Diffusion of Water and Diatomic Oxygen in Poly(3-hexylthiophene) Melt: A Molecular Dynamics Simulation Study

Diffusion behavior of water, diatomic oxygen, and a mixture of both into a poly(3-hexylthiophene)[P3HT] melt were investigated using Molecular Dynamics Simulation. Once simulations were complete, the data was analyzed to determine the diffusion coefficient of those molecules in P3HT using Fick’s law. The diffusion coefficient values were then plotted as a function of concentration and temperature to determine if trends existed. For both water and oxygen, no dependence was observed of the diffusion coefficient on concentration and temperature for the ranges studied. However, a variation in the diffusion coefficient on concentration was observed due to the expected inhomogeneity of the P3HT melt. In the presence of O2, the diffusion of H2O decreased significantly by a factor between four and five, while in the presence of H2O, the diffusion of O2 slightly decreased.