Recyclable, ultralow-hysteresis, multifunctional wearable sensors based on water-permeable, stretchable, and conductive cellulose/PEDOT:PSS hybrid films

Abstract

The demand for eco-friendly wearable sensors is driving the exploration of stretchable, biocompatible, conductive, and recyclable materials for detecting electromechanical signals from the human body. Herein, a straightforward method for producing stretchable, conductive, water-permeable, low-hysteresis, and recyclable hybrid films is proposed, based on a combination of hydroxyethyl cellulose (HEC) and lab-synthesized poly(3,4-ethylene dioxythiophene):poly(styrene sulfonate) (L-PEDOT:PSS). Fine-tuning the film composition yields a stretchable and high-performance sensing material with ultralow hysteresis. The composite film is stable even when subjected to 5000 strained stretch-release cycles and exhibits an efficient thermoresistive response. The on-skin sensor derived from the HEC/L-PEDOT:PSS composite conforms to diverse body movements without sacrificing structural integrity. The sensors exhibit high sensitivity, stability, rapid response times, and low power consumption, enabling efficient monitoring of subtle human activities, such as handwriting, frowning, air flow, and even diaphragmatic breathing. Our sensors not only demonstrate excellent recycling, but also exhibit almost complete recovery of both mechanical and electrical functions upon recycling. To the best of our knowledge, this is the first report on the HEC/PEDOT:PSS composite as a multifunctional and recyclable on-skin sensor. HEC/L-PEDOT:PSS composite films are promising for the advancement of on-skin sensors and will contribute to the development of high-performance, eco-friendly, and zero-waste wearable sensors. This study presents a method to prepare stretchable, conductive, water-permeable, and recyclable hybrid films using hydroxyethyl cellulose and PEDOT:PSS for eco-friendly sensors, with high sensitivity, low power consumption, and low hysteresis.