Energy harvesting performance of piezoelectric electrospun polymer fibers and polymer/ceramic composites

The energy harvesting efficiency of electrospun poly(vinylidene fluoride), its copolymer vinylidene fluoride-trifluoroethylene and composites of the later with barium titanate ceramic fillers on interdigitated electrodes has been investigated. Ceramic fillers of 500 (tetragonal), 100 (cubic) and 10 nm (cubic) have been used. Further, a study of the influence of the electrospinning processing parameters on the average size of the composites fibers has been performed. It is found that the best energy harvesting performance was obtained for pure poly(vinylidene fluoride) fibers, with power outputs up to 0.02 W and 25 W under low and high mechanical deformation. The copolymer and the composites show reduced power output mainly due to increased mechanical stiffness, the power output of the composites being better for the nonpiezoelectic smaller fillers. The obtained values, among the largest found in the literature, the easy processing and the low cost and robustness of the polymer, demonstrate the applicability of the developed system.This work is funded by FEDER funds through the "Programa Operacional Factores de Competitividade – COMPETE" and by national funds arranged by FCT- Fundação para a Ciência e a Tecnologia, project references NANO/NMed-SD/0156/2007, PTDC/CTM/73030/2006, PTDC/CTM/69316/2006 and PEST-C/FIS/UI607/2011. The authors also thank support from the COST Action MP1003, 2010 ‘European Scientific Network for Artificial Muscles’. J.N.P., V.S. and V.C. thank the FCT for the SFRH/BD/66930/2009, SFRH/BPD/63148/2009 and SFRH/BD/48708/2008 grants respectively