Triboelectricity and some associated phenomena

Abstract

Examples of phenomena associated with triboelectricity include the charged nature of amber rubbed with silk, sparks from flint striking steel, frictional van de Graaff generators, lightning, the explosion in an unloaded petroleum tanker during cleaning of the hold with a high pressure water spray, and the clinging of extruded polyethylene film foodwrap to a dish. Separation of positive and negative charges is the common feature. Triboluminescence and the phenomenon called sonoluminescence (the emission of light from a liquid when acoustic energy is absorbed by small, trapped gas bubbles) probably also involve separation of charges. In this review, some recent experiments are briefly discussed and the current problems of interpretation are pointed out. Electrorheology is concerned with field enhanced dipole–dipole interaction in relation to the mechanical stress required to achieve separation. A recent study of highly polarisable microparticles, made by coating small glass spheres with Ni metal followed by a thin insulating layer of TiO₂ , is described.