High-resolution ac-pulse modulated electrohydrodynamic jet printing on highly insulating substrates

Abstract

This paper presents a new high-resolution ac-pulse modulated electrohydrodynamic (EHD)-jet printing technology on highly insulating substrates for drop-on-demand fabrication of electrical features and interconnects using silver nanoink. In traditional EHD-jet printing, the remained charge of the printed droplets changes the electrostatic field distribution and interrupts the follow-on printing behavior, especially for highly insulating substrates which have slow charge decay rates. The residue charge makes the control of EHD-jet printing very challenging for high-resolution continuous features. In this paper, by using modulated ac-pulsed voltage, the EHD-jet printing process switches the charge polarity of the consequent droplets to neutralize the charge on the substrate. The effect of the residue charge is minimized, which enables high-resolution printing of continuous patterns. Moreover, by modulating the pulse frequency, voltage, and duration, the EHD-jet printing behavior can be controlled with respect to printing speed/frequency and droplet size. Printing frequency is directly controlled by the pulse frequency, and the droplet dimension is controlled by the voltage and the duration of the pulse. We demonstrated that ac-pulse modulated EHD-jet printing can overcome the long-predicated charge accumulation problem on highly insulating substrates, and potentially be applied to many flexible electronics applications.

Nanoparticle assembly enabled by EHD-printed monolayers

“…need to maintain a stable electric field, which would require a closed feedback loop and better control of charge build up in the printed ink 29 .…”

“…Although the stability of this printing resolution could not be maintained across a larger scale, it is clear from these results that EHD printing is capable of writing templates of functional APTES with nanoscale resolution. More stable printing solutions are likely to be achieved through controlled printing of droplets using pulsed deposition 29 .…”

Thin film zinc oxide gas sensor fabricated using near-field electrospray

“…Recent attempts to fabricate all printed devices have focused on Electrohydrodynamic (EHD) printing, which involves an electrostatic field to stretch a polymer solution into fine jet. 9,10 The outer stretching force, caused by the electric field, contributes to the decrease in the diameter of the fine jet. During EHD, the diameter of the charged jet is smaller than the inner diameter of the nozzle.…”

Development and Modeling of Melt Electrohydrodynamic-Jet Printing of Phase-Change Inks for High-Resolution Additive Manufacturing

“…Currently, most of the EHD printing applications focus on the fabrication in two dimensions (2D), such as patterns [20,21,25,26], with only some initial investigation toward 3D fabrication [18,19]. Similar to conventional 3D printing, drop-on-demand EHD printing with phase-change inks in pulsating mode produces a single droplet at a time, which provides promising potential for 3D printing with microscale resolution.…”