Conductivity states changes in plasticized PVC films near breakdown threshold voltages values

TL;DR

This study investigates the nonlinear conductivity changes in thick PVC films near breakdown voltages, revealing reversible high-conductivity states and dynamic responses under strong electric fields.

Contribution

It provides new insights into the nonlinear and reversible conductivity transitions in thick PVC films near breakdown thresholds, expanding understanding beyond thin film behavior.

Findings

Resistance shows strong nonlinearity near breakdown.

Reversible transitions between high and low conductivity states.

Polymer films act as relaxation generators with increasing frequency.

Abstract

The near threshold "soft breakdown" measurements of PVC films conductivity are investigated. In a wide range of external electric field strength for various rather thick (>20 mkm) PVC films the resistance shows strong nonlinearity and seems to enter high conductive state close to the breakdown threshold. For our "thick" films boundary conditions electrode surface specifics should not be so important as in thin polymer films experiments. Both fast, instant mechanisms of nonlinearity, and effects of accumulation and delay responce were observed. The phenomena corresponding to reversible transitions in a state with rather high conductivity, seems to be similar to ones registered earlier in thin layers of some broad-bandgap polymers. In a range of relatively low field intensity, far from a threshold breakdown, as a result of reversible switches between normal and high resistivity states a polymer film in a standard measuring cell formed a relaxation generator giving a loud enough sound signal with frequency increasing with the increase of external field.