Inkjet printed lines on a homogeneous solid substrate are studied under the condition that ink evaporation is not negligible and the contact angle exhibits hysteresis with non-zero receding contact angle (NRCA). A new family of line instability is discovered, featured by formation of agglomerations within a line. The agglomeration is explained by a flow that consistently drives a bead on the substrate towards fresh deposited drops due to concentration-induced surface tension gradient. Morphologies of lines printed with multiple layers are also investigated for the purpose of conductive trace fabrication. A non-uniform morphology is observed across a multi-layer line when the line is printed unidirectionally at a low jetting frequency. This non-uniformity is explained by considering interaction between deposited drops and bulk layer. Optimized multiple-pass printing is developed to produce a uniform line morphology while offering excellent printing efficiency and electrical conductivity.
Chenchao Shou, Patrick McCarthy, George T. C. Chiu, Timothy S. Fisher, "A Study of Inkjet Printed Line Morphology Using Volatile Ink with Non-zero Receding Contact Angle for Conductive Trace Fabrication" in Proc. IS&T Int'l Conf. on Digital Printing Technologies and Digital Fabrication (NIP29), 2013, pp 384 - 389, https://doi.org/10.2352/ISSN.2169-4451.2013.29.1.art00031_2