Self-Powered and Self-Functional Cotton Sock Using Piezoelectric and Triboelectric Hybrid Mechanism for Healthcare and Sports Monitoring

Abstract

Wearable devices rely on hybrid mechanisms that possess the advantages of establishing a smarter system for healthcare, sports monitoring, and smart home applications. Socks with sensing capabilities can reveal more direct sensory information on the body for longer duration in daily life. However, the limitation of suitable materials for smart textile makes the development of multifunctional socks a major challenge. In this paper, we have developed a self-powered and self-functional sock (S2-sock) to realize diversified functions including energy harvesting and sensing various physiological signals, i.e., gait, contact force, sweat level, etc., by hybrid integrating poly­(3,4-ethylenedioxythiophene) polystyrenesulfonate (PEDOT:PSS)-coated fabric triboelectric nanogenerator (TENG) and lead zirconate titanate (PZT) piezoelectric chips. An output power of 1.71 mW is collected from a PEDOT:PSS-coated sock with mild jumping at 2 Hz and load resistance of 59.7 MΩ. The study shows that cotton socks worn daily can potentially be a power source for enabling self-sustained socks comprising wireless transmission modules and integrated circuits in the future. We also investigate the influences of environmental humidity, temperature, and weight variations and verify that our S2-sock can successfully achieve walking pattern recognition and motion tracking for smart home applications. On the basis of the sensor fusion concept, the outputs from TENG and PZT sensors under exercise activities are effectively merged together for quick detection of the sweat level. By leveraging the hybrid S2-sock, we can achieve more functionality in the applications of foot-based energy harvesting and monitoring the diversified physiological signals for healthcare, smart homes, etc.

Recent progress on flexible nanogenerators toward self‐powered systems

“…The authors applied the HBNG in sports for detecting different basketball dribbling heights (Figure A). Figure B presents a self‐powered sock that consisted of poly(3,4‐ethylenedioxythiophene) polystyrenesulfonate (PEDOT: PSS) coated TENGs and PZT PENGs . By tuning the external loading resistances, the output power of the sock could be boosted up to 66 and 137 μW under 1 Hz walking and 2 Hz jumping.…”

“…Figure 8B presents a self-powered sock that consisted of poly(3,-4-ethylenedioxythiophene) polystyrenesulfonate (PEDOT: PSS) coated TENGs and PZT PENGs. 166 By tuning the external loading resistances, the output power of the sock could be boosted up to 66 and 137 μW under 1 Hz walking and 2 Hz jumping. Combing the power generated from the PTFE based "shoe pad," the maximum power output of 1.71 mW was obtained.…”

Artificial Perception Built on Memristive System: Visual, Auditory, and Tactile Sensations

“…Although most self‐powered sensors achieve either high sensitivity or wide measurement range, they are hardly used for precise action identification . Hybrid piezoelectric–triboelectric sensors (HPTSs) have been proposed to further enhance the sensitivity and measurement range . For example, in Figure g, a piezoelectric–triboelectric sensor is composed of an ultraflexible nanopolarized microfrustum‐array PZT and PDMS film and an m‐Cu film.…”

Investigation of Low‐Current Direct Stimulation for Rehabilitation Treatment Related to Muscle Function Loss Using Self‐Powered TENG System

“…While self-powered triboelectric nanogenerator (TENG) sensors made significant impact to wearable electronics ranging from healthcare, human-machine interface, robotics, gaming, virtual reality, and augmented reality, [33][34][35][36][37][38][39][40][41][42] TENG also shows great potential to serve as both waveform generator and power supply in the implantable electrical muscle stimulation systems, considering the recent successful demonstrations of direct electrical stimulation on the cells, peripheral nerves, and brain using current output from the TENGs. On the cell level, Guo et al showed electrical stimulation using TENG output enhances neural differentiation, [43] and Long et al studied wound healing and antibiofouling using the electric field generated by TENGs.…”