The fluorescence quenching techniques

including steady—state fluorescence quenching(SSFQ) and time—resolved fluorescence quenching(TRFQ)

were applied to determine the aggregation number(NA)of self-assembled aggregates of the hydrophobically associating water-soluble muhicopolymer of acrylamide(AM)and 2-phenoxylethyl acrylate(POEA)．This polymer easily hydrophobicany associates in water to form micelle—like aggregates

which serve as solubilization sites of pyrene probe molecules and quencher benzophone．Fluorescence results measured were well fit to the Possion quenching model It was found that the NA was influenced significantly by the hydrophobe content and the hydrophobic block size of the copolymer．The NA enhanced with increasing the hydrophobe content and decreasing the block length

as well as increased with increasing the concentration of copolymers and sodium chloride．The relationship among the polymer chain structure

aggregation number and viscosity of polymer solutions were discussed.