Preparation And Properties Of Conductive Hydrogel Based On MXene

In recent years,the development and application of biological intelligent sensing technology has penetrated into our life.However,low mechanical properties,inflexible signal transmission and insensitive signal output limit their development in the field of sensors.Mxene,a new 2D material,has attracted extensive attention because of its high electron mobility and energy storage between nanosheets.Therefore,researchers have introduced it into polymer hydrogels,so that the problems faced by the current sensing technology can be effectively solved.In this paper,by introducing MXene into the hydrogel network,it is found that MXene not only improves the conductivity and mechanical properties of hydrogels,but also provides new functional responsiveness for hydrogels,avoiding the clash between various functions of hydrogels.1.A conductive hydrogel with high toughness,elasticity and pressure sensitivity was prepared.The hydrogel is made by combining MXene nanosheets into a polymer network consisting of polyvinyl alcohol and poly（N-hydroxyethyl acrylamide-co-acrylic acid）through simple synthesis process without complex molecular design or multi-step functionalization.The hydrogen bonds on the flexible copolymer chains provide resistance to the deformation of the hydrogel.Further freezing/thawing treatment promotes the formation of polyvinyl alcohol microdomains,as a crosslinking agent for the amorphous hydrogel network,thus enhancing the mechanical strength of the hydrogels.The results showed that the hydrogel had good mechanical strength,fracture strength as high as 1.1 MPa,toughness up to 3.08MJ/m~3,and high sensitivity（GF=6.41）.The thixotropic sensor assembled by the hydrogel can perceive the multiscale movement of human body and local micropressure changes in writing which has broad application prospects in the field of human motion monitoring and writing information encryption.2.A super stretched conductive hydrogel composed of N-hydroxyethyl acrylamide,sodium alginate and MXene was prepared.The hydrogel has high tensile properties（tensile strain up to 1910%）,good conductivity（conductivity 0.28 S/m）and high sensitivity（GF=3.58）.The hydrogel is assembled into a wearable sensor,which can detect human movement,including large deformation（knee bending,wristbending）and micro deformation（throat vibration）,and demonstrate lasting stability.This work is expected to be applied in human-computer interaction,health diagnosis and intelligent robot prosthetic devices.