Spinodal Decomposition in Isotopic Polymer Mixtures

Isotopic polymer mixtures are generally characterized by an upper critical solution temperature. In the present study we took advantage of this non-ideal mixing behavior and investigated the dynamics of spinodal decomposition for binary liquid mixtures of perdeuterated and protonated 1,4 - polybutadiene at the critical composition with light scattering. Owing to the minuteness of the refractive index difference (DELTA~0.003) the phase separation process can be followed between 0degrees and 180degrees in scattering angle, using macroscopic (~0.7 cm diameter) cylindrical specimens.