Preparation Of Strain/humidity Sensor Composed By Flexible Core-sheath Yarn And Its Application In Smart Wearable Clothing

Flexible sensors can be used to monitor information such as strain,humidity,temperature and physiological signals of the human body,which can be widely used in intelligent transportation,sports fashion,intelligent home and health care and other fields.However,the combination of flexible sensors and smart wearable clothing mostly involves placing the sensors on the fabric,rather than combining them.In this paper,a polyester/polyurethane core-sheath yarn,and two-dimensional conductive materials graphene and MXene were used as the substrate for the sensor,then study the sensing properties of conductive core-sheath yarn and textile composed of conductive core-sheath yarn on and their applications in the field of intelligent wearable clothing.The main research contents are as follows:First,in order to improve the sensor's sensing performance and durability,a lowcost spring-shaped high-elastic core-sheath yarn was selected as the flexible substrate,and graphene was used as the conductive material for the sensor.A graphene-based strain sensor for the core-spun yarn was prepared by impregnation and core absorption The core-sheath yarn not noly has high elasticity of polyurethane filament as core,but also the durability,corrosion resistance and deformation during stretching,of polyester filament as sheath,which makes it have excellent sensing performance.Therefore,it is an excellent substrate for strain sensing yarn.The sensor exhibits high elasticity(> 300%),fast response time(120ms),high strain range(0.3-100%),and excellent durability(> 10,000 times).Second,In order to realize the combination of a variety of sensor performance,a high-elastic conductive yarn based on the new two-dimensional conductive material MXene and the core-sheath yarn can be used not only as strain sensor but also as humidity sensor due to the special chemical structure of MXene.In addition to the advantages of high elasticity and high strength,this core-sheath yarn has a larger specific surface area and a larger contact area with air than the common yarn of the same fineness.Therefore,it is an excellent substrate for humidity sensor.In addition to the excellent Gauge Factor(0.67),fast response time(120ms),high strain range(0.3-120%),excellent durability(>10000 times),the sensor can also monitor humidity changes in a high range(30-100%RH).Thirdly,In order to combine the two conductive sensor yarns mentioned above with smart wearable clothing,the two kinds of prepared conductive yarn sensors are knitted into the fabric with different patterns through the knitting machine,and a capacitive strain sensor is also prepared by the knitted fabric sensor.The prepared yarn sensor and knitted fabric sensor were connected to the human body to test a variety of physiological signals,such as pulse,vocal cord vibration,joint bending,etc.Therefore,the flexible textile structure strain/humidity sensor designed by us can be directly knitted into smart clothing,which has the advantages of portability and durability,and has a broad application prospect in monitoring the daily physiological activities of patients,children and the elderly.