The Effect of Substrate on Continuous Electrohydrodynamic Printing

Abstract

In this paper, the behavior of ejected jet is studied at three different substrates (conductive, semiconductor and dielectric) in continuous electrohydrodynamic inkjet printing mode. Because the polarization charges will accumulate at the surface of the substrate in a short nozzle-to-collector distance, one can observe that the different flight behavior in the space. Results show that the substrate has little effect on the threshold voltage and the relaxation time of the substrate can be used to indicate the behavior of the jet. When the lifetime of the jet is larger than the relaxation time of the substrate, the jet can be deposited on the substrate regularly. Based on this guideline, a designed parallel lines and grid pattern are fabricated with several micrometers on a silicon substrate. These show that the designed pattern could be fabricated in a controllable jet. In the future, this method is able to be utilized to fabricate the mirco/nano-devices.

Control of UV-Curing Ink Splashing and Line Quality during DC-Pulse-Modulated Electrohydrodynamic Printing for Textile-Based Electronics

“…For a good conductor like copper, the τ is of the order of 10 −19 s, whereas for a pure insulator, it becomes infinite. Bu et al 26 studied the formation process of the jet on the insulating, dielectric, and conductive substrate, and the relaxation time of the substrate and the lifetime of the jet were proposed as the characteristics to evaluate the jet behavior. When the jet lifetime is higher than the charge relaxation time of the substrate, the substrate charge can dissipate quickly and the jet can straightly deposit on the substrate.…”

“…When the substrate is placed in an electric field, electric charges will accumulate on the substrate surface in a short nozzle-to-collector printing distance. The surface charge density can be evaluated by σ = | ε 0 false( E normaln normalo − β E normaln normali false) | where σ is the surface charge density, E n o and E n i are the relative outer and inner normal electric fields, β is the relative permittivity, and ε 0 is the absolute permittivity. As all the process conditions are the same, the surface charge density is affected by the substrate material.…”

“…Changing the electrical properties of printing substrates is another method to dissipate the residual charges. Bu et al 26 found that when printing on a conductive substrate, in which the charge relaxation time of the substrate is lower than the jet lifetime, the substrate charge can quickly dissipate and uniform straight lines will form. To obtain the well-deposited pattern, Luo et al 27 utilized the penetration of solvents on the porous paper to transfer the charges to the ground.…”

Mechanisms, Capabilities, and Applications of High‐Resolution Electrohydrodynamic Jet Printing

“…In particular, the cumulative build‐up of charge can be significant on insulating substrates, where it can distort the electric field and alter the trajectories of the droplets. These effects result in variations in the size and position of the droplets . While this phenomenon may provide a means to control the positions of droplets on surfaces, this phenomenon is typically unwanted in a printing process.…”

“…These effects result in variations in the size and position of the droplets. [ 53,56 ] While this phenomenon may provide a means [ 57 ] to control the positions of droplets on surfaces, this phenomenon is typically unwanted in a printing process. Methods for dissipating these charges, or eliminating them entirely, range from the use of conductive substrates or substrate supports, ac fi elds for printing, or means to externally introduce counterions.…”