High-sensitivity dual-mode flexible electrooxidized cellulose-based electronic skins with compatible mechanical properties and antimicrobial activity for wide-temperature applications

Abstract

Flexible electronic skin (e-skin) is crucial for robotics, healthcare and medical monitoring, but confronts challenges like sensibility, stability and temperature endurance. Herein, a novel high-sensitivity dual-mode self-powered e-skin for temperature and strain sensing has been proposed using a cellulose-based ionogel and non-faradaic junction (NFJ) for wide-temperature applications. The ionogel, facilely prepared using the cellulose which is controllably electrooxidized without toxic solvents, has excellent temperature endurance and good adaptability to human skin by constructing highly entangled hierarchical multi-scale networks (EMSN). The tensile strength reaches 0.349 ~ 1.145 MPa, while both Young's modulus (0.542 ~ 1.057 MPa) and toughness (0.18 ~ 3.59 MJ·m^-3) are compatible from -40 to 120 ℃, comparable to human skin and the reports. Furthermore, its structural integrity and elasticity maintain at -100 and 120 °C. The e-skin can achieve dual-mode sensing and exhibit superior performance such as high sensitivity (GF=0.75), high fidelity of sensing signals at different temperatures, good stability, and antimicrobial activity. The solid-state supercapacitor using the ionogel without any other liquid electrolyte exhibits a voltage window of 0.6 V and a power density of over 210.00 W·kg^-1. It supplies a novel strategy to develop sustainable sensors with biocompatibility for harsh surroundings.