Fabrication And Sensing Properties Of Self-healing Mxene Nanocomposite Hydrogels

Recently,standing at the dawn of the information era,flexible sensors are the basis of the rapidly growing field of physiological sensors,bioelectronic interfaces,electronic skin artificial intelligence and personal healthcare monitoring.The hydrogels are intrinsically stretchable ionic conductors primarily formed by three-dimensional hydrophilic network along with water.Meanwhile,the hydrogels are compatible with human tissues in terms of mechanical properties and conductive mechanism,which is the ideal materials for flexible electronics.The emerging of MXene nanosheets are famous for excellent mechanical strength,exceptional hydrophilicity,and rich surface chemistry.Incorporating MXene nanosheets into hydrogels could takes full advantages of the hydrogels and MXene nanosheets to bring about both improved properties and exciting novel functionalities for enhanced performances in various applications.In this situation,we have designed the healable,degradable and conductive MXene nanocomposite hydrogel for multifunctional epidermal sensor and the self-healing,adhesive MXene hydrogel-based pressure sensor.The details are as follows:1.The MXene-PAA-ACC hydrogel is prepared from the conformal coating of MXene nanosheets network by the polymer networks of poly(acrylic acid)(PAA)and amorphous calcium carbonate(ACC)with fast self-healing ability(0.2 s),great biocompatibility,and robust degradability.Furthermore,the MXene-PAA-ACC hydrogel can be fabricated as multifunctional sensor to monitor multiple physiological stimuli including blood pulse with wide strain range(0.3%-450%)and high sensitivity(Gauge Factor=10.79),and detect the electrophysiological signals(such as the electromyogram(EMG)and electrocardiogram(ECG)signals)of human wirelessly in real-time,which shows application potential in electronic skins and personalized healthy diagnosis.2.A self-healing and self-adhesive MXene nanocomposite double-network hydrogel is fabricated by immersing MXene nanosheets into the double networks consisting of phenylboronic acid grafted sodium alginate(Alg-PBA),tannic acid(TA),and polyacrylamide(PAAm).Benefiting from the double network with MXene nanosheets,the hydrogel possessed an excellent self-healing and mechanical capability.Meanwhile,the catechol groups of the TA endowed the hydrogels great self-adhesive ability.In addition,the hydrogel can be prepared as a wearable pressure sensor to detect human motion with wide range(2.63 kPa-59.22 kPa)and high sensitivity(0.158 kPa-1),which shows tremendous potential applications for intelligent monitoring and human-machine interfacing.