Self-healing Skin-like Sensors Based On Reversibly Cross-linked Polymers

Skin-like sensors have a broad application prospect in the field of flexible sensors.However,these skin-like sensors are vulnerable under repeated stretching,bending and compression during daily use,causing mechanical damage to the skin-like sensors.These injuries can destroy the structural and mechanical integrity of skin-like sensors,resulting in partial or total loss of sensing function and reducing their service life.Therefore,endowing skin-like sensors with self-healing and recycling properties is one of the most effective ways to solve this problem.Except for self-healing and recycling properties,skin-like sensors should also have excellent mechanical properties such as high strength,stretchability and tear resistance to ensure their stability during usage.Therefore,it is very important to prepare healable and recyclable skin-like sensors with high strength,stretchability and tear resistance.1.We firstly fabricate precursor polymers via free radical polymerization preparation of itaconic anhydride and triethylene glycol methyl ether methacrylate.Diamino diphenyl disulfide and propylamine further react with anhydride to prepare self-healing elastomer with high strength and high elasticity based on hydrogen bonding interactions and disulfide bonds.The glass transition temperature of self-healing elastomer is-6?C,and it has excellent thermal stability.Tensile tests show that PI(SS₅-PA₉₅)-co-PT elastomers have the best mechanical properties when the percentage of anhydride consumed by diphenyl amino disulfide is 5%and the percentage of anhydride consumed by propylene amine is 95%.The breaking strength,breaking strain,and Young's modulus of PI(SS₅-PA₉₅)-co-PT elastomers are?2.29 MPa,?566%,and?1.8 MPa,respectively.Cyclic tensile tests prove that the PI(SS5-PA95)-co-PT polymers have good elasticity and self-recovery.The damaged elastomers can restore to the mechanical properties of the intact elastomers after healing at 50?and100%humidity for 18 h.In addition,the elastomer can exihibit excellent recyclability under 85?and 4 MPa.Furthermore,by coating Ag nanoparticles on PI(SS₅-PA₉₅)-co-PT elastomer,electronic skin sensor based on PI(SS₅-PA₉₅)-co-PT can be realized.The electronic skin sensors have good sensitivity and can sense bending,touching,deep breathing and different types of human activities.2.Self-healing ionic skin sensors with high strength,tear resistance and high sensitivity can be prepared by polymerization of AA,PEGMEA,Ca²⁺,Li TFSI and UV initiator in water,followed by drying process.By changing the content of Li TFSI and Ca²⁺,the mechanical properties and sensing properties of PAx Liy-Ca Z elastomers can be regulated.The strength and elongation at break of PA1.4Li2.8-Ca7%elastomer are?0.31 MPa and?712.7%,respectively.More importantly,as an ionic skin sensor,PA1.4Li2.8-CA 7%elastomer has the highest sensitivity of 8.57.At the same time,the PA1.4Li2.8-Ca7%ionic skin sensor also shows excellent tear resistance.Due to the dynamic hydrogen bonding and coordination interactions in the PA1.4Li2.8-Ca7%ionic skin sensors,the PA1.4Li2.8-Ca7%ionic skin sensors have excellent self-healing performance.The damaged PA1.4Li2.8-Ca7%ionic skin sensors can fully restore their mechanical properties after 72 h-healing at room temperature.