PHASE-SEPARATION DYNAMICS IN OFF-CRITICAL POLYMER BLENDS

A numeric integration of the spinodal decomposition process in an off-critical mixture of binary polymer blends is carried out to late times. The thermal fluctuation term in the evolution equation is found to be essential to avoid ''freezing'' of domain growth for such systems, an effect not present in small molecule systems. For deep quenches, late time domain growth follows the Lifshitz-Slyozov law and the scaling hypothesis is found to hold, although the scale invariant function differs in shape from the one obtained for a critical quench to the same temperature. For shallow quenches, although no freezing is observed, domain growth is found to be progressively slower as the spinodal curve is approached. For the model considered here, we do not find any evidence of the sharp transition in behavior that would be associated with a ''transnodal''.