Effect of copolymer structure on micellar behavior of acrylamide-octylphenylpoly (oxyethylene) acrylate surfactant

Acrylamide-octylphenylpoly (oxyethylene) acrylate copolymer (AM-C8PhEOnAc) surfactant is the copolymer of acrylamide (AM) and octylphenylpoly (oxyethylene) acrylate macromonomer (C8PhEOnAc). The effect of the copolymer structure on the micellar behavior in aqueous solution was studied using dynamic light scattering. It has been found that the length of ethylene oxide (EO) in the branch and the content of C8PhEOnAc in the copolymer surfactant have great effects on the size and distribution of the micelles. For AM-C8PhEO7Ac copolymer, at the concentration of 5 x 10(-4) g/ml, the micellar size increases with the increase of C8PhEO7Ac content. However, for AM-C8PhEO10Ac copolymer, the result is the opposite; the micellar size decreases with the increase of C8PhEO10Ac content. Larger C8PhEOnAc content leads to narrower micellar distribution. For copolymer surfactants with equal C8PhEOnAc content, when the concentration of copolymer solution is the same, the copolymer with longer EO length forms smaller micelles.