Temperature Effect on Electrical Characteristics of Negative DC Corona Charged Polyimide Films

The study of the effect of sample temperature on the electric properties of PI films has been investigated. Surface potential decay (SPD) measurements on PI (Kapton HN, thickness: 50 mu m) films were measured, after negative corona discharge, as a function of sample temperature varying from 27 to 80 degrees C. The measurements showed significant increase in the SPD rate with increasing sample temperature. Surface potential profile, return potential appearing after charge neutralization and charging current characteristics have been experimentally recorded for different sample temperatures in order to interpret SPD evolution at high sample temperature. The SPD curves were analyzed by fitting a bi-exponential decay Equation according to the presence of two different decay mechanisms related to shallow and deep traps. The distributions of trapped charges are obtained for different sample temperatures.