Preparation And Characterization Of AgNWs/Water-based Acrylic Resin Conductive Ink

With the rapid development of science and technology,electronic products are developing towards the direction of miniaturization,flexibility and environmental protection.Printing electronic technology is rising gradually.Conductive ink is the key material in the development of this technology.However,there is still some problems for the conductive ink,such as high sintering temperature,poor mechanical properties of ink layer,and the conductivity needs to be improved.It is quite necessary to develop environment friendly conductive inks.In this study,silver nanowires?AgNWs?were used as conductive filler and water-borne acrylic resin as binder to prepare an environmentally friendly water-borne nano-silver-based conductive ink with low sintering temperature,good mechanical properties and good conductivity.AgNWs with high aspect ratio were synthesized by using polyols and solvothermal method,silver nitrate as silver source,ethylene glycol?EG?as reducing agent,polyvinylpyrrolidone?PVP?as growth agent and nickel dichloride hexahydrate?NiCl₂·6H₂O?as control agent.The effects of concentration of NiCl₂·6H₂O,reaction time and PVP/AgNO₃ molar ratio on the preparation of silver nanowires were discussed.UV-Vis-NIR spectra,SEM,XRD and Raman spectra of the silver nanowires were analyzed.The results showed that the optimum reaction conditions for preparing silver nanowires were as follows:the concentration of NiCl₂·6H₂O was 200?mol/L,the reaction time was 10 h,and the molar ratio of PVP to AgNO₃ was 2:1.At this time,silver nanowires were well dispersed,with diameters ranging from 25 to 35 nm,and the aspect ratio was up to 1000.A water-based ink was prepared by mixing waterborne acrylic resin,waterborne acrylic emulsion,deionized water,defoamer and dispersant according to a mass ratio of 6/18/1/2.A certain amount of AgNWs/PVP composite was added to water-based ink,and a certain amount of water and ethanol were used as solvent.After grinding for a period of time,AgNWs/water-borne acrylic conductive ink was obtained.The influence of AgNWs content,water-borne acrylic resin ink content,grinding time,sintering temperature and sintering time on the performance of conductive ink,the optimum condition were obtained:when the content of AgNWs was 15%,the content of water-borne acrylic resin ink was 25%,and the others were 60%,the above were ground for 15 minutes and then coated on copper plate paper with OSP wire rod coater.After sintering for 30 seconds of at 150^oC,square resistance as low as 0.176?/sq and the coating surface is flat and level.Conductive ink with the best square resistance obtained at different sintering temperatures was coated on the surface of paper.The changes of square resistance before and after friction resistance test,tear resistance test and bending resistance test were analyzed and discussed.It was found that the conductive ink layer with good friction resistance could be obtained when the conductive ink was sintered at 100^oC,125^oC and 150^oC on the paper base.The conductive ink layer still had good conductivity after 40 tearing or 2000 bending,which proved that water-borne acrylic resin had a positive effect on improving the mechanical properties of conductive ink.