The effect of acetophenone coating on the surface potential of LDPE films due to residual charges

We studied the effect of acetophenone coating on the surface potential of the low-density polyethylene (LDPE) films which had been inserted between plane electrodes after the removal of the upper brass disk electrode. The results for the films with coating were compared with those without coating. The polarity of the surface potential for the uncoated films was always the same as that of the applied step voltage which had been subjected to the upper electrode and then shorted, and the absolute value of the surface potential tended to increase to a constant value of about 600 V with increasing the applied voltage and also with the short circuit time for both polarities of applied voltage. The surface potential for the coated films was usually lower than that for the uncoated film and the value tended to be scattered from sample to sample. Sometimes, opposite polarity to the applied voltage was observed, even though the height was low. The increase in the short circuit time decreased the surface potential, unlike the case without acetophenone coating. These results were discussed on the basis of the charge distribution in the bulk of LDPE film.