Preparation of aqueous Ag Ink with long-term dispersion stability and its inkjet printing for fabricating conductive tracks on a polyimide film

We synthesized silver nanoparticles via chemical reduction method in aqueous medium and poly(acrylic acid) sodium salt (PAA), a kind of anionic polyelectrolyte, was used as a capping agent as well as a dispersant. Owing to the electrosteric repulsion characteristic of PAA, the prepared aqueous Ag ink exhibited a remarkable dispersion stability, which was confirmed by sedimentation test, zeta-potential measurement, and rheological analysis. We fabricated narrow conductive features onto the polyimide substrate using ink-jet printing method and demonstrated the influence of substrate temperature on the morphology of printed patterns. After annealing at $250°C$⁠, the resistivity of the Ag pattern with a linewidth of $60μm$ was $4μΩcm$⁠.