Biocompatible Multifunctional E-Skins with Excellent Self-Healing Ability Enabled by Clean and Scalable Fabrication

Electronic skins(e-skins) with an excellent sensing performance have been widely developed over the last few decades.However,wearability,biocompatibility,environmental friendliness and scalability have become new limitations. Self-healing ability can improve the long-term robustness and reliability of e-skins. However,self-healing ability and integration are hardly balanced in classical structures of self-healable devices. Here,cellulose nanofiber/poly(vinyl alcohol)(CNF/PVA),a biocompatible moisture-inspired self-healable composite,was applied both as the binder in functional layers and the substrate. Various functional layers comprising particular carbon materials and CNF/PVA were patterned on the substrate. A planar structure was beneficial for integration,and the active self-healing ability of the functional layers endowed self-healed e-skins with a higher toughness. Water served as both the only solvent throughout the fabrication process and the trigger of the self-healing process,which avoids the pollution and bioincompatibility caused by the application of noxious additives. Our e-skins could achieve real-time monitoring of whole-body physiological signals and environmental temperature and humidity. Cross-interference between di erent external stimuli was suppressed through reasonable material selection and structural design. Combined with conventional electronics,data could be transmitted to a nearby smartphone for post-processing. This work provides a previously unexplored strategy for multifunctional e-skins with an excellent practicality.

Flexible Piezoresistive Sensors based on Conducting Polymer-coated Fabric Applied to Human Physiological Signals Monitoring

This paper describes a flexible pressure sensor based on polypyrrole(PPy)-Cotton composites,in which PPy is grown on cellulose fibers of cotton pads via an in situ vapor growth method,which is beneficial to the homogeneity of the composites.The resulting devices exhibits rapid response and recovery speed,the response and recovery times are 220 ms and 240 ms,respectively.The optimal PPy-Cotton Pads(PCPs)sensor shows low detection limit,which is about 50 Pa.At the same time,it exhibits excellent durability in the measurement of repeated loading-unloading pressure over 1000 cycles.The resultant sensor can be attached on different positions of body and applied to recording physiological signals,such as wrist pulse,vocal cord vibration,respiration and eyes blinking.Finally,a 4×4 pressure sensor array shows that the PCPs sensor has capability in pressure distribution detection and represents great potential in the fields of wearable electronics and biomedical devices.