Optimization of Experimental Parameters To Determine the Jetting Regimes in Electrohydrodynamic Printing

Abstract

The harmony of ink and printing method is of importance in producing on-demand droplets and jets of ink. Many factors including the material properties, the processing conditions, and the nozzle geometry affect the printing quality. In electrohydrodynamic (EHD) printing where droplets or jets are generated by the electrostatic force, the physical as well as the electrical properties of the fluid should be taken into account to achieve the desired performance. In this study, a systematic approach was suggested for finding the processing windows of the EHD printing. Six dimensionless parameters were organized and applied to the printing system of ethanol/terpineol mixtures. On the basis of the correlation of the dimensionless voltage and the charge relaxation length, the jet diameter of cone-jet mode was characterized, and the semicone angle was compared with the theoretical Taylor angle. In addition, the ratio of electric normal force and electric tangential force on the charged surface of the Taylor cone was recommended as a parameter that determines the degree of cone-jet stability. The cone-jet became more stable as this ratio got smaller. This approach was a systematic and effective way of obtaining the Taylor cone of the cone-jet mode and evaluating the jetting stability. The control of the inks with optimized experimental parameters by this method will improve the jetting performance in EHD inkjet printing.

Influence of electrohydrodynamic jetting parameters on the morphology of PCL scaffolds

“…As the PCL has a low melting point, the viscosity of the polymer solution decreases rapidly with the increase of temperature, thus lowering the viscoelastic force acting on the Taylor cone during EHD-jetting. Moreover, during the printing process, the polymer chain tends to orient along forced direction and solidifies on substrate upon evaporation of the solvent in which the temperature and humidity show significant influence on the solvent evaporation rate [29][30] . Therefore, the temperature variation directly affects the EHD jetting process and the morphology of the scaffold.…”

Classification of electrohydrodynamic spraying modes of water in air at atmospheric pressure

“…This technique is capable of generating monodisperse droplets, and affords excellent control over droplet size and the properties of the jet. EHD spraying has been applied in various fields (Fenn, Mann, Meng, Wong, and Whitehouse, 1989;Ganan-Calvo, Lopez-Herrera, & RiescoChueca, 2006;Lee, Jin, Dang, Choi, & Ahn, 2013;Loscertales et al, 2002) and a number of theoretical and experimental studies have investigated the mechanism involved in EHD spraying, since its first observation by Zeleny (Fernandez de la Mora, 2007;Ganan-Calvo, 1997;Taylor, 1964;Zeleny, 1917).…”

Nanoparticle assembly enabled by EHD-printed monolayers

“…These monolayers were quite stable across large scales on the surface (Figure 6a). Some additional, sub-100 nm bands of APTES were observed running parallel to these lines, and were probably the result of multiple jets forming from the nozzle head 28 . The resolution also shows some hysteresis in size, due to the Figure 4 Process for electrohydrodynamic (EHD) printing of functional monolayers.…”