Effects of pulse voltage on inkjet printing of a silver nanopowder suspension

Inkjet printing of a liquid suspension prepared by dispersing silver powders of size around 4 nm in deionized (DI) water at 30 wt% was investigated in this study. By comparing with the results of pure DI water, the effects of nanoparticles on droplet formation between the nozzle and the substrate were also studied. A bipolar pulse waveform was employed in driving the piezoelectric printhead with pulse voltage set as the primary variable of this study. Observations showed that a higher driving pulse voltage was required for the silver suspension to form droplets than DI water. The liquid column broke up at the nozzle orifice for DI water while the silver suspension broke up further away below the nozzle office. It was also observed that the droplet size of the silver suspension was smaller than that of DI water. For the silver suspension the liquid column formed was thinner and longer and the pinch-off time of the liquid column to form droplets was also longer. However, the characteristic adjustment time for droplet recombination was shorter for the silver suspension than for DI water.