Modification of surface properties for industrial ink-jet printing

The characteristics of silver inkjet printing were intensively investigated under control of surface energy and substrate temperature. A fluorocarbon (FC) film was spincoated on a polyimide (PI) substrate to obtain a hydrophobic surface, and an ultraviolet (UV)/ozone (O-3) treatment was performed to control surface wettability of the FC film surface. To characterize the surface changes, we performed measurements of the static and dynamic contact angles and calculated surface energy by Wu's harmonic mean model. In silver inkjet printing, the hydrophobic FC film could reduce the diameter of the printed droplets. Merging of deposited droplets was observed when the substrate was kept at room temperature. Substrate heating was effective in preventing the merging phenomenon among the deposited droplets, and in reducing the width of printed lines. The merging phenomenon of deposited droplets was prevented also by increasing the UV/O-3 treatment time.