Preparation Of Biomass-based Fabric Electrodes And Their Applications

With the development of electronic products,wearable electronic products have attracted more and more attention.Wearable sensors,wearable energy capture and wearable energy storage are the focus of research.The key material of wearable electronics is fabric electrode with excellent electrical conductivity and washing stability.The substrate of fabric electrode is usually made of fabric,and the fabric electrode is prepared by carrying conductive layer.The synthetic polymer fiber itself does not contain functional groups.Biomass-based fiber contains a large number of functional groups and this will help to improve the stability of the conductive layer.Therefore,it is an important research direction to study the preparation of fabric electrode with excellent electrical conductivity and washing resistance using biomass fiber as matrix material.In this paper,a fabric electrode with good electrical conductivity and environmental stability was successfully prepared in situ reduction and by coating,with silver metal as conductive component and chitosan and cellulose fiber fabric as matrix.The surface morphology,crystallinity,thermal stability,surface hydrophobicity and other properties of silver-plated fabrics were characterized.The fabric electrode was used to capture the ECG during human motion.1.The fabric electrode based on chitosan fiber fabric was prepared by Tollens synthesis method.[Ag（NH₃）₂]⁺was reduced by glucose.A uniform layer of AgNPs were loaded on the surface of chitosan fiber.The experimental results show that:AgNPs on the surface of the fiber show a metal state and form a uniform silver layer.The silver layer is compact and the surface of chitosan fiber is completely covered with AgNPs.The surface of AgNPs-plated fabric is hydrophobic.When silver plating amount is 2 g/g,the square resistance of fabric electrode is 0.12Ω/sq.After 60 times washing,the square resistance increases to 4.91Ω/sq.Compared with pure chitosan fabric,the thermal stability of fabric electrode is improved,but the breaking strength and elongation decreased.2.Chitosan fiber fabric was used as matrix material and a layer of AgNPs was loaded on the surface of chitosan fiber by using the reductivity of chitosan itself without any reducing agent.Then a layer of AgNWs was coated to improve the stability of the conductive silver layer and the fabric electrode was prepared by using the interaction force between metals.The experimental results show that:Chitosan has a strong reduction property.After in situ reduction,a large number of dense and uniform AgNPs with 50nm size were loaded on the surface,and the silver content on the surface increases with the increase of AgNO₃concentration.After oxidation with AgNO₃,the crystallinity of chitosan decreased.Repeated dip coating can improve the AgNWs contents on chitosan fabric surface,thereby increasing the conductivity of the fabric.The AgNWs contents adsorbed on the surface of fabric are ralated with the AgNPs on the surface of fabric.At least three times dipping is needed to get fabric electrode with resistance less than 1Ω/sq.Fabric electrode has good thermal stability.With the increase of silver content,the antibacterial activity of fabric electrode also increased.3.Woven cellulose fabric with weaker swelling was used as matrix material.On the basis of the second chapter,AgNWs were prepared by polyol method,and then the mixture of PVA and AgNWs were coated on the surface of cellulose fabric.GA was used as crosslinking agent to decrease the hydrophilicity of PVA on silver-plated fabric,thus improving the washing stability of conductive silver layer.The prepared fabric electrode was used to capture the ECG during human motion.The experimental results show that:AgNWs were successfully prepared by polyol method.AgNWs and PVA were intertwined together on the surface of cellulose fiber fabric and form a uniform conductive layer.The prepared AgNWs have preferential orientation of（111）plane.The fabric electrode has good thermal stability.The square resistance of fabric electrode is 0.4Ω/sq.The antibacterial efficiency of fabric electrode is over 99.9%.The prepared fabric electrode was embedded in intelligent clothing and used to capture the ECG of human motion.The obtained ECG is normal and can be used to measure the heart rate of human body.With the increase of the speed of movement,the heart rate increases,the amplitude of the waveform also slightly increase,and the number of clutter increases.The resistance of the fabric electrode increased to 0.68Ω/sq,and the QRS and T of captured ECG waves of are still visible after 100 hours of washing.