Intrinsically Conductive Bifunctional Nanocellulose-Reinforced Robust and Self-Healable Electronic Skin: Deep Insights into Multiple Bonding Network, Property Reinforcement, and Sensing Mechanism

The rapid development of intelligent electronic skin with skin-like protein structures and noninvasive adhesion to the skin has attracted attention in the field of wearable electronics. However, poor mechanical strength, narrow sensing range, and low adhesion hinder its practical applications. Herein, a multifunctional composite sensor (SCGC) was achieved by incorporating an intrinsically conductive bifunctional nanocellulose (CNFene) into a Ca2+/glycerin (GL)-modified silk fibroin (SF) matrix. The SCGC film showed robust mechanical strength (tensile strength = 76.1 MPa, elongation at break = 144.2%), wide sensing range, and excellent self-adhesion ability (strong adhesion at low temperatures even in liquid nitrogen). Especially, the bifunctional nanocellulose-reinforced electronic skin can sensitively detect small- and large-scale human motion and has high-temperature change sensitivity (the temperature sensitivity = −5.2%/°C) due to multiple interactions of the double hydrogen-bonding network and calcium ion chelation among SF/CNFene/GL/Ca2+. Therefore, this strategy has potential applications in flexible electrodes, biomimetic sensors, and temperature biosensors.