The effect of dipole scattering on intrinsic breakdown strength of polymers
The introduction of dipoles into a polymer can enhance dipole-induced scattering which tends to "cool" hot electrons and thereby inhibits runaway of hot electrons. A theoretical analysis of electron scattering by dipoles and phonons is presented which provides the basis for explaining temperature dependence of breakdown field on the basis of the dominant scattering process as a function of temperature. By performing electron mobility calculation in non-polar and polar polymers, a quantitative correlation between chemical composition and intrinsic breakdown strength can be established. Calculation of dipole scattering limited electron mobility can be used to assess the effect of dipole scattering on the intrinsic breakdown field of polymers.