Correlations between the structure and the electret behavior of PVDF/PMMA-alloys

The influence of the structure of alloys of semicrystal line poly(vinylidene fluoride) (PVDF) and amorphous poly(methyl methacrylate) (PMMA) on the electret behavior was investigated in detail. The samples were corona charged and subsequently studied by means of the open-circuit thermally-stimulated-current (TSC) technique. In addition, direct current conductivity measurements were performed. The TSC thermograms of the amorphous alloys exhibit a dipole orientation peak at the glass transition, the position of which is sensitive to composition of the blend. A second TSC peak is found to be related to conductivity, presumably ion transport controlled by free volume. A tentative interpretation of the TSC of the semicrystal-line alloys is based on the occurence of Maxwell-Wagner-Sillars charges at the interface between crystalline and amorphous regions.