ORDERING PHENOMENA OF POLYMERIC CLUSTERS NEAR THE SOL-GEL TRANSITION - LIGHT-SCATTERING EXPERIMENTS

Light scattering has been performed on solutions of polymeric clusters of poly(vinyl chloride) near the sol-gel transition where a peak in t he scattering function is observed. This effect is analysed here in te rms of a liquidlike order of polydisperse clusters. Clusters distribut ions were quenched to T = 20-degrees-C for solutions prepared at high temperature at different concentrations PHI(Q) below the critical gela tion concentration PHI(Q). For a system diluted after quenching, the weight average molecular weight M(w)(PHI(Q)) and the peak position q are shown to scale as M(w) is-proportional-to R(z)1.6 +/- 0.1 and q i s-proportional-to PHI-1/3 M(w)1/3, respectively in which R(z)(PHI(Q)) is the z-average radius of gyration and PHI(PHI(Q)) is the polymer vol ume fraction.