Piezo- and pyroelectric properties of dehydrofluorinated PVDF films

PVDF was effectively dehydrofluorinated by the reaction with hot alkali-DMSO solution. PVDF degrades to products containing c=c, c=c, and c=0 groups as revealed by the corresponding bands in the IR spectrum. Because of the formation of conjugated c=c double bonds in the polymer chain, films of degraded PVDF become darker. Films have been produced by casting onto a glass plate. These cast films were stretched and poled. The results of the measurements of the piezoelectric strain coefficient d/sub 31/ and of the pyroelectric coefficient p/sub 3/ are given in comparison with undegraded films. Moderately pyroelectric coefficients of dehydrofluorinated PVDF films and their enhanced absorbance makes them attractive for potential applications in fast pyroelectric sensors.