Abstract: Polymeric surfactants were prepared by ultrasonic copolymerization of carboxy methyl cellulose (CMC) and alkyl poly(etheroxy) acrylate. The polymeric microemulsion was prepared by mixing polymeric surfactants aqueous solution, toluene and alcohol at given ratios. The results of dynamic laser scattering indicated that the microemulsion droplets have almost same size and conformation, and the size of polymeric microemulsion particles, which is much bigger than that of low molecular weight surfactants, is beyond the limit of microemulsion definition. But the systems are still thermodynamically stable. The results of isotope tracer analysis indicated that more and more alcohol molecules insert to the interface of oil and water, changes the interfacial structure of phases and finally help microemulsion formed. The whole structure of microemulsion is oil core surrounded by water. The formation of reverse micelles is shown to be unlikely even in toluene-rich region.

Key words: Polymeric surfactant, Carboxy methyl cellulose, Microemulsion