DEPOLARIZED LIGHT-SCATTERING FROM SEMIDILUTE POLYSTYRENE CARBON-TETRACHLORIDE SOLUTIONS

Polarized and depolarized light scattering measurements are reported for polystyrene-carbon tetrachloride solutions in the vicinity of the coil overlap concentration. The molecular weight of the polystyrene used in this experiment was M(w) = 2 x 10(7). The radius of gyration, determined in dilute solution conditions, was R(G) = 196 nm. At volume fraction phi = 0.014, polarized light scattering yields a correlation length xi = 14.1 nm. The depolarized light scattering intensity is practically independent of concentration. The characteristic lengths describing the depolarized spectra are much larger than those for the polarized scattering, and are of the order of 100 nm. These lengths are consistent with estimates of the distance between entanglements in the solutions.