Abstract: Contrasted with polyacrylamide (PAM), the self-assembly behavior andmicrostructure ofhydrophoblically associating polyacrylmide (HAPAM) in aqueous solution have been studied by means of fluorescence spectrum and dynamic light scattering methods. The experimental results show thatHAPAM can easily self-assemble to form a stock aggregate by hydrophobic driving
force in aqueous dilute solution. The critical associating concentration (CAC) ofHAPAM is very low. The dynamic variation of the apparentparticle diameterofHAPAM and PAM are observed by dynamic light scattering. At the CAC ofHAPAM, the particle ofHAPAM from small size grows into large size, but PAM does not show this phenomenon at the same polymer concentration. This shows that self-assembly in aqueous solution is the unique behavior ofHAPAM.

Key words: wordshydrophobically associating polyacrylamide, self-assembly, fluorescence spectrum, dynamic light scat