Effects of temperature on the aging rate of piezoelectric polymer

Abstract

Results of aging measurements at 20°C, 57°C, and 66°C are presented for commercially available piezoelectric polymer (28-μm thick, poled polyvinylidene fluoride). The g31 (electric field/stress) and d31 (charge density/stress) piezoelectric constants were measured by a static dead weight tension test. The relative dielectric constant K33T was obtained from a 1-kHz capacitance measurement. At room temperature (20°C), aging rates of 10%/time decade for g31, 15%/time decade for d31, and 7%/time decade for K33T were obtained over a 100-day period from date of poling. Values of g31 and K33T were measured (at room temperature) for samples held at 57°C and 66°C for 100 days starting at 400 days from poling. For the 57°C case, g31 values at 401, 410, and 500 days showed a 3%, 10%, and 16% decrease over the 400-day value. The 66°C case showed decreases of 16%, 19%, and 21% in g31 over the same time period. No change in K33T was observed for either of these cases. [Work supported by R. R. Smith, Code 302, Naval Ocean Systems Center, San Diego, CA.]