Low-temperature measurements of the specific heat capacity of a thick ferroelectric copolymer film of vinylidene fluoride and trifluoroethylene

Abstract

The specific heat capacity c(p) of a 110 mu m thick and partially crystallized (similar to 77% ) ferroelectric copolymer film of vinylidene fluoride ( PVDF ) ( similar to 75 mol % ) and trifluoroethylene ( similar to 25 mol % ) was measured from 2 to 20 K. The temperature dependence of c(p)/T(3) reveals a shallow hump, centered at similar to 5 K, consistent with non- Debye behavior of semicrystalline materials. These cp data were used, in conjunction with previous measurements of the pyroelectric coefficient vertical bar p'vertical bar, to infer the temperature profile of the macroscopic Gruneisen parameter based on ratios of vertical bar p'vertical bar/c(p). Comparisons with similar data for PVDF are consistent with a correlation between anharmonicity of the interaction potential and excess specific heat capacity.