Diffusion and Interaction in Gels and Solutions

Abstract: The self-diffusion in polymer gels and solutions has been studied experimentally and by Brownian dynamics simulations. A new theory is presented concerning systems with purely repulsive interactions between the diffusants and the polymers. Theoretical predictions of the influence of diffusant size, polymer concentration, polymer radius, and the polymer persistence length show good agreement with simulations and experimental data. For systems where additional attractive interactions are present, simulations and experiments show important characteristics of the interplay between repulsive and attractive interactions on the diffusion.