Evaluation of Coatings Applied to Flexible Substrates to Enhance Quality of Ink Jet Printed Silver Nano-Particle Structures

Different types of the commercial surface treatment InkAid have been evaluated as a surface treatment to enhance print quality of silver nano-particle ink structures printed on polyimide and polyethene substrates. Originally these coatings were designed to be applied on substrates for graphical ink jet printing. On the coated polyimide and polyethene substrates lines of different widths have been printed using a Dimatix materials printer together with silver nano-particle ink manufactured by Advanced Nano-Products. The prints have then been evaluated in terms of print quality and resistivity before and after sintering. The results show that the application of these coatings can improve the print quality considerably, making it possible to print lines with a good definition, which is not otherwise possible with this type of ink on this substrate types. It has been found that the semi-gloss coating provides the best results, both in terms of print quality as well as the lowest resistivity. The resistivity on polyethene is 3.5×10^-7 Ωm at best when sintered at 150°C and for polyimide 8.9×10^-8 Ωm sintered at 200°C. This corresponds to a conductivity of about 4.5% and 18% of bulk silver, respectively. It can be concluded that applying such polyvinylpyrrolidone (PVP)-based coatings to polyethene and polyimide will increase the print quality quite substantially, making it possible to print patterns with requirements of smaller line widths and more details than what is possible without coating.