Ion diffusion in polyelectrolytes: A simple Monte-Carlo model

Monte Carlo simulations were completed for ion diffusion through polymer matrices. The parameters can be chosen so that any type of neat polymer electrolyte can be modeled. The present study focuses on polyelectrolytes. Restricting anion diffusion in such systems guarantees a cation transference number of one. The bound anions can create deep potential wells from which nearby cations cannot escape. The dynamic bond percolation model was expanded to include local harmonic motion of bound anions in polylectrolyte systems. The motion of these anions facilitates cation escape from potential wells, and thus aids in overall conductivity, while still retaining cation transference number of one. The simulations show a substantial dependence of diffusion on ion correlation. Increasing the thermal energy or the dielectric constant of the host reduces this dependence.