Synthesis of Latex Particles with a Complex Structure As an Emulsifier of Pickering High Internal Phase Emulsions

A one-pot surfactant-free emulsion polymerization was described to produce uniform copolymer particles with core shell structure, single-cavity structure, single-cavity with multiprotrusions in edge structure, or multiprotrusions structure. The structure of the copolymer particles was tailored by simply varying the cross-linker divinylbenzene (DVB) concentration in the emulsion. The formation of the nonspherical shape of the polymer particles was attributed to the presence of local cross-linking domains in the latex particles at low conversion and the phase separation between the hydrophilic polymer rich region and hydrophobic polymer rich region in further polymerization. With the copolymer particles as an emulsifier, Pickering high internal phase emulsions (HIPEs) having an internal phase fraction of 85 vol% were obtained. The use of nonspherical particles not only stabilizes the Pickering emulsions against coalescence but also enhances the roughness of the void wall in the emulsion-templated porous polymers and even endows the porous polymers with high adhesive superhydrophobicity. This provides a simple and new approach to the fabrication of superhydrophobic surfaces.