DYNAMIC LIGHT-SCATTERING FROM POLYSTYRENE-POLY(METHYLMETHACRYLATE) DIBLOCK COPOLYMER IN TOLUENE

The dynamical behavior of the diblock copolymer polystyrene-poly(methylmethacrylate) (PSPMMA) in toluene has been investigated by quasielastic light scattering. Two distinct modes have been observed in the autocorrelation function of the scattered light. In the semidilute range, at one polymer concentration c > c* (where c* is the overlap concentration) and far from the microphase separation, the variation of the two relaxation processes characterized by their frequencies GAMMA,GAMMA' and their amplitudes A,A' has been examined as a function of the scattering vector (q). The experimental results are in good agreement with the theoretical predictions.