COMPARISON BETWEEN MONOMERIC AND POLYMERIC SURFACTANTS .2. PROPERTIES OF POLYSURFACTANTS IN AQUEOUS AND NONAQUEOUS SOLUTION

Solution properties of nonionic polymeric surfactants in methanol and water were investigated by static and dynamic light scattering and viscometry. Common polymer behavior was observed in dilute and semidilute methanol solution. In water, a strong influence of the degree of polymerization on the solution properties was found. The high molar mass sample formed aggregates of doubled molecular weight at a low concentration. These aggregates were stable against changes of concentration and behaved like flexible chains. No influence of temperature on the solution structure was observed, even close to the lower consolute boundary. The sample of lower molar mass obeyed behavior of a polymer in a poor solvent, and strong temperature effects were found. With increasing temperature the coil contracted. In semidilute solution an excess low-angle scattering and a slow mode were detected, which revealed uncommon temperature dependence. With increasing temperature the mass fraction of the large particles decreased but the diffusive motion became slower. This effect can be caused by a strong hydrodynamic coupling due to hydrophobic interaction. The influence of the chain length on the solution properties reveals the influence of topological constraints on the thermodynamic interactions in polymeric amphiphilic systems.