Complexation Between Partially Hydrolyzed Polyacrylamide (HPAM) and Quaternized Poly(4‐Vinylpyridine) (QP4VP)

The evolution of conductivity and potentiometric measurements during complexation process in a system of short chain of quaternized poly(4‐vinylpyridine) (QP4VP) and long chain of partially hydrolyzed polyacrylamide (HPAM) suggest two stages, the first is the formation of initial complex through counter‐ion exchange reaction, the release of counter‐ions have been thought to be ended at the first stage. However, it could extend to the second if the ions trapped in uncharged area inside the complex and if it along with the creation of new opposite charged functions. The second stage is reflected in the reorganization of the initial complex toward an equilibrium state, occur via acid base reaction that lead to hydrogen transfer and the creation of balance state between electrostatic interaction and hydrogen bond in polyelectrolyte exchange reactions between polyions chains within the complex, or with free polymer chains in solution. The first stage is fast comparing with the second; nevertheless, it is slow compared with many other systems of polyelectrolyte complex (PEC) that proceed within milliseconds, this difference is probably caused by the intramolecular and intermolecular association in HPAM that hardens and slows the penetration and the access of QP4VP chains to form the complex. Kinetic studies shows strong dependencies on neutralization degrees of QP4VP in both stages affect the evolution of complexation and the final structure of the PEC formed. The proposed mechanisms of the process may explain all the dependencies found.