Construction Of Textile-Based Touchless/Tactile Bimodal Sensor And Research On Wearable Application

Flexible wearable electronic devices with multiple functions and suitable for human body have attracted extensive research interest in recent years with the rapid development of artificial intelligence.Capacitive sensor has the advantages of temperature insensitive,low power consumption,fast dynamic response and simple structure design.It has broad application prospects in human-machine interface,electronic skin,real-time health monitoring,soft robots.Currently,many flexible substrates have been studied to fabricate flexible wearable sensors,such as polymer films,sponges,textiles,etc.Textile-based sensors can have both wearable comfort performance and multi-functional sensing performance,and become an important research branch in the intelligent wearable sensors field.However,there is little research on the multimodal sensing performance of textile-based sensors,especially in touchless/touch multimodal sensing.Touchless sensing realizes the interaction with the surrounding environment through non-contact mode,which is of great significance for COVID-19 to spread the situation.Touch sensing gives the robot“tactile”perception,which can realize the function of simulating human skin.It has great application potential in human-computer interaction.Therefore,capacitive sensors based on textile materials still have great potential in touchless/touch multimodal sensing performance.In this paper,nickel-plated woven fabric is used as flexible electrode,and single-component silicone rubber,knitted fabric and spacer fabric are used as dielectric layer materials to select touchless/touch multimode textile-based capacitive sensors with better performance.The main research contents are as follows:（1）To ensure the good flexibility of the sensing equipment,nickel-plating fabric and single component silicone rubber were selected as electrodes and dielectric layers to fabricate touchless/tactile bimodal sensors.Silicone rubber and nickel-plating fabric have good flexibility,deformability and mechanical properties,and the sensors prepared by them maintain the flexibility.The experimental results show that the sensor has good pressure sensing performance,with sensitivity of 0.0014 k Pa^-1,durability higher than 10000 cycles of loading/unloading,and light pressure detection limit as low as 5.88 Pa.In addition,the sensor also has good touchless detection performance（the detection range is 0-3.0 cm,the maximum relative capacitance variation is-7%）.Moreover,nickel-plating woven fabric has good electrical conductivity and no damage in repeated compression experiments,which has great potential in the preparation of flexible electrodes.（2）To making the flexible sensor have good wearable comfort,this chapter uses nickel-plating fabric as electrode and weft knitted fabric as dielectric layer to construct knitted touchless/tactile sensor.The nickel-plated woven fabric electrode layer and the intermediate knitted fabric dielectric layer have good air permeability and moisture permeability,making the sensor comfortable to wear（such as lightness,breathable）while providing both tactile(0.00246 k Pa^-1)and touchless(0.022 cm^-1)signal sensing functions.The experimental results show that the permeability and moisture permeability of the sensor are 168.20 g/m²h and537.86 mm/s respectively,and the touchless and pressure bimodal signals can be continuously monitored in real time.The prepared sensor array has good spatial resolution and can accurately perceive and track the positions of fingers and heavy objects.It has broad application potential in human-computer interaction,soft robots,and electronic skin.（3）To improve the sensing performance of textile-based sensors,spacer weft fabric was used as the dielectric layer to prepare flexible wearable sensors.Spacer fabric is composed of two layers of weft knitted fabric and support yarn.It has a stable three-dimensional structure and features of compression stability,low cost and wearing comfort.The spacer fabric treated with graphene dispersion further improved the pressure sensitivity of the sensor(0.33 k Pa^-1).Moreover,this sensor shows excellent touchless sensing(0.069 cm^-1),air permeability（448.77mm/s）and moisture permeability（147.11 g/（m²·h））,which has unique advantages in the field of flexible wearable.（4）To prove the application potential of textile-based sensors in the wearable field,the three-dimensional spacer fabric-based sensors are first integrated into the training clothing,which can accurately monitor the boxing speed and pressure,and realize the continuous intelligent digitization of tactile and tactile signals on flexible wearable clothing.It has a practical application prospect in the intelligent digitization of human combat training.In addition,according to the excellent non-contact performance of the sensor,a non-contact early-warning system is prepared,which has important value in protecting personal safety and reducing cross-infection.