Polymer flooding agents play an important role in enhanced oil recovery (EOR)．A New way to prepare polymer flooding agents through complexation of two oppositely charged polymers has attracted much attention．Poly(acrylamide-co-dimethyldiallylammonium chloride)[P(AM-DMDAAC)] is a novel cationic polyeletrolyle which can be used as the component of polyelectrolyte complex for EOR．The basic parameters and behavior of P(AM-DMDAAC)

in which cationic component is controlled

in 0.1 mol／L NaCl aqueous solution were characterized by dynamic and static laser light-scattering．The apparent basic parameters of P(AM-DMDAAC) are as follows：=5.04×l05 g·mol-1

〈Rg〉app=39.9 nm

A2

app=1.57×10-4 cm3 mol·g-2．From the results of dynamic light scattering

the curves of Dt versus c and scattering angle θ

all are nonlinear and turning down．The phenomena imply that both the chains of P(AM-DMDAAC) in 0.1 mol／L NaCl aqueous solution appear polydispersity and there are some associates．Furthermore

the distribution ranges of the hydrodynamic radii (Rh) can be divided into two parts

for Rh value

one part is relative smaller

another is relative larger．Reasonably

the later can be attributed to association. When temperature raises

both parts develop towards the direction of the reducing Rh

so the behaviors of association and disassociation are evidenced again．Under certain conditions

the existing of“metastable behavior” is a power circumstantial evidence for association behavior of P(AM-DMDAAC) in 0.1 mol／L NaCl aqueous solution．These results provide basic data for preparing novel flooding agents by complexation of polyelectrolyle.