Preparation And Properties Of Nerve Agent Visualization Sensing Composite Conductive Yarn

In the past few decades,research in the field of wearable sensors and biosensors for realtime monitoring of biological or chemical signals has emerged,and the application of wearable sensors to nerve agent sensing is considered promising and has received significant attention,but most of these studies are currently based on electrochemical sensing technology,which has the disadvantages of incompatibility with fabric substrates,outdated energy supply methods,and low detection limits(most of them do not reach the ppb level).The application in wearable nerve agent sensing is still limited fluorescence sensing of nerve agents is an ideal nerve agent sensing technique with the advantages of low cost,fast response time and sensitive detection,but its combination with wearable technology for nerve agent detection has received less attention.In view of this,this thesis uses a fiber-yarn-fabric design path to integrate nerve agent fluorescence visualization detection and wearable technology using NFC fabric antenna technology as a bridge to achieve fluorescence visualization detection of nerve agents on fabric while monitoring the wearer’s physiological signals in real time.The full paper is as follows:(1)A one-step physical blend of polymer and fluorescent probe molecules was used to prepare an electrostatic spinning precursor solution using a conjugated electrostatic spinning process.The complete coating of fluorescent nanofibers on PA-Ag core conductive yarns and the continuous industrial-scale preparation of conductive yarns for nerve agent visualization sensing were achieved under the synergistic effect of three fields: electrostatic field,eddy current field and velocity field.The nanofibers are uniformly distributed in the outer layer of the yarn loaded with fluorescent probe molecular material.The yarn has a contact angle greater than 100°,an elongation at break of 37.2% and a change in resistance of less than 25% before and after coating with fluorescent nanofibers,offering good potential for application.(2)The nerve agent visualization sensing composite conductive yarn was prepared into a visualization sensing fabric by plain weave process to make it have good wearable effect and at the same time,the fluorescence mechanism and fluorescence performance were studied on the basis of the fabric,and it was found that the fluorescence change of the nerve agent visualization sensing fabric came from the intramolecular charge transfer(TICT)caused by the competition between hydrogen atoms on different nitrogen inside the molecule.We prepared the nerve agent visualization sensing fabric with excellent fluorescence gas detection performance,such as immediate and efficient fluorescence detection ability,after exposure to DCP gas fabric fluorescence intensity instant change and more than 3.5 times;excellent fluorescence detection specificity,to DEPC,DEP,TEP and other organophosphorus compounds with good antiinterference ability;very low fluorescence detection concentration lower limit,the actual measurement The lower limit of fluorescence detection of visual sensing fabric can reach 6.08ppb(lower than the IDLH level of 7.0 ppb).(3)Taking the fiber-yarn-fabric design path a step further,the NFC fabric antenna technology is used as a bridge to visualize the conductivity of the nerve agent sensing composite conductive yarn and prepare the composite conductive yarn into an NFC fabric coil through an industrial computer sewing machine.The coil is connected to an NFC chip and a physiological signal sensor.When the NFC reader or mobile phone is close to the coil,under the action of electromagnetic field coupling,the coil generates induction current,which drives the chip and sensor to work and transmits the wearer’s physiological signal to the mobile phone APP terminal wirelessly in real time.The signal transmission performance of the coil remains unchanged after3000 bending and twisting tests respectively,indicating that the antenna has good mechanical cycling stability and can be fully adapted to the inevitable mechanical bending situations encountered in wearable and application scenarios.