| Abstract: | A new application of infrared ellipsometry is reported. Specifically, the interdiffusion between thin films of miscible polymers—poly(methyl methacrylate) and poly(vinylidene fluoride)—is detected in a non‐invasive measurement. A novel technique of data analysis for interdiffusion was developed and is described. The validity of the approach is supported by simulations of diffusion in a bilayer. The onset of extensive interdiffusion over a time period of 15 min occurs at a temperature of 160 °C. At a temperature of 190 °C, the data show that complete mixing of a bilayer (850 nm thick) occurs within 30 s, which is consistent with previously reported values of the mutual diffusion coefficient. Infrared ellipsometry is non‐invasive, applicable at elevated temperatures and relatively fast and sensitive. Although, in these measurements, it was unable to determine a concentration profile at the interface, infrared ellipsometry was used successfully to detect when interdiffusion had occurred. Hence, it is a useful means for screening polymer pairs for miscibility. Copyright © 2004 John Wiley & Sons, Ltd. |
