Self-Assembly Behavior of Hydrophobically Associating Polyacrylamide in Salt Solution

The self-assembly behavior of hydrophobically associating polyacrylamide(HAPAM)in salt solution was studied by static light scattering,dynamic light scattering,and atomic force microscopy(AFM). The apparent weight average molecular weight(Mw,a ),root mean square radius of gyration(Rg), hydrodynamic radius(Rh),and the second virial coefficient(A2),were investigated.The ratio ofRg toR h was used to determine the molecular shape of the polymer in salt solution.As the salt concentration increased,the polymer chain transformed from stretch to curl.