Construction Of A Knitted Fabric Flexible Strain Sensor And Its Bidirectional Sensing Performance In Tension/compression

With the increasing popularity of the wearable electronic devices,through to the human body in full interaction of textiles with sensitive material made of the"digital textile"integration,implementation in between the body and the external environment of power conversion,heat exchange,temperature and heat transfer,light absorption and emission physical indexes such as signal recognition and digital transmission,It is an important research topic for the development of traditional textile to intelligence and information technology.Among them,the strain sensor based on the unique structural characteristics of textiles has more practical application prospects,such as the monitoring of heartbeat,pulse,respiration,pronunciation,body movement and other physiological and motor indicators.This paper,by using a unique 2×2 interlock knitted fabric structure,can be large-scale production of dip coating method is used to base material with superior power to learn for a performance of graphene consolidation,constructed a tensile/compression bidirectional sensing properties of strain sensor,through the in tension and compression state structure and sensing properties of the findings.The results show that it has high sensitivity(25.32 kPa^-1at 3 kPa pressure,gauge factor 32.62 at 25%tensile strain),high ductility(?>25%)and dynamic stability(signal drift<6%after 300 cycles).Taking advantage of the above performance advantages,this paper designs a wireless Bluetooth signal acquisition and transmission system for real-time monitoring of human body movements and walking movements.Specific research contents include:First of all,for the preparation of the flexible strain sensor,choose graphene as a conductive material,2×2 interlock knitted fabric as the sensor substrate,sodium alginate solution for graphene of dispersant,stabilizer,and combined with the material,by high efficiency,simple and can be mass production of coating method and the hot pressing process,the graphene/sodium alginate composite with knitted fabric,mixture of CaCl₂solution by dipping form calcium alginate gel film,with tensile/compression bidirectional flexible strain sensor,the sensing properties of the knitted fabric structure and analyzes the graphene,a combination of calcium alginate and knitted fabric performance.Then,this paper introduces the preparation of the knitted fabric structure tensile/compression bidirectional flexible strain sensor sensing mechanism of the sensor performance,by building a model of equivalent resistance analysis,explain the sensor relative resistance in the process of strain and the reason of the change of flexible strain sensor on mechanical properties and two-way sensor performance test and analysis.Finally,the application field of flexible strain sensor is expanded according to its bidirectional tension/compression sensing performance.The flexible strain sensor prepared in the experiment can realize the monitoring of human activities such as changes in human joints,muscle changes and simulated walking.In addition,the micro Bluetooth module is connected to the sensor to collect motion parameters and transmit them to electronic devices such as mobile phones,thus realizing the visualization of data.The research in this paper not only proves the feasibility and practicability of using textile structure to construct strain sensor,but also realizes the tension/compression bidirectional sensing performance by using the unique 2×2 double rib knitted fabric structure,which provides some new ideas for the design and application of strain sensor.