Synthesis of ABA triblock copolymer nanoparticles by polymerization induced self-assembly and their application as an efficient emulsifier†
ABA triblock copolymer nanoparticles of poly(2-hydroxypropyl methacrylate)-block-polystyrene-block-poly(2-hydroxypropyl methacrylate) (PHPMA-b-PS-b-PHPMA) with a hydrophobic core of the polystyrene (PS) block and a hydrophilic corona of the poly(2-hydroxypropyl methacrylate) (PHPMA) block were synthesized by dispersion RAFT polymerization. It is found that the particle diameter of the PHPMA-b-PS-b-PHPMA nanoparticles increases with the chain extension of the PS block and decreases with the increasing degree of polymerization (DP) of the PHPMA block. In comparison with the poly(2-hydroxypropyl methacrylate)-block-polystyrene (PHPMA-b-PS) diblock copolymer nanoparticles with a similar chemical composition, the PHPMA-b-PS-b-PHPMA nanoparticles have a larger diameter, and the chain density of the PHPMA chains tethered to the PS core is higher. It is found that the PHPMA-b-PS-b-PHPMA nanoparticles can decrease the n-hexane/water interfacial tension more than the PHPMA-b-PS nanoparticles and may act as an efficient emulsifier.