UC Berkeley

Inkjet printing has been actively pursued as a means of realizing integrated electronic devices. To date, the vast majority of work on this topic has centered on the development of inks and process integration, while little research has focused on the details of pattern generation.

In this work, we first examine inkjet-printed conductive lines. We show several different printed-line morphologies and explain the causes of these forms of varying utility. More generally, we develop and demonstrate a methodology to optimize the raster-scan printing of patterned, two-dimensional films. We show that any fixed line spacing can not maintain the constant perimeter contact angle necessary for arbitrary patterned footprints. We propose and demonstrate a printing algorithm that adjusts line spacing to print optimal features.

Our work analyzing patterned drops reveals that drop contact angle is a function of position and shape. Numerical solutions to the Young-Laplace equation enable us to predict the sharpest corners possible in a rectangular bead with a given wetting behavior. We verify our computational results with printed rectangles on substrates with variable wetting. Finally, we motivate future research directions including general solutions to a patterned drop's surface in any corner and the behavior of line junctions and other concave corners of printed lines.