THE EFFECT OF CHARGE AND LENGTH OF A BLOC KING POLYCATION ON PHASE-SEPARATION IN AQUEOUS SALT-CONTAINING SOLUTIONS OF NONSTOICHIOMETRIC POLYELECTROLYTE COMPLEXES

The behavior of water-soluble nonstoichiometric polyelectrolyte comple xes containing lyophilizing polymethacrylate anions and blocking poly( N-ethyl-4-vinylpyridinium) cations in sodium chloride solutions was st udied by the methods of turbidimetry, velocity sedimentation, and fluo rescence quenching. As the degree of polymerization of the polycation is decreased, the compaction of complex particles and phase separation are prevented, whereas decreasing the charge of the polycation leads to the collapse of complex particles and assists in phase separation. According to proposed mechanism for the phase transition, the driving force of this transition is provided by the collapse of particles of t he nonstoichiometric polyelectrolyte complex, which leads to an increa se in the local concentration of free carboxyl groups of polyanions an d their low-molecular-mass counterions.