Application of fluorescence energy transfer in thin layered films to the study of polymer-polymer interdiffusion and small molecule self-diffusion

Knowledge of diffusion coefficients of small molecules in glassy polymer matrices, especially in the vicinity of the glass transition temperature, T_g, is important in many applications. We propose a method using energy transfer between small molecules as measured by fluorescence emission intensities to examine the diffusion of small molecules in glassy polymer matrices. This technique enables one to calculate diffusion coefficients without determining the actual spatial concentration distribution. Specifically, this method involves bringing together two monodisperse polymer films where one film is doped with a fluorescence donor, and the other, a fluorescence acceptor.