Dynamic acid static correlations in solutions of polymers in liquid and supercritical solvents: dynamic light scattering and small angle neutron scattering

Using dynamic light scattering and small angle neutron scattering technique s we investigate: the interrelation between the dynamic and static correlat ion lengths in liquid and supercritical polymer solutions in the poor solve nt domain Theta greater than or equal to T greater than or equal to T-c; wh ere Theta is the theta temperature and T-c is the critical temperature of p hase demixing, We observe the crossover between the hydrodynamic (T similar to Theta) and critical non-diffusive (T similar to T-c) regimes and demons trate that the dynamic correlation length xi(d)* for polymers in liquid and supercritical polymer solvents is described by the universal function xi(d )*/xi(d)*(Theta) = F* (tau') in terms of the de Genne's scaling temperature variable tau' = (T- T-c)/(Theta - T-c). (C) 2000 Elsevier Science B.V. All tights reserved.