Polyethylene under electrical stress

Fifty years ago, the concept of an intrinsic electric strength for insulating solids was fashionable. It was supported by the sophisticated theoretical models of von Hippel, Frohlich and others for the interaction of electrons with crystal lattices in an electric field. The models came to be applied, rather implausibly perhaps, to polymers such as semi-crystalline polyethylene (PE). In that climate, the work of van Roggen on the high-field conductivity of single lamellar crystals of PE was notable. Since then, the picture of the insulating properties of PE has had to be painted with an increasingly complex palette in which the electrical elements have had to be supplemented by mechanical, chemical, and optical ones. The present review of the conducting properties of the polymer considers these other features, but concludes that the fundamental characteristics of the lamellar PE crystal are still the determining factors.