Deformation and failure of polycarbonate in an electric field

Electrically induced mechanical stress was produced on a monolithic polycarbonate (PC) film when subjected to an instantaneous direct current voltage using a needle-plane electrode setup. Three different experimental methods were used to investigate the electrically induced mechanical deformation on the glassy PC film, namely, morphological observation, energy loss analysis, and dielectric hysteresis study. It was found that the PC film exhibited elastic behavior at the nominal electric field below 200 MV m⁻¹, showing no indentation on the film surface. When the nominal field was above 200 MV m⁻¹, a spherical indentation was created. The depth and diameter of the deformation increased in response to the applied electric field. Subsequent thermal annealing of the deformed film revealed a recoverable “delayed elastic” and an unrecoverable “plastic” deformation. A three-stage electrically induced mechanical deformation mechanism was proposed based on the experimental results, including a correlation between the energy loss and the deformed volume. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2020 , 137, 48341.