Synthesis and characterization of polystyrene networks containing unattached photochromic polystyrene: preliminary results of self-diffusion measurements

Using the forced Rayleigh light scattering technique, the self-diffusion coefficient, D s, of polystyrene chains included in tridimensional structures was measured as a function of the molecular characteristics of the host polystyrene network, swollen at equilibrium. Photochromic linear polystyrenes were prepared anionically by deactivation of the living polymer with a spiropyran molecule. Polystyrene networks were obtained by copolymerization of living polystyrene with divinylbenzene. From swelling experiments, it was concluded that the addition of 8% labelled polystyrene to the network does not modify the elastic properties of the gel. We present preliminary results which demonstrate the feasibility of self-diffusion measurements on such systems, and reveal two different diffusion processes: a fast one that we attribute to chains free to move inside the network defects; and a slow one, corresponding to chains effectively entangled in the gel.