Open- and short-circuit thermally stimulated currents in ethyl cellulose (EC): polymethyl methacrylate (PMMA) blend

Mechanisms of charge generation and its persistence in one and both-side va cuum-aluminized ethyl cellulose (EC):polymethyl methacrylate (PMMA) blend t hermoelectrets, prepared under different fields (10, 25, 50 and 100 kV/cm) and temperatures (40, 60, 80 and 100 degrees C), have been analysed using s hort- and open-circuit thermally stimulated depolarization current (TSDC) t echnique. The TSDCs were recorded by reheating the samples at a linear heat ing rate of 4 degrees C/min. The TSDC thermograms of polyblends containing EC:PMMA in different weight ratio are, in general, characterized with two p eaks in lower and higher temperature regions. However, the polarity of the peaks was found to be just opposite in short- and open-circuit TSDC measure ments, Moreover, results on 97:3, 93:7 and 90:10 EC:PMMA polyblends indicat ed that the current increases with concentration of PMMA. The results indic ate the existence of heterocharge due to dipole orientation and ionic charg e drift together with the injection of charge carriers from electrodes with their subsequent localization in surface and bulk traps. Further, the chan ces of charge trapping in polyblends, at the interfaces are greater than in the individual polymers.