Discovery of an unknown conduction mechanism in insulating polymers

Polymer dielectrics are widely used in electrical and electronic apparatus and devices because of their capability to insulate conductors, withstand high fields and suffer negligible conductive losses. Their near-to-zero conductivity has been explained in terms of long-accepted theories of electronic and ionic transport that lead to the accumulation of local net charge regions at high electric fields. Here the authors describe a previously unknown conduction mechanism consisting of small bipolar ultra-fast charge pulses crossing the polymer with the mobility, as large as, 4 to 5 orders of magnitude greater than that of the previously known. The authors show that this motion is a consequence of molecular relaxation processes triggered by the electric field locally enhanced by the pulses themselves. Pulse accumulation at the electrodes increases interface field and thus contributes substantially towards premature failure in insulating dielectrics in DC fields.