Poling-free spinning process of manufacturing piezoelectric yarns for textile applications

Abstract

This report describes a newtwist-spinning process for the manufacture of piezoelectric yarn without the need for additional poling processes. Poly(vinylidene fluoride-trifluoroethylene) (PVDF-TrFE) nanofibers were first electrospun and organized into a web structure. Using rotational and translational motors, the nanofibers of the web were pulled and stretched and, finally, twisted into piezoelectric yarns. The crystallinity, beta phase ratio, and mechanical and piezoelectric properties of these twist-spun piezoelectric yarns were characterized to assess the effects of the twist-spinning operation on their microstructure and performance. Twist-spun piezoelectric yarns that had undergone high degrees of stretching exhibited enhancements in both crystallinity and beta phase ratio by 83% and 12%, respectively. In contrast, high stretching reduced the tensile strength and modulus of the yarns due to small surface angles. The twist-spun piezoelectric yarn with the highest beta phase ratio and lowest modulus attained in this study yielded a piezoelectric potential and piezoelectric voltage constant of 500 mV and 0.412 mVm/N, respectively.