Abstract: An amphiphilic graft copolymer PAA-g-C8PhEO10Ac with poly(acrylic acid) as a main chain and octylphenyl polyoxylethylene ether(C8PhEO10) as graft chains was synthesized via free radical copolymerization of acrylic acid (AA) and amphiphilic C8PhEO10Ac maromonomers. The number average molecular weight of the copolymer was determined to be 4.37×10⁴ by gel permeation chromatography(GPC). The structure and composition of the copolymer obtained were characterized by FTIR and 1H-NMR. The molar ratio of acrylic acid monomer to macromonomer is 9:1 in the copolymer and 32 C8PhEO10 branch chains attach to a poly(acrylic acid) backbone. Self-assembly behavior of PAA-g-C8PhEO10Ac in aqueous solution was preliminary studied by means of surface tension measurements, fluorescent probe and TEM. It was found that spherical micelles are formed in water phase at cmc1 and cmc2. As compared with those at cmc1, the surface tension of the copolymer solution and the polarity in the micellar core further decrease at cmc2. Furthermore the diameter of the micelles increases and the micelles become compact. The presence of 1.0%(w) sodium chloride results in the lower surface tension of the copolymer solution and the weaker polarity in micellar core.

Key words: Amphiphilic graft copolymer, Acrylic acid, n-octylphenyl polyoxyethylene ether, Macromonomer, Polymeric surfactant