Surfactant-induced delay of leveling of inkjet-printed patterns

Abstract

Due to its flexibility, inkjet printing has become a widespread technique for the non-contact deposition of liquids, solutions and melts on a variety of substrates with a lateral resolution down to about 10 μm. Because the patterns are formed via coalescence of many individual droplets, ripples and undulations can appear in the deposited layers, which gradually disappear if sufficient time before ink solidification is given. In this manuscript, we study this spontaneous leveling process of inkjet printed lines that is driven by surface tension and hydrostatic pressure gradients. We show that the process can be significantly retarded if the ink contains soluble or insoluble surfactants, which are common additives to improve print quality. We present qualitative experiments as well as theoretical and numerical models that allow estimation of the leveling time for arbitrary ripple amplitudes and realistic surfactant properties.

Evaporation of Dilute Sodium Dodecyl Sulfate Droplets on a Hydrophobic Substrate

“…They are commonly used in numerous industries such as food processing, 1 agriculture, 2 pharmaceutical, 3 and inkjet printing. 4 In many of these applications, surfactant-laden droplets are deposited on a substrate, where they are subsequently left to evaporate. 2,4,5 There is a vast amount of literature on the evaporation and dissolution of single- and multicomponent sessile droplets.…”

“…4 In many of these applications, surfactant-laden droplets are deposited on a substrate, where they are subsequently left to evaporate. 2,4,5 There is a vast amount of literature on the evaporation and dissolution of single- and multicomponent sessile droplets. 6,7 Furthermore, the influence of their surface roughness 8−12 and wettability 13,14 on the evaporation process has been extensively investigated in both experimental and theoretical studies.…”

Self-healing dynamics of surfactant coatings on thin viscous films

“…Applications include pulmonary drug delivery [5] and surfactant replacement therapy [6], ocular surfactants and blinking dynamics [7,8], solute transport [9], latex paint drying [10-12], ink-jet printing [13], and secondary oil recovery [14,15]. In each of these processes, amphiphilic surfactant molecules relax the arXiv:1309.3537v2 [physics.flu-dyn] 11 Feb 2014 2 intermolecular bonds at the surface of an underlying fluid and locally reduce the free energy.…”

“…Quantitative experiments began with the work of Agnes Pockels, whose letter to Lord Rayleigh was published in Nature [2] and describes the effect of kitchen powders on surface tension. The techniques developed in their early work are alive today [3] in the form of Langmuir-Blodgett troughs used to study molecular monolayers on fluid surfaces.Studies of surface tension driven spreading began first on deep fluid layers [4], but in more recent decades, thin fluid films have been recognized as underlying many complex biological and engineering processes.Applications include pulmonary drug delivery [5] and surfactant replacement therapy [6], ocular surfactants and blinking dynamics [7,8], solute transport [9], latex paint drying [10-12], ink-jet printing [13], and secondary oil recovery [14,15]. In each of these processes, amphiphilic surfactant molecules relax the arXiv:1309.3537v2 [physics.flu-dyn] 11 Feb 2014 2 intermolecular bonds at the surface of an underlying fluid and locally reduce the free energy.…”

P‐120: Inkjet‐Printable Composite Electrode and Device Architectures for the Inverted Phosphorescent OLED

“…Techniques such as soft lithography and imprinting for the fabrication of grid electrode pattern are known [1][2], but it requires a fastidious process step such as producing a flat mold of large scaling or exposure/ development. Therefore, the direct printing process such as inkjet is advantageous and possibly more suitable for the fabrication of organic semiconductor-based devices [3]. For a development of active-matrix (AM) OLEDs, which is already utilized in commercial mobile display, low-temperature polycrystalline silicon (LTPS) thin film transistor has many merits such as high mobility, stability, and n-type / p-type selectivity.…”