMPCS enables the fabrication of ZnO/SiO binary composites by plasma etching and reveals the core-shell morphology of the triblock terpolymer.