Mutual diffusion at polystyrene/poly(vinyl methyl ether) as measured by ATR‐FTIR and rheometry

Mutual diffusion at PS/PVME (polystyrene/polyvinyl methyl ether) interface both below and above the glass transition temperature, T_g, of polystyrene was probed by Attenuated total reflection (ATR) and rheometry techniques. The results were analyzed with a simple three layer model and a combination of Fickian and Case‐II diffusion models. The mutual diffusion coefficients obtained by the two techniques are compared and the importance of Case‐II diffusion is discussed.