The role of material behavior in the performances of electroactive polymer energy harvesters

Electroactive polymer energy harvesters are promising devices for the conversion of mechanical work to electrical energy. The performances of these devices are strongly dependent on the mechanical response of the polymeric material and on the type of electromechanical cycle, and these are limited by the occurrence of dielectric breakdown, compression induced wrinkling and electromechanical instability (pull-in). To identify the optimal electromechanical cycle that complies with all of these limitations, we set-up and solve a constraint optimization problem and we critically discuss the influence of material behavior of the polymer in the optimal performances of the energy harvesting device. Finally, we show that if the rate-independent dissipative behavior of the polymer (Mullins effect) is neglected, the optimization procedure may lead to quite unsatisfactory predictions: by making reference to explicit experimental data from literature we show that an optimal harvesting cycle deduced by neglecting the Mullins effect is far from being optimal when this is taken in consideration.