| The function of shading and warmth of traditional fabrics cannot meet the urgent demandfor smart clothing in modern society.Conductive fabrics have the advantages of good electrical conductivity,inherent flexibility,air permeability and easy integration,and have great application potential in the field of wearable fabric-based strain sensors.Among them,it is an effective way to realize conductive fabrics by combining conductive materials such as conductive polymers,metal based nanomaterials and carbon based nanomaterials with commercial fabrics.Then,a series of fabric-based strain sensors with different functions have been developed.However,there is still much room for improvement in fabric-based strain sensors with high conductivity,excellent sensing performance and high stability.In this dissertation,the surface of knitted nylon/spandex fabrics was modified with polydopamine(PDA)to improve the interfacial bonding strength,and the zero-dimensional silver nanoparticles(Ag NPs)and one-dimensional carbon nanotubes(CNT)were introduced by simple and efficient electroless plating and spraying method.The composite conductive fabrics with alternating conductive layers of Ag NPs and CNT were prepared by optimizing the process parameters.The fabric-based strain sensor with high conductivity,excellent sensing performance and high stability was realized,and the application potential of the sensor in human motion monitoring was explored.The research contents of this paper are as follows:(1)First,PDA was used for surface treatment of the fabrics to bring active groups toenhance the binding force between the conductive materials and the fabrics.Subsequently,silver trifluoroacetate(STA)and L-ascorbic acid(LAA)were used as precursor and reductant respectively to construct conductive fabrics based on Ag NPs by electroless silver plating.Finally,polydimethylsiloxane(PDMS)was coated on the outer layer of conductive fabrics to give hydrophobicity and stability.By adjusting the number of silver plating,the Ag NPs content on the fabric surface was adjusted,and the conductive fabrics with different performance and uses were obtained.When the number of silver plating was 2,the strain range of PDMS/Ag-2/PDA/Fabric-based sensor was 0-30%and the average sensitivity was 21.4.In addition,the sensor had a fast response time(188 ms)and a low latency(10.1%).When the number of silver plating was 5,the Ag NPs conductive network on the fabric surface was stronger,the maximum tensile strain of PDMS/Ag-5/PDA/Fabric reached 50%,and the surface resistance was as low as 1.9?sq-1.At the same time,the resistance of PDMS/Ag-5/PDA/Fabric increased from 3.1?to 3.6?when stretched by 30%strain,and showed good tensile conductivity stability.Finally,the conductive fabrics were used to monitor human motion signals and connect the flexible stretchable conductor of the circuit respectively.(2)The carbon nanotubes were introduced into the surface of the silver-coated fabrics byspraying to construct composite conductive fabrics with alternating conductive layers of Ag NPs and CNT,which were hydrophobically modified with PDMS to obtain PDMS/Ag/CNT/Ag/PDA/Fabric-based sensor.The high aspect ratio CNT can act as a"bridge"between the Ag NPs,connecting the cracks generated by the conductive network of the brittle Ag NPs during stretching,and increasing the strain range of the sensor while maintaining a high sensitivity.Therefore,the sensor exhibited good electrical conductivity and sensing performance with a surface resistance of about 8?sq-1,a strain range of 0-50%,and an average sensitivity of 43.In addition,the sensor also had good hydrophobicity(contact angle of 141°),bending resistance(resistance increases by only 1.8%after 200 times of 180°bending)and wear resistance(resistance increases by only 4.7%after 100 times of rubbing).Finally,the sensor can realize the monitoring of human motion(wrist bending,swallowing,etc.)signals. |
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