Dynamical behaviour of polystyrene solutions under and close to theta conditions

Abstract

The dynamical behaviour of highly dilute solutions of polystyrenes dissolved in di-iso-octylphthalate has been studied using dynamic light scattering. The behaviour is in broad agreement with other studies of polystyrenes dissolved in theta solutions. Semidilute and concentrated solutions were also studied by the same technique, and the concentration and temperature crossovers from non-theta to theta behaviour were compared with the predictions of the temperature blob model. The solutions were also studied using Brillouin scattering; these observations confirmed that structural relaxation at gHz frequencies did not occur. These observations also indicated that the bulk modulus of the solutions was essentially that of the solvent until the polystyrene concentration was sufficiently high for the polymer to form a network.