A Continuous Manufacturing Approach for Aligned PVDF Nanofiber Yarns with Enhanced Mechanical and Piezoelectric Properties.

Electrospun poly(vinylidene fluoride-co-hexafluoropropylene) (PVDF-HFP) nanofibers possess desirable mechanical and piezoelectric properties, making them promising candidates for smart textiles if they can be assembled into continuous yarns. This study presents a manufacturing approach that enables the production of electrospun PVDF-HFP nanofiber yarns using an automated parallel track system and an adjustable roll-to-roll collector. Results show that this approach has potential for PVDF yarn manufacturing on a commercial scale. Electrospun yarns have previously been fabricated with self-bundling methods, but current technologies are limited by production limitations such as the lack of tight control over assembly parameters and the absence of a postdrawing process. Postdrawing was applied here to individual fibers before yarn spinning to enhance fiber strength by over two times and yarn strength by 39%. The piezoelectrical performance of yarns was enhanced by up to 45% with postdrawing. Continuous PVDF-HFP yarns with specific strength approaching 50,000 N m/kg and a relative β phase content of 97% are promising candidates for piezoelectric nanofiber-based smart textiles, which can be integrated into various wearable devices and intelligent garments.