Highly Sensitive Oxidation-Resistant Degradable Janus Piezoresistive Electronic Skin for Sustainable Wearable Electronics

Abstract

Wearable sensors enable fast and accurate monitoring of physiological signals, with broad applications in electronic skin (e-skin), biomedical engineering, and human–machine interfaces. However, their proliferation raises concerns about electronic waste. To mitigate this waste, biodegradable polymers have been used to develop eco-friendly sensors. However, various challenges persist, including low conductivity, limited sensitivity, and poor stability. We introduce a degradable cellulose paper e-skin coated with Ti3C2Tx MXene and poly(3,4-ethylenedioxythiophene)–polystyrene sulfonate (PEDOT:PSS) to overcome these challenges. The MXene/PEDOT:PSS-coated cellulose paper piezoresistive e-skin demonstrates ultrahigh sensitivity (19.27 kPa−1), a wide working range (0–40 kPa), linearity at low and high pressures, long-term stability (5,600 cycles), and exceptional oxidation resistance (>22 days) owing to the stabilizing effect of PEDOT:PSS on MXene. In addition, the developed e-skin has a hydrophilic contact surface with biological skin, and its external surface is highly hydrophobic, exhibiting Janus wettability that enhances its performance. Moreover, the e-skin achieves high-performance human motion monitoring by detecting both subtle and vigorous movements, such as joint flexions, vocal cord vibrations, and other motions. The developed piezoresistive e-skin may find applications in diverse fields, such as human–machine interfaces, robotics, e-skin, and wearable sensors by enabling precise and reliable stimuli detection.