Coalescence, evaporation and particle deposition of consecutively printed colloidal drops

Yang, Xiulun; Chhasatia, Viral; Shah, Jaymeen; Sun, Ying

doi:10.1039/c2sm25906k

Cited by 28 publications

(21 citation statements)

References 31 publications

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“…Furthermore, it is of great interest to investigate the coalescence between two droplets, which is crucial for printing continuous lines with sharp edges. Controlling the TCL behavior during coalescing of the droplets by the dynamic wettability of the substrates should be developed . Moreover, it is also important to control the multi‐droplets overlapping in vertical direction for constructing high‐resolution three‐dimensional (3D) structures.…”

Section: Discussionmentioning

confidence: 99%

Controllable Printing Droplets for High‐Resolution Patterns

2014

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Inkjet printing has attracted wide attention due to the important applications in fabricating biological, optical, and electrical devices. During the inkjet printing process, the solutes prefer to deposit along the droplet periphery and form an inhomogeneous morphology, known as the coffee-ring effect. Besides, the feature size of printed dots or lines of conventional inkjet printing is usually limited to tens or even hundreds of micrometers. The above two issues greatly restrict the extensive application of printed patterns in high-performance devices. This paper reviews the recent advances in precisely controlling the printing droplets for high-resolution patterns and three-dimensional structures, with a focus on the development to suppress the coffee-ring effect and minimize the feature size of printed dots or lines. A perspective on the remaining challenges of the research is also proposed.

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Section: Discussionmentioning

confidence: 99%

Controllable Printing Droplets for High‐Resolution Patterns

2014

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“…Regardless of this, most previous studies in droplet deposition have focused only on the external dynamics-e.g., the freesurface shape, extent of spreading, and final footprint of the composite droplet [8][9][10][11][12][13]-and only a few works have explored the internal dynamics or mixing [5,7,14,15].…”

Section: Introductionmentioning

confidence: 99%

“…Yang et al [5] explored the movement of fluorescent particles during evaporation of a composite droplet formed from two consecutively printed droplets, focusing on particle deposition dynamics. Both of the above works relied on viewing the coalescence process from below and using transparent droplets, so (in the case of PIV) seeding particles could be identified and analyzed to compute the internal flow.…”

Section: Introductionmentioning

confidence: 99%

“…Coalescence and mixing of droplets on a solid surface are of great interest not only to the established inkjet printing industry but also to emerging applications such as the noncontact printing of functional electronics and biological materials and in the fields of microfluidic devices, microchemistry, and fast prototyping [1][2][3][4][5]. The advantages of the inkjet printing of liquid materials over traditional delivery techniques are many and based on the technological ability of printheads to generate homogeneously sized droplets on demand at a determined speed and direction.…”

Section: Introductionmentioning

confidence: 99%

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Mixing and internal dynamics of droplets impacting and coalescing on a solid surface

et al. 2013

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The coalescence and mixing of a sessile and an impacting liquid droplet on a solid surface are studied experimentally and numerically in terms of lateral separation and droplet speed. Two droplet generators are used to produce differently colored droplets. Two high-speed imaging systems are used to investigate the impact and coalescence of the droplets in color from a side view with a simultaneous gray-scale view from below. Millimeter-sized droplets were used with dynamical conditions, based on the Reynolds and Weber numbers, relevant to microfluidics and commercial inkjet printing. Experimental measurements of advancing and receding static contact angles are used to calibrate a contact angle hysteresis model within a lattice Boltzmann framework, which is shown to capture the observed dynamics qualitatively and the final droplet configuration quantitatively. Our results show that no detectable mixing occurs during impact and coalescence of similar-sized droplets, but when the sessile droplet is sufficiently larger than the impacting droplet vortex ring generation can be observed. Finally we show how a gradient of wettability on the substrate can potentially enhance mixing.

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“…Often the fluid in these applications tends to display non-Newtonian behavior. Characterizing the fundamental dynamics of spreading of Newtonian liquid droplets has received much attention in a large body of the literature (Chandra and Avedisian, 1991;Asai et al, 1993;Pasandideh-Fard et al, 1996;Mao et al, 1997;Sadhal et al, 1997;Rioboo et al, 2001;ikalo et al, 2002;Roisman et al, 2002;Ukiwe and Kwok, 2005;Šikalo and Ganiç, 2006;Yarin, 2006;Gatne et al, 2007;Sanjeev et al, 2008;Gatne et al, 2009;Ravi et al, 2010), and so also have been the efforts to delineate the drop-surface interactions in a variety of applications that range from macroscale processes to microscale devices (Jones, 1971;Madejski, 1976;Collings et al, 1990;Castrejón-Pita et al, 2011;Yang et al, 2012Yang et al, , 2013 as well as several others). For velocities below the splashing limit, the drop tends to spread on the surface to form a thin lamella.…”

Section: Introductionmentioning

confidence: 99%

Effects of Pseudoplasticity on Spread and Recoil Dynamics of Aqueous Polymeric Solution Droplets on Solid Surfaces

Ravi

Jog

Manglik

2013

Interfac Phenom Heat Transfer

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The postimpact spreading and recoil behavior of millimeter-size liquid droplets of pure water, water-glycerol solution, and non-Newtonian aqueous solutions of medium-grade hydroxyl ethyl cellulose (HEC 250 MR) on dry horizontal hydrophobic (Teflon) and hydrophilic (glass) substrates is presented. The drop spread-recoil dynamics are captured using a high-speed high-resolution digital video recording and image processing. The non-Newtonian effects of aqueous polymeric solutions on postimpact spreading are contrasted with those for a water-glycerol solution with identical surface tension and zero-shear rate viscosity. For a broad range of drop Weber numbers (20 ≤ We ≤ 200), dynamic visualized records of impact, spreading, and recoil are presented along with their measured temporal variations in dropdiameter-scaled spread and film height. The shear-rate-dependent viscosity of the polymer solution is found to give rise to highly complex spread-recoil dynamics compared to Newtonian liquids. During initial spread, because the shear rate tends to be high, shear-thinning or pseudoplasticity effects manifest in polymer solution drops to alter their spread dynamics. Contrarily, during recoil their higher low-shear apparent viscosity tends to retard recoil and dampen shape oscillations. Shear-rate-dependent non-Newtonian behavior is further seen at low We (low shear rate during spreading), where the maximum spread of HEC solution droplets is comparable to that of high-viscosity water-glycerol solution, whereas at high We (high shear rate during spreading), their maximum spreads are closer to those of low-viscosity water droplets.

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Coalescence, evaporation and particle deposition of consecutively printed colloidal drops

Cited by 28 publications

References 31 publications

Controllable Printing Droplets for High‐Resolution Patterns

Controllable Printing Droplets for High‐Resolution Patterns

Mixing and internal dynamics of droplets impacting and coalescing on a solid surface

Effects of Pseudoplasticity on Spread and Recoil Dynamics of Aqueous Polymeric Solution Droplets on Solid Surfaces

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