Dye diffusion in polymer films subjected to supercritical CO2: Confocal raman microscopy and modelling

Abstract

Poly(ethylene terephthalate) films impregnated with Disperse Red 1 from a supercritical CO2 solution were studied using confocal Raman microscopy. Depth profiles of films dyed for different periods of time were measured using the oil immersion approach and concentration-depth plots of the relative dye concentration were generated. A one-dimensional Fickian diffusion model was used to evaluate the diffusion coefficient of the dye from the Raman microscopy data using a non-linear least squares regression. The calculated diffusion coefficient at 200 bar and 80°C was 6.75 ± 1.01 × 10-14m2 s-1. © 2005 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.