Enhancement of piezoelectric performance and mechanical strength by designing esterified lignin-based polyacrylonitrile membrane for piezoelectric sensor

Improving the piezoelectric and mechanical properties of polymer piezoelectric materials is an urgent research work for their application as piezoelectric materials. Thus, in this work, a new polymer piezoelectric material, esterified lignin-modified polyacrylonitrile (PAN/CEHL-PTMG), is successfully synthesized and the related piezoelectric composite nanofiber membrane is prepared by electrospinning. The structure of the membranes is well characterized by Fourier transform infrared spectrometer (FTIR), X-ray diffractometer (XRD), field emission scanning electron microscopy (SEM). The output voltage can reach as high as 1.47 V (64.63% higher than that of the pure polyacrylonitrile membrane) by optimizing the spinning solution (2% esterified lignin). The results indicated that the piezoelectric property of polyacrylonitrile (PAN) is remarkably improved by the incorporation of esterified lignin (CEHL-PTMG). In addition, a simple energy-conversion performance test is conducted, through which the prepared piezoelectric elements with PAN/CEHL-PTMG show the mechanical movement of the arm and finger. It is verified that the PAN/CEHL-PTMG piezoelectric element can complete the energy conversion well in practical application. The results indicated that an appropriate amount of CEHL-PTMG was conducive to the transformation of the planar sawtooth conformation in the microstructure of the polyacrylonitrile nanofibers. Meanwhile, mechanical tests exhibited that the CEHL-PTMG also could effectively enhance the tensile strength and elongation of the membranes. Graphical abstract