Emulsification Properties of Complex Aqueous Solution by Mixing Two Kinds of Amphiphilic Polymers Selfassembly Micelles

A new amphiphilic random copolymer P(St-co-VM-co-AA), referred to PSVA， was synthesized using styrene (St), photosensitive monomer 7(4-vinylbenzyloxyl)4-methylcoumarin (VM) and acrylic acid (AA) through free radical copolymerization. Using St and methacrylic acid 2-(dimethylamino) ethyl ester (DMAEMA) as monomer, another amphiphilic random copolymer P(St-co-DM), referred to PSDM was synthesized. These copolymers were characterized by gel permeation chromatography (GPC) and proton nuclear magnetic resonance (1H-NMR). PSVA anionic micelles and PSDM cationic micelles were prepared with copolymer PSVA and PSDM via selfassembly method in selective solution (DMF-H2O)， respectively. Complex micelles were generated by mixing the anionic and cationic micelles together. DLS and Zeta potential investigations showed that the size and surface charge of the complex micelles varied with the mixing ratio of anionic and cationic micelles. Emulsions were prepared by equal volume toluene and water, using complex micelles of PSVAPSDM as Pickering emulsifier of varied mass ratios. Photographs of the vessels were taken with digital camera and droplet sizes were shown by light microscopy. Finally, a variety of complex micelles were prepared by controlling mass ratios of anionic micelle and cationic micelle. Compared to either single PSVA anionic micelle or PSDM cationic micelle，the emulsification effect of complex micelles PSVAPSDM were increased, especially when w(PSDM) was 33.3%. And when w(PSDM) was 24.2%, Zeta potential of complex micelles solution was zero. Furthermore, crosslinked PSVA anionic micelles (CL-PSVA) were obtained by photodimerization of the pendant coumarin groups in PSVA under UV irradiation. The emulsion produced by the complex micelles CL-PSVAPSDM as emulsifiers showed even better stability upon standing.