Effect of trapped space charge on mechanical deformation induced by electric field

An organic insulating film of polyethylene naphthalene 2,6-dicarboxylate (PEN) was characterized by two complementary techniques: the mechanical deformation of the sample surface, induced by the application of an electric field, was obtained by an image correlation technique named DIC (Digital Image Correlation) and the space charge distributions in the thickness direction were measured by FLIMM (Focused Laser Intensity Modulation Method). The validation of the DIC method, which consists of a following of the successive positions of the surface patterns of the sample, is presented. To validate the algorithms and evaluate the performance of the technique, it was applied to computer-simulated speckle images. In a second step, the experimental system was applied to measure the mechanical deformations of a PEN film previously charged by an electric field in order to have space charge accumulation. This space charge accumulation was quantified by FLIMM. The results show that the mechanical behavior of the sample is modified by the presence of space charge.