Ionic conductivity in a chitosan membrane for a PEM fuel cell using molecular dynamics simulation

A classical molecular dynamics simulation using a COMPASS force field was applied to systems contained chitosan, hydronium ions, various amounts of water: 10, 20, 30 or 40% water. The simulation predicted the diffusion coefficient, the ion conductivity, the coordination between particles. The system containing 40% water is most suitable as a conducting material because it has the highest ion conductivity value (7.14 × 10−2 S/cm). Such a material was studied in a temperature range of 298–360 K, the conductivity results followed Arrhenius behavior. A study at 70, 80, 90° of deacetylation (DDA) at a constant of 40% water content showed the same trend in conductivity behavior. The coordination was considered in evaluating the location of particles in order to understand the transport mechanism of the ions. Conductivity is appropriate in the systems in which the Eigen ion, water cluster are formed.