DETERMINATION OF INTERDIFFUSION IN THIN POLYMER-FILMS USING FTIR REFLECTION-ABSORPTION SPECTROSCOPY

FTIR reflection absorption spectroscopy (RAS) has been used to develop a method to study interactions in artificial interphases of polymer b lends. Two films of Poly(vinyl ethyl ether) (PVEE) and poly(ethylene-c o-acrylic acid) (EAA), with thicknesses ranging from 100 to 600 angstr om each, were solution cast on a gold surface and annealed at 125-degr ees-C for different times. The carboxylic acid groups of EAA different ly hydrogen bonded to different species, and the diffusion of EAA and PVEE into each other could be followed by studying the C=O bands in th e infrared spectra. One advantage of studying these thin films instead of entire blends is that the influence of the bulk properties is redu ced, and we therefore observe the behavior of the molecules in the art ificial interphase itself. Quantitative measurements of the amount of hydrogen bonds made it possible to calculate the diffusion constant an d also to obtain a measure of the interphase thickness after different annealing times.