Competing growth kinetics in simultaneously crystallizing and phase-separating polymer blends

The kinetic interplay between crystal superstructure growth and late-stage liquid phase coarsening in a polymer blend has been examined. By controlling the relative quench depths for liquid-liquid phase separation and crystallization, the growth kinetics of the characteristic length scales of the simultaneous ordering processes show a crossover from crystallization dominated to phase-separation dominated behavior. Based on a scaling argument for late-stage coarsening during spinodal decomposition, we argue that this kinetic crossover is inevitable in a blend for which the critical temperature of liquid-liquid phase separation is well above the equilibrium melting temperature of the blend. (C) 2002 American Institute of Physics.