Liquid−Liquid Limited-Supply Diffusion Studies in the Polystyrene−Poly(vinyl methyl ether) Pair

Abstract

Liquid−liquid diffusion at the interphase between poly(vinyl−methyl ether) (PVME) and polystyrene (PS) was experimentally studied using confocal Raman microspectroscopy. A combination of a specially designed experimental setup and a direct and precise quantification for the corrections to be applied to the Raman measurements allowed us to measure directly the PVME concentration along the diffusion path for a wide range of diffusion times. An already proposed and tested liquid−liquid diffusion model (based on liquid dynamics controlled by monomeric friction coefficients) was used to correlate and predict the detailed shape of the PVME concentration profiles and the diffusion rates as functions of diffusion time and temperature. The results obtained allowed us to discern among several approaches previously proposed in the literature to calculate monomeric friction coefficients in this system. Only the approach that considers independent monomeric friction coefficient values for PS and PVME (obtained from tr...