Abstract The influences of cations

anions

anionic surfactant and non-ionic surfactant on the molecular coil dimension of hydrolyzed polyacrylamide (HPAM) were studied by using dynamic light scattering (DLS)

and ther mechanism was analyzed by applying the Stern-Graham double electrode layer model theory

paternoster model theory and dynamic model.The results show that the influence of anions on the HPAM molecular dimension (Dh) is little

but comparing against anions

the influence from cations is much greater

and the decreasing degree of Dh with the cation concentration increasing decreases gradually.The order of action capacity of Ca2+

Mg2+

K+ and Na+ for Dh is Mg2+＞Ca2+＞Na+＞K+.When the anionic surfactant is introduced into polymer solutions

Dh decreases with the concentration of anionic surfactant increasing first

then increases and decreases again.Moreover

because of the powerful electrostatic repulsion

the capacity of anionic surfactant molecules to adsorb on the surface of polymer molecules is weak

and it is difficult to form the “anionic surfactant_polymer” complex.However

the nonionic surfactant can adsorb on the polymer molecular chains in the form of micellar aggregate

forming “nonionic surfactant-polymer” complex

and result in the Dh increasing with the nonionic surfactant concentration increasing.