High field ion mobility in dielectric polymers: A molecular dynamics study of water in poly(dimethylsiloxane)

Detailed understanding of charge transport phenomena in dielectrics is important in order to understand the influence of chemical composition on the dielectric properties. Material simulation methods such as density functional theory (DFT) and molecular dynamics (MD) can be used to calculate basic properties of the material. Here we focus on mobility of ions at high fields by applying MD simulations. In a recent study of ionic mobility in polyethylene, it was shown that ion mobility starts to deviate from the Einstein relation at high fields, resulting in a linear increase of the mobility [1]. We argue that this is due to conformational change of the surrounding polymers through elastic scattering which facilitates and thus accelerates the charged molecule. Here we investigate this effect of water in poly(dimethylsiloxane) (PDMS).