Tunable Buckled Beams with Mesoporous PVDF-TrFE/SWCNT Composite Film for Energy Harvesting.

By incorporating mesoporous piezoelectric materials and tuning mechanical boundary conditions a simple beam structure can significantly take advantage of limited mechanical displacements for energy harvesting. Specifically, we employed a mesoporous PVDF-TrFE composite thin film mixed with single-wall carbon nanotubes to improve the formation of the crystalline phase in this piezoelectric polymer. The film was then patterned on a thin buckled beam to form a compact energy harvester, which was used to study the effects of two boundary conditions, including the end rotation angle and the location of a mechanical stop along the beam. We carefully designed controlled experiments using mesoporous PVDF-TrFE film and PVDF-TrFE/SWCNT composite films, both of which were tested under two cases of boundary conditions, namely, the rotation of the end angle and the addition of a mechanical stop. The voltage and current of the energy harvester under these two boundary conditions were, respectively, increased by approximately 160.1% and 200.5% compared to the results of its counterpart without imposing any boundary conditions. Thereby, our study offers a promising platform for efficiently powering implantable and wearable devices for harnessing energy from the human body which would otherwise have been wasted.