Triboelectric charging of insulating polymers–some new perspectives

Tribolectric charging results from contact between surfaces, but precisely what is meant by each is not defined or understood, as they relate to charging. The recent microscopic evidence that contact charging can result from material transfer provides incentive to examine how contact charging is affected by these two factors. It is suggested that vigorous rubbing or pressing of two polymers results in transfer of deeper layers than would result from light contacts. Different layers can have substantially different compositions because polymers are typically not homogeneous as a function of depth, so contact and surface are related in this way. This could account for charge transfer between identical polymers, especially in asymmetric contacts in which the frictional force on one polymer differs from that on the other, so that material from different depths is transferred. This review outlines the roles of physics, chemistry and surface analysis in sufficient detail to focus on these subjects. It also makes suggestions how these concepts could be applied to some of the current leading edge research in this area.