Controllable Preparation Of Flexible Graphene/MXene Wearable Sensors With High Sensitivity

Wearable sensors have attracted considerable attention in human motion monitoring,medical care,intelligent robots and human-computer interaction,and the sensor consists of two parts:sensing material and substrate.In this paper,three kinds of flexible sensors fabricated by graphene and MXene as sensing materials are reported.They are the graphene film encapsulated by nylon fabric strain sensor,graphene/carbon nanotubes strain sensor and MXene strain sensor.The graphene film encapsulated by nylon fabric strain sensor based on the high conductivity graphene film which is fabricated by thermal expansion-pressing forming process exhibits the electrical conductivity of 9.09 x 10⁴ s/m,gauge factor of 9.7?strain:0-11.5%?and 48.2?strain:11.5%20%?,the linearity between the rate of the change in resistance and strain of 99.131%and94.924%,hysteretic error with 10.16%.For graphene/carbon nanotube strain sensor made up of graphene platelets/multi-walled carbon nanotubes mixture?30wt.%graphene loading?is fabricated by a spray-method,the optimized ultrasonic time and the ball mill mixing process make the graphene platelets disperse evenly in the multi-walled carbon nanotubes,the sensor exhibits the electrical conductivity of 10⁴S/m,gauge factor of 181.4?strain:0-7.5%?and567.7?strain:7.5%-12%?,the linearity between the rate of the change in resistance and strain of 99.545%and 98.877%,hysteretic error with 8.25%.The MXene strain sensor made of the Ti₃C₂ etching of Ti₃Al C₂is also fabricated by a spray-method,the ultrasonic power is 80W and the ultrasonic time is 40min for the MXene solution,the MXene sensor exhibits the electrical conductivity of 370000S/m,gauge factor of 134.7?strain:0-10%?and 427.7?strain:10%-25%?,the linearity between the rate of the change in resistance and strain of 99.077%and 98.311%,hysteretic error with 7.50%.The three flexible sensors are still avalible after thousands of cycles and they are able to monitor large body deformations,including the bending of fingers,wrists,elbows and knees;micro-deformable behaviors of the human body include blinking,cheek bulging,vocalization,and pulse rate.