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

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.