High electric field resistivity and pyroelectric properties of vinylidene fluoride‐trifluoroethylene copolymer

Copolymers of vinylidene fluoride‐trifluoroethylene P(VDF‐TrFE) exhibit large piezoelectric and pyroelectric effects. In addition to the most common application of the pyroelectric effect (radiant detection) it is possible to convert heat directly into electrical energy by pyroelectric conversion. This study reports the first measurements of high (constant) field pyroelectric effects of P(VDF‐TrFE) which are relevant to pyroelectric conversion. Electric displacement changes which result from temperature changes of the copolymer were measured for thermal cycling from room temperature to 90 °C at fields up to 1 MV/cm. The displacement changes (0.1–0.3 μ C/cm2) were dependent upon the molar ratio of the constituent monomers. The resistivity of the copolymer was also measured in the temperature range 20 to 90 °C and was found to vary from 1012 to 1016Ω cm depending on monomer ratio, temperature, field, and time. The resistivity and displacement change data are discussed in terms of predicted pyroelectric ener...