Transient currents in ultra-thin polyester films

Experimental evidence is presented that allows one to define a simple procedure for obtaining reproducible and reliable measurements of the transient and steady-state electrical conduction in ultrathin polyester films without any previous electrical, mechanical, or thermal treatments. Such treatments, which are usually recommended for obtaining reproducible results, in fact induce pronounced charges in the matrix morphology and crystallinity, thus preventing a full characterization of industrial films under realistic storage conditions. It appears from the present measurements that the previously encountered difficulties could arise from the existence of mechanical stresses of microtears induced in the measuring area, which can be easily avoided by using a two-electrode configuration with opposite lateral contacts