Investigation On Preparation And Application Of Water-based Nanosilver Conductive Ink For Inkjet Printing

Printed electronics is a low-cost, high efficiency way to fabricate circuits andelectronic devices by printing functional materials on substrates. Compared to thescreen printing method, inkjet printing has been paid more attentions because of itsability to precisely deposit materials onto different substrates by one step. As the basicmaterials of conductive ink, several conductive components were studied includingmetallic nanoparticles, conductive polymers and carbon materials. Among these,silver nanoparticle gained significant interest in recent years because it has the highestelectrical conductivity and strong stability. Meanwhile, more attention has been paidto investigate water-based ink due to the outstanding properties of water. Therefore, itis significant to develop water-based nanosilver conductive ink for inkjet printing.Firstly, the concentrated and relatively pure water-based silver colloid wasobtained after separation and washing treatments to the nanosilver colloid. Forpreparation of the conductive ink，some different essential additives were added to theconcentrated silver colloid. Considering the adhesion, stability, viscosity, moisture,surface tension, foaming and conductivity of the prepared ink, we discussed theeffects of different kinds of additives and additive contents on the properties ofconductive ink. The experimental results showed that sodium caboxymethylcellulosewas a good binder and Spredox D-260was an excellent dispersion stabilizer.Meanwhile glycerol had a great influence on moisture of the conductive ink. We alsofound that Surfynol465and BYK-028had an excellent ability to reduce surfacetension and foamability of the conductive ink.Secondly, we studied the printability of different types of substrates (paper,plastic film) to the prepared ink with the silver content of15percent and the effects ofvarious post-treatments on the conductivity of the printed patterns. It was found thatporous high glossy photo paper and polyimide film were good candidates to thesubstrates. The sheet resistance of paper-based conductive pattern would reduce to800mΩ/□when pressure compaction treatment was carried out. Conventional heatingwas recognized as the favorable way to get excellent conductivity to polyimide-basedpattern and the sheet resistance of the pattern decreased to208mΩ/□after heating at350oC for30min. Finally, preliminary application of the prepared conductive ink was also studied.The results showed that the prepared ink had a promising application to manufactureprinted circuit boards and radio frequency identification tag antenna.