The Basic Research Of Forming Micro-Conductive Lines By Droplet Jet Printing On Fabric Surface

Abstract:In the development of electronic information intelligent textiles,the flexible and integrated preparation of conductive lines connecting the electronic components and fabrics is the premise and foundation of its development.In view of the problems of the complicated process,the limited width of conductive lines,the high cost and the poor flexibility existing in the process of preparation of conductive lines on the fabric surface,this paper proposed a method of forming conductive lines on fabric surface in combination with the droplet injection and the chemical reaction.The printing of conductive lines on fabric substrate was conducted by using the developed pneumatic double nozzle droplet injection system.In the process of printing conductive lines on fabric surface,the direct deposition of conductive lines on fabric surface will occur the phenomenons of liquid infiltration and diffusion because of the porous structure of fabric,which seriously affect the quality of the line,and in the process of printing the conductive lines,process parameters such as substrate speed and deposition sequence will have an impact on the conductivity of formed conductive lines.Based on this,this paper adopted the method of combining theoretical analysis with experimental study,the suitable fabric substrate was optimized by comparing the effects of different treatment methods on the wettability of the fabric and the sedimentary morphology.Then,on the basis of the steady ejection-on-demand of silver nitrate and ascorbic acid solution,the lattice deposition on the fabric substrate was studied,the dimensional uniformity of the spot after the reaction of the two solutions was analyzed.Based on this,depositing conductive lines on the fabric substrate was studied,and the influence of the substrate speed and the deposition sequence on the formed conductive lines was studied.The above studies provide guidance for the subsequent printing of high-quality conductive lines on fabric surface by droplet ejection.The pneumatic double nozzle droplet jet experimental platform was built.According to the principle of pneumatic droplet jet on-demand and the experimental requirement of printing conductive lines by droplet jet,the pneumatic double nozzle droplet jet experiment platform consisted of four modules:droplet ejection device,pulse pressure generating module,image acquisition module and motion control module,which provided device support for subsequent print forming of conductive lines on the surface of the fabric.The effects of different treatment methods on the wettability of the fabric were studied.Based on the actual droplet diffusion area,combining with the fabric structure and fiber type,the better treatment method was optimized and the suitable fabric was determined as the deposited substrate.The wettability of the fabric after modification was evaluated from the three aspects of deposition state,wetting time and diffusion area of droplet.The results showed that the fabric treated with cationic fatty acid amide TF449A,the deposition effect on the surface of woven plain weave cotton with the thread count of 446×338 was best,the contact angle was 78.5°,the wetting time increased from 1.9s to 178.2s,and the droplet diffusion area decreased from 2.13mm² to 0.47mm².The experimental study of fixed-point deposition of silver nitrate and ascorbic acid solution was carried out on the selected fabric substrate.Using the built experiment platform,on the basis of the steady ejection-on-demand of silver nitrate and ascorbic acid,the experimental study of fixed-point deposition reaction of the two solutions was carried out to study the depositional morphology,the size uniformity of the spot,the product and the microstructure after reaction.The results showed that the deposition morphology of the two solutions was better,the uniformity of the points was better,the product after the reaction was Ag,and the silver particles were attached to the surface of the fabric.The experimental and performance study of forming conductive lines with different process parameters was carried out.Based on the principle of droplet jet printing chemical reaction deposition,the study of depositing conductive lines with different substrate speed and deposition sequence was conducted,the influence rule of the two on the microstructure and conductivity of the formed conductive lines was obtained.The study of forming conductive lines with different process parameters showed that,with the increase of velocity of the substrate,the line width first increased and then decreased.The morphology of formed conductive lines was different because of the different deposition sequence.When the deposition sequences were XKXK,XKXKXK and XKKXK?X=silver nitrate,K=ascorbic acid?,the line width was uniform,the boundary of conductive lines was smooth.The microstructure of formed conductive lines showed that,with the increase of velocity of the substrate,the silver particles produced on the fabric surface first increased and then decreased.When the deposition sequences were XKXK,XKXKXK and XKKXK,the number of formed silver particles was more,mainly existed in the form of spherical,flaky,closely connected between the particles,and the particles agglomeration was not obvious.Conductivity study of formed conductive lines showed that,with the increase of velocity of the substrate,the mean and the standard deviation of square resistance of conductive lines first decreased and then increased.When the deposition sequences were XKXK,XKXKXK and XKKXK,the conductivity was better.The validation results of the conductivity of formed conductive lines showed that,The formed conductive lines was electrically conductive,printing forming of conductive lines on the fabric surface was initially realized.