Effect of micro surface structure on printing

Abstract

Experimental investigations of the effect of micro surface structure on printing for printed electronics have been carried out. In our experiments, photolithography MEMS fabrication is used to make SU-8 molder which has micro structures on the surface, and PDMS micro structure is by PDMS molding method. In the aspect of printed electronics, I use silver conductive ink as the ink. To enhance printing result, control of surface energy between ink and substrate is needed. We investigate possibilities of changing surface energy by using various surface structures. In this paper, I will present the results about surface energy variation on two kind of microstructure. The one is groove microstructure and another is pillar microstructure. Next, the difference of droplet shape between on the microstructure surface and on flat is observed. The substrate which has micro structures on surface can be guided for electronic circuit patterns. This effect is expected to help to make the edge of line pattern fine and straight. Last, the microstructure is applied to real printing experiment by screen printing and offset printing. I measured the electrical conductivity of printed line patterns and observed the geometry of printed result by microscope.