Inorganic Reinforced Poly(ionic liquid) Microcapsules: Confined Cooling-Assisted Phase Separation Self-Assembly and Enhanced Electroresponsive Properties

A simple preparation of inorganic reinforced poly(ionic liquid) (PIL) microcapsules by combining dispersion polymerization and confined cooling-assisted phase separation self-assembly is reported. Silane coupling agent-modified PIL microbeads are first prepared by dispersion polymerization. Then, the microbeads are dissolved in a theta solvent composed of good solvent and non-solvent to form hollow SiO_x microcapsules at a relatively high temperature. Finally, the solution is cooled to induce the nucleation and growth of dissolved PIL chains on the inner and outer surface of hollow SiO_x microcapsules to form inorganic reinforced microcapsules with asymmetric PIL/SiO_x/PIL sandwich-like shell. The morphology of microcapsules can be controlled by adjusting PIL concentration and cooling rate. The inorganic reinforced microcapsules show enhanced suspended stability and electroresponsive characteristic when used as the dispersed phase of smart suspensions.