Dielectric properties of organosilicons from first principles

Density functional perturbation theory calculations have been performed to determine the dielectric constant of Si “doped” polyethylene (PE). Substitution of C atoms in PE by Si ranging from 0 to 100% has been considered. Both the electronic and ionic contributions to the dielectric constant increase with increasing Si content. These increases are attributed, respectively, to enhanced σ conjugation and increased IR vibrational intensity of modes involving Si containing bonds (owing to their softness and polarity).