Charge distribution and transport in polymers

Experimental work on charge distributions and charge transport in polymer films is reviewed. For studying the charge distributions in the thickness dimension, thermal or acoustic techniques are used with resolutions down to /spl sim/1 /spl mu/m. The polymer samples usually are charged with corona, electron beam or thermal methods. Observation of the change of charge and polarization distributions with time allows one to draw conclusions about charge transport and charge injection phenomena. In some cases theoretical models have been established, based on excess-charge drift due to a finite carrier mobility and on charge compensation due to intrinsic or radiation-induced conductivity. Other models are concerned with the interaction of injected or intrinsic space charge with a dipole polarization. Comparisons of measured and calculated charge distributions and their change with time show the applicability of these models and shed new light on charge trapping and charge transport phenomena.