DIFFUSION OF SPHERICAL MICRONETWORKS IN POLYMER DILUENT SYSTEMS AND MELTS STUDIED BY DYNAMIC LIGHT-SCATTERING TECHNIQUES

Spherical polystyrene (PS) micronetworks can be prepared in microemuls ion with bulk radii of 5 - 60 nm and different cross-linking densities . The diffusion of these PS spheres has been studied in polymer diluen t systems ranging from dilute solutions to plasticized melts by using forced Rayleigh scattering and photon correlation spectroscopy. On inc reasing the PS concentration, a colloid glass transition is observed a t a volume fraction PHI(C) almost-equal-to 0.64 of the swollen spheres . At higher concentration inside the ''colloid glass'' state the spher e diffusion is slowed down and becomes very complex but can be observe d up to the limit of a melt of collapsed spheres.