Electrostrictive polymers for mechanical energy harvesting

Recent advances in electroactive polymers including high field induced strain, high elastic energy density (∼1 J/cm ³), and relatively high energy conversion efficiency, approaching those of natural muscles, create new opportunities for many applications. Harvesting electric energy from mechanical sources such as a soldier during walking is one such example. Several electroactive polymers developed recently are briefly reviewed. The paper further presents analysis on the key steps in achieving energy harvesting effectively. It is shown that one may make use of smart electronics to modify the electric boundary conditions in the electroactive polymers during the energy harvesting cycle to realize higher energy conversion efficiency in the systems compared with the efficiency of the material itself. Due to the fact that the energy density of the electromagnetic based energy harvesting devices scales with the square root of the device volume, the paper shows that the electroactive polymers based energy harvesting devices exhibit higher energy density and therefore are more suitable for this application.