Controlled Self-Assembly of Polystyrene-<i>block</i>-Polydimethylsiloxane for Fabrication of Nanonetwork Silica Monoliths

Abstract

Herein, this work aims to carry out controlled self-assembly of single-composition block copolymer for the fabrication of various nanonetwork silica monoliths. With the use of lamellae-forming polystyrene-<i>block</i>-polydimethylsiloxane (PS-<i>b</i>-PDMS), nanonetwork-structured films could be fabricated by solvent annealing using a PS-selective solvent (chloroform). By simply tuning the flow rate of nitrogen purge to the PS-selective solvent for the controlled self-assembly of the PS-<i>b</i>-PDMS, gyroid- and diamond-structured monoliths can be formed due to the difference in the effective volume of PS in the PS-<i>b</i>-PDMS during solvent annealing. As a result, well-ordered nanonetwork SiO₂ (silica) monoliths can be fabricated by templated sol-gel reaction using hydrofluoric acid etched PS-<i>b</i>-PDMS film as a template followed by the removal of the PS. This bottom-up approach for the fabrication of nanonetwork materials through templated synthesis is appealing to create nanonetwork materials for various applications.