In this work, we propose a facile method of fabricating electrospun graphene-dispersed PVAc nanofibrous membrane-based piezocapacitive sensors for applications in IoT-enabled wearables and human physiological function monitoring. A series of electrical and material characterization experiments were conducted on both the pristine and graphene-dispersed PVAc nanofibers to understand the effect of graphene addition on nanofiber morphology, dielectric response, and pressure sensing performance. Dynamic uniaxial pressure sensing performance evaluation tests were conducted on the pristine and graphene-loaded PVAc nanofibrous membrane-based sensors for understanding the effect of two-dimensional (2D) nanofiller addition on pressure sensing performance. A marked increase in the dielectric constant and pressure sensing performance was observed for graphene-loaded spin coated membrane and nanofiber webs respectively, and subsequently the micro dipole formation model was invoked to explain the nanofiller-induced dielectric constant enhancement. The robustness and reliability of the sensor have been underscored by conducting accelerated lifetime assessment experiments entailing at least 3000 cycles of periodic tactile force loading. A series of tests involving human physiological parameter monitoring were conducted to underscore the applicability of the proposed sensor for IoT-enabled personalized health care, soft robotics, and next-generation prosthetic devices. Finally, the easy degradability of the sensing elements is demonstrated to emphasize their suitability for transient electronics applications.

In this work, the applicability of electrospun carbon nanofiber (CNF) films in forming flexible, ultra-lightweight, linear yet inexpensive skin-like sensors is demonstrated by fabricating piezoresistive sensors for apparel integrable human motion monitoring and large-area tactile sensing applications. For the first time, an artificial skin sensor system capable of both proprioceptive tactile sensory perception and gesture identification is demonstrated utilizing CNF bundles. Strain and pressure sensing performance of piezoresistive CNFs integrated into various sensor designs are experimentally tested through a series of tests involving quasi-static tactile sensing and comprehensive human motion monitoring tasks. To demonstrate the mimicry of proprioceptive perception, a gesture sensing smart glove comprising of 5 thin-film sensors conformally mounted and secured on a soft nitrile glove was developed and tested for 14 different hand gestures. Furthermore, a large area 16-point touch-sensitive artificial skin was proposed and comprehensive tests were conducted to demonstrate the usability of the proposed sensing element in developing skin-inspired large area 2D pressure sensors. Finally, a smart system comprising of five identical strain sensors mimicking proprioceptors and tactile sensors is conceptualized which has potential for recreating the sense of touch in myoelectric prosthetic skins.