Kinetics of phase separation in polymer blends revealed by resonance light scattering spectroscopy

In this work, kinetics of phase separation in the blends of polystyrene (PS) and poly(vinyl methyl ether) (PVME) was investigated by a simple and sensitive method, i.e., resonance light scattering (RLS) spectroscopy. Owing to the aggregation of chromophores (phenyl rings) in the systems when phase separation occurred, RLS intensities were drastically enhanced and hence acted as a characteristic indicator. At the early stage of phase separation, two different RLS behaviors corresponding to spinodal decomposition (SD) and nucleation and growth (NG) were observed. The Cahn-Hilliard (C-H) linearization theory was found not applicable for kinetics analysis of the scattering data at lambda < 346 nm due to RLS effect near the absorption band. Based on a decomposition reaction model, the apparent activation energy of SD phase separation was estimated by the Arrhenius equation. In view of its simplicity and sensitivity of measurement, affordability and availability of instrument, and wide application range of polymer blends, RLS proved to be an effective means for characterization of microstructural variation in polymer blends.