Synergistic Effect of Copolymer Particle and Surfactant on the Morphology of Macroporous Materials Based on High Internal Phase Emulsion

The open porous materials (PolyHIPEs) based on high internal phase emulsions (HIPEs) stabilized by copolymer particles had been prepared through adding small quantity (about 0.5 wt% relative to the external phase) of cationic surfactant, cetyltrimethylammonium bromide (CTAB), into the oil (external) phase. The effect of copolymer particle concentration, surfactant concentration and CTAB position in HIPEs on the morphologies of PolyHIPEs was investigated. All these factors could tune the internal structures of the Poly- HIPEs and some of them generated pore throats on the pore wall. Obvious synergistic interaction between the negative-charged particles and cationic surfactant CTAB in HIPE was displayed: CTAB could not only adsorb on the oil-water interface competitively with the copolymer particles but also cross the interface to absorb on the particle surface, which changed the particle hydrophilicity. The further investigation on the stability of HIPE proved that the HIPEs with CTAB in the oil phase were more prone to form open porous materials after polymerizing the monomer in the external phase.