Fast charge pulses: The evidence and its interpretation

Cross-linked polyethylene and flexible epoxy resin samples have shown a conduction mechanism, never observed before, consisting of repeated ultra-fast charge pulses travelling across insulation with much higher mobility those of traditional charge carriers. This phenomenon seems to be governed by mechanical relaxation of polymer chains. Indeed, materials mechanically rigid, such as e.g. glassy epoxy, do not exhibit this behavior, unless addition of nanoadditives can increase partially the material flexibility, thereby allowing charge pulses to be incepted. Moreover, it was observed that the application of an external mechanical force can influence significantly fast charge pulse features. This would demonstrate that such a conduction mechanism is not governed by traps, but it is driven by the contribution of polarization and the resultant electromechanical compression. This is able to generate solitons, in the form of charge pulses, whose amplitude, mobility and repetition rate are influenced by the mechanical properties of the polymer. © 2013 IEEE.