Electrospinning of poly(γ-benzyl–α,L-glutamate) microfibers for piezoelectric polymer applications

One of the latest developments in the field of piezoelectric polymers is the use of poly(γ-benzyl-α,L-glutamate) (PBLG), a poly(amino acid) that can be poled along its α-helical axis and fabricated into thermally stable piezoelectric microfibers via electrospinning. This study demonstrates a method for improving the piezoelectricity of electrospun PBLG microfibers by controlling the orientation of fibers using a method based on a concentrated electric field. The piezoelectricity is verified via customized quasi-static and dynamic measurement methods, while the correlation between fiber alignment and the piezoelectric constant, d₃₃, in the longitudinal mode of the electrospun PBLG fibers is investigated. When the level of alignment was varied from 50% to 90%, the piezoelectric constant increased linearly, showing a maximum d₃₃ of 27 pC N⁻¹ and a maximum force sensitivity of 65 mV N⁻¹ at peak alignment. A fabricated flexible prototype based on electrospun PBLG fibers provides a new solution for the use of PBLG fibers in wearable energy harvesters or composites based on piezoelectric polymer fibers. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018, 135, 46440.