Effect of Geometrical Parameters on Piezoresponse of Nanofibrous Wearable Piezoelectric Nanofabrics Under Low Impact Pressure

Piezoelectric polymers are potential energizers for wearable electronics due to the possibility of developing their yarns for various textile products. The present study is aimed at understanding the effect of geometrical parameters, viz., yarn linear density (measured as Tex), twist per meter (TPM), plying, as well as weft and warp density on the piezoelectric voltage of electrospun yarns of polyvinylidene fluoride (PVDF) polymer and poly(vinylidene fluoride)-co-trifluoroethylene] P(VDF-TrFE)] copolymer. Yarns are developed by twisting and plying electrospun nanofibers and their mechanical and piezoelectric properties are systematically investigated. Relative advantages of the yarns of the copolymer with respect to PVDF in both aligned and random fiber geometries are evaluated. The studies show that piezoresponse of the woven nanogenerators can be enhanced by decreasing Tex and increasing the TPM, the plying number, and the fabric density. A record piezovoltage of ≈2.5 V is achieved through this work. The results of the present work can be used for the fabrication of flexible and breathable nanogenerators or sensors.