Preparation And Strain Sensing Performance Study Of Self-healing Polymer Eutectic Gel

Eutectic gel based on deep eutectic solvents have a wide range of applications in wearable flexible sensors,health detection,human-computer interaction,ionic skin,artificial muscles and energy collection devices due to their good conductivity,high and low temperature resistance and biocompatibility.However,the problems of poor mechanical properties,lack of self-healing and adhesion of eutectic gel reported so far have seriously affected their further device applications.Therefore,with the help of molecular self-assembly strategy,this paper is committed to building eutectic gel with good mechanical properties,self-healing and adhesive properties,and exploring its application in the field of flexible strain sensors.The main research work is as follows:(1)Preparation of high tensile and self-healing polyvinylimidazole-based eutectic gelIn this chapter,PVI-DES eutectic gel is prepared by one pot method,and conductive gel strain sensor is constructed for human movement monitoring.The polymerization of vinylimidazole(VI)monomer was initiated by UV light,and N,N ’-methylene diallyl(MBA)was used as crosslinking agent to form a physical cross-linked flexible three-dimensional network.Four hypoeutic solvents(choline chloride/urea,choline chloride/ethylene glycol,choline chloride/glycerol,choline chloride/1,3-propylene glycol)were used as dispersing medium.Use its hydrogen bonds to further strengthen the network.The resulting eutectic gel has good mechanical properties(fracture stress 0.49 MPa,fracture strain 2310%,toughness 3.9MJ·m-3)and self-healing performance(the highest self-healing rate is 88.9%).(2)Study on low temperature resistance,adhesion and strain sensing performance of polyvinylimidazole-based eutectic gelPolyvinylimidazolyl(PVI-Ch Cl-Gly)eutectic gel shows excellent antifreeze performance(no icing at-80 ℃),self adhesion(adhesion strength on the skin reaches 13.6 k Pa)and strain responsiveness(GF=7.08).The assembled strain sensor can accurately monitor human movement(finger bending angle,wrist and elbow)signals.Meanwhile,the cyclic stretching behavior of the gel can also be monitored at low temperatures(-40 ℃).(3)Preparation and performance study of polyvinylpyrrolidone-based eutectic gel with high tensile strength,strong adhesion and self-healingPolyvinylpyrrolidone based eutectic gel was prepared with vinyl pyrrolidone(NVP)as monomer,polyethylene glycol diacrylate(PEGDA)as crosslinking agent,and deep eutectic solvent choline chloride-urea as dispersion medium.The eutectic gel has good tensile properties(elongation at break up to 1371%),self-healing properties(self-healing rate of 71.4%),and a wide range of use temperatures(-20 ℃ to 100 ℃).Because gel network contains a large number of carbonyl functional groups,it can form strong hydrogen bonding with various solid surfaces(such as aluminum,glass,plastic,steel,etc.),which endows eutectic gel with excellent adhesion performance on the surface of the substrate(the interface adhesion strength on the glass reaches314.6 k Pa).In addition,by triggering the physical diffusion of urea molecules to the surrounding liquid environment,the eutectic gel can achieve underwater adhesion(the interface adhesion strength on the plastic reaches 65.3 k Pa).