Temperature and pH Responsive Janus Silica Nanoplates Prepared by the Sol–Gel Process and Postmodification

During the process of emulsifying and hydrolyzing, reactive poly(3-(triethoxysilyl)propyl methacrylate)-b-polystyrene (PTEPM-b-PS) diblock copolymers can self-assemble and become cross-linked to form hollow spheres in situ with polystyrene on their inner surfaces. The addition of tetraethoxysilane (TEOS), which was hydrolyzed and condensed together with PTEPM block, can make those spheres as soft foldable capsules or hard hollow spheres depending on the amount of added TESO. Then postmodification, the surface-initiated Atom Transfer Radical Polymerization (ATRP) was applied to afford stimuli-responsive spheres, and the corresponding responsive Janus nanoplates (RJPs) were finally obtained by crushing those responsive hollow spheres (HSs) showing smart tunable emulsifiability and great potential in oily water purification. This facile method to fabricate HSs and RJPs could be used for preparing different Janus polymer-inorganic capsules and nanoplates with varied functions by changing the chemical composition of copolymer surfactants as well as the postmodification process.