Deformation and failure of polycarbonate in an electric field

Abstract

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.

Electromechanical deformation and failure of multilayered films

“…The hold time was set at 250 milliseconds. The charging and discharging current measurements from the system in these experiments is shown in Figure 1(b), 44 which is similar to that used in the previous study. Two resistors (R 1 = 150 MΩ and R 2 = 100 kΩ) in parallel with the sample were placed in the circuit and the voltage across R 2 was recorded.…”

“…The overall energy loss up to fracture is much higher than the charge–discharge reported energies and could not be determined in these studies with the current experimental arrangement. The value for the monolithic PC film measured previously 44 is included in the figure for comparison. Also, a maximum is again observed in the center of the treeing region.…”

“…The electrode configuration employed in this study was the same as that in the previous papers 44,45 . The electrodes and sample were immersed in silicone oil to minimize the surface and corona discharge (Figure 1(a)).…”

“…Zhang, et al, 44,45 recently studied the mechanical surface deformation prior to breakdown on 18 μm thick PC and PVDF monolithic films using a needle‐plane electrode configuration and employing a rapid DC charge impulse. This work established the relationships between the charge–discharge energy loss, electric field intensity, and the electromechanical deformation.…”

“…These encouraging observations on the enhanced performance of multilayered films, enabled additional low-electric field studies focused on understanding hysteresis characteristics that allow models suggesting the importance of charge dynamics. 10,30,43 Zhang, et al, 44,45 recently studied the mechanical surface deformation prior to breakdown on 18 μm thick PC and PVDF monolithic films using a needle-plane electrode configuration and employing a rapid DC charge impulse. This work established the relationships between the charge-discharge energy loss, electric field intensity, and the electromechanical deformation.…”