Control of Direct Written Ink Droplets Using Electrowetting

Abstract

Here, we investigate the feasibility and effectiveness of electrowetting in the motion control of droplets of different liquids, which are widely used as inks in direct writing (DW)-based three-dimensional (3D) printing processes for various applications. To control the movement of DW ink droplets on dielectric substrates, the electrodes were embedded in the substrate. It is demonstrated that droplets of pure liquid inks, aqueous polymer solution inks, and carbon fiber suspension inks can be moved on multi-angled surfaces. Also, experimental results reveal that droplets of a commercial hydrogel, agar−agar, alginate, xanthan gum, and gum arabic can be moved by electrowetting. Droplets of sizes 200 μm−3 mm were manipulated and moved by the electric field on different dielectric substrates accurately and repeatedly. Effective electrowetting-based control and movement of droplets were observed on horizontal, vertical, and even inverted substrates. These findings imply the feasibility and potential application of electrowetting as a flexible, rapid, and new method for ink droplet control in 3D printing processes.

Electrohydrodynamics of dielectric droplet collision on different wettability surfaces

“…Another method of supressing droplet rebound is by distorting the symmetry of the droplet shape by application of electric field [8,9]. Electrohydrodynamics (EHD) based control and actuation has been shown to be effective in achieving better performance of droplet-based lab-on-a-chip devices [10][11], atomization processes [12][13], EHD inkjet printing and electronic cooling [14][15].…”

Stimuli-responsive surfaces for switchable wettability and adhesion

“…The displacement of the oil droplet was affected by the distance between the droplet and the conductive hole. Furthermore, Plog et al [91] studied the electric responsive movement of ink droplets which have diverse chemical composition and droplet size on the Cu electrode-embedded substrate (figure 7d). They realized the accurate motion control of commercially pure-liquid, carbon fibre suspension and polymer solution ink droplet in 200 µm-3 mm diameters by adjusting the applied voltage.…”

“…(d ) On Cu electrode-embedded substrate, electric responsive fast moving of large ink drop. Adapted from[91]. Copyright © 2019, American Chemical Society.…”

Virtual Stencil for Patterning and Modeling in a Quantitative Volume Using EWOD and DEP Devices for Microfluidics

“…In 2015, Banerjee et al proposed a programmable microfluidic system that integrates a continuous fluid and digital microfluidics [ 35 ]. Digital microfluidic technology through electrowetting on dielectric (EWOD) systems is widely used, such as in a laboratory on a chip [ 36 , 37 , 38 , 39 ]. In 2014, Liu proposed a simple and accurate image-based technique to measure a droplet volume to generate nanometer droplets from continuous electrowetting microchannels [ 40 ].…”