Textured nanofibers inspired by nature for harvesting biomechanical energy and sensing biophysiological signals

Flexible electronics are emerging as a promising new platform for wearables; however, their practical utility is hindered by the limited battery life of electronic devices and the need for frequent battery replacements. Here, we report self-powered, flexible, permeable, tough, and lightweight biomechanical energy harvesting and biophysiological sensing devices using textured nanofibers for wearable electronics applications. The textured structure draws inspiration from two major sources of nature: the interior porous structure of jute fibers and the rough bark texture of trees. Interior pores are introduced to the nanofibers to increase compressibility and breathability like jute fibers. The inspiration from the rough bark texture also leads to a wrinkled surface morphology of the nanofibers to expand the surface area and consequently enhance toughness. To design and fabricate such a textured structure, the vapor-induced phase separation mechanism and electrospinning technique are employed within a controllable high humidity environment. Consequently, the textured nanofiber-based devices exhibit a well-rounded performance in electrical, mechanical, and physical properties, specifically demonstrating a significantly enhanced piezoelectric performance with more than two-fold electrical generation. These textured devices not only effectively harvest biomechanical energy from human movement but also demonstrate sensing capability for self-powered multifunctional biophysiological monitoring applications by leveraging the same piezoelectric mechanism. The novel design strategy for the textured nanofibers and their resultant balanced performance promotes the versatility and practical applicability of piezoelectric fibrous energy harvesting and sensing devices, contributing to the development of next-generation flexible and wearable electronics.