A water soluble comb-like polymer from the statistical copolymer of acrylic acid and octadecyl methacrylate has been accomplished through transesterification reaction with methoxy poly(ethylene glycol) of molecular weight 5000. The high non-polar characteristics of microdomains as suggested from an higher I-3/I-1, emission intensity ratio of pyrene, and a very high aggregation number of 821 +/- 4, demonstrate that PEO grafts play a significant role in promoting the hydrophobic association process in aqueous medium. A very low intrinsic viscosity (29 ml/g) and the linear variation of eta (sp)/c with c demonstrate formation of aggregated structures in compact coil conformation.