Formation and properties of core–shell pentablock copolymer/silica hybrids

Abstract

Two novel core–shell pentablock copolymer/silica hybrids are prepared for coating applications via growing silica on the precursor of pentablock copolymer PDMS-b-(PMMA-b-PMPS)2 (PDMM), which is synthesized by dimethylsiloxane (DMS), methylmethacrylate (MMA) and 3-(trimethyoxysilyl)propyl methacrylate (MPS). The hybrid of PDMM core/silica shell (PDMM@SiO2) is obtained by the assembled PDMM in THF/CH3OH solution with tetraethyl orthosilicate (TEOS), but the hybrid of silica core/PDMM shell (SiO2@PDMM) is obtained by the hydrolyzed TEOS with –Si(OCH3)3 groups during assembling of PDMM in THF solution. PDMM@SiO2 could produce a film distributed agminated SiO2 particles with 45 nm roughness, but SiO2@PDMM could produce a film scatted individual SiO2 particles with 26 nm roughness. Therefore, PDMM@SiO2 film gives an obvious hydrophobicity (116°), higher Tg (121 °C), high Td (>400 °C), low amount of water absorption (300 Hz of Δf), low viscoelasticity (−0.32 of ΔD/Δf), but tight layer structure (10 × 10−6 of ΔD) and high storage modulus (2350 MPa). However, both core–shell hybrids have the similar adhesion to the substrate (185–187 N).