Synergetic regulation of CO2 and light for controllable inversion of Pickering emulsions

Abstract

Manipulating inversion of Pickering emulsions via “green” and “erasable” external stimuli is at the forefront of developing emulsion-templated materials on account of no chemical addition and convenience. Herein, a type of synergetic CO₂- and light-triggered Pickering emulsion was constructed using a special emulsifier formulated by poly[2-(diethylamino)ethyl methacrylate] (PDEAEMA)-grafted-polydopamine (PDA) nanoparticles. Taking advantage of the remarkable photothermal-conversion ability of PDA and tunable amphiphilicity of PDEAEMA, water-in-oil (W/O) emulsions stabilized by PDA–PDEAEMA particles could be converted into oil-in-water (O/W) types upon CO₂ treatment, and then switched between the W/O type and O/W type reversibly by turning light irradiation on and off. Such controllable emulsion inversion through synergetic CO₂ and light stimuli could be applied in temperature-dependent heterogeneous catalysis and separation.