Open circuit thermally stimulated discharge current measurement on PMMA:PEMA:PVDF ternary blends

Abstract

Ternary blends of Poly (methylmethacrylate), Poly (ethlymathacrylate) and poly (vinlylidenefluoride) were prepared using solution cast technique. The open circuit thermally stimulated discharge current (OC-TSDC) technique was used to study the hetero charges, homo-charges and interfacial charge formation in ternary system. The present investigation was carried out on bilaterally metallized electret. The thermograms were characterized with multiple peaks in the temperature ranges from 40, 60, 80 and 100oC and the current direction was, in general, found to correspond to homo- charge, i.e., the same as that during charging with a few exceptions. The resultant current polarity corresponds to the dominant charging process. To distinguish between homo-charge decay by ohmic conduction and space charge limited drift in an open circuit, homocharge magnitude is changed by varying the polarizing voltage. Decay of ohmic conduction is independent of the initial charge; however, space-charge-limited (SCL) drift dependence on the injection level. A high initial charge will enhance the drift because it increases the field that drives the charges to adhering back electrode. This proves unequivocally that the, ρ peak is caused by the motion of excess charges and not by dipole relaxations, hence, the useful for microelectronics and many special purpose insulation.