Frequency and Temperature Responses

The temperature has a very complicated influence on the E-M performance of polymers. The Young s modulus of polymer decreases with the temperature, but the temperature dependence of its dielectric properties can be very different. For some of the piezoelectric and electrostrictive polymers, there is a phase transition at temperatures close to room temperature. At the phase transition temperature, the dielectric permittivity reaches its maximum and the polymer exhibits a high dielectric loss. Additionally, at temperatures around the glass transition temperature, all polymers exhibit some dielectric relaxation and elastic relaxation, resulting in a frequency dependence of material properties and a high dielectric and elastic loss. 

Due to the dielectric and elastic relaxations, the E-M response in polymers often shows strong relaxation behavior. The coefficients in the piezoelectric constitutive 

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