Lines of dense nanoparticle colloidal suspensions evaporating on a flat surface: Formation of non-uniform dried deposits

Yarin, Alexander L.; Szczech, John; Megaridis, Constantine M.; Zhang, J.; Gamota, Daniel

doi:10.1016/j.jcis.2005.07.032

Cited by 38 publications

(28 citation statements)

References 17 publications

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“…[11,22,29]), we expect the extended version of our model to reproduce this behavior as well. Additionally, the framework can readily be used for two-dimensional drops [14] by writing the equations in the bipolar coordinates instead of the toroidal (see, e.g., Ref. [50]).…”

Section: Discussionmentioning

confidence: 99%

Alternative mechanism for coffee-ring deposition based on active role of free surface

et al. 2016

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When a colloidal sessile droplet dries on a substrate, the particles suspended in it usually deposit in a ring-like pattern. This phenomenon is commonly referred to as the "coffee-ring" effect. One paradigm for why this occurs is as a consequence of the solutes being transported towards the pinned contact line by the flow inside the drop, which is induced by surface evaporation. From this perspective, the role of the liquid-gas interface in shaping the deposition pattern is somewhat minimized. Here, we propose an alternative mechanism for the coffee-ring deposition. It is based on the bulk flow within the drop transporting particles to the interface where they are captured by the receding free surface and subsequently transported along the interface until they are deposited near the contact line. That the interface captures the solutes as the evaporation proceeds is supported by a Lagrangian tracing of particles advected by the flow field within the droplet. We model the interfacial adsorption and transport of particles as a one-dimensional advection-generation process in toroidal coordinates and show that the theory reproduces ring-shaped depositions. Using this model, deposition patterns on both hydrophilic and hydrophobic surfaces are examined in which the evaporation is modeled as being either diffusive or uniform over the surface.

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Section: Discussionmentioning

confidence: 99%

Alternative mechanism for coffee-ring deposition based on active role of free surface

et al. 2016

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“…It may, therefore, buckle inward, leading to a dimple at the top of the droplet, which can under some conditions grow into a hole, leading to a toroidal deposit . For similar reasons dimple can also form during drying of a semicylindrical 2‐D linear “droplet” containing a concentrated colloidal suspension, used for example in printing …”

Section: Deposition Patternsmentioning

confidence: 99%

Transport and deposition patterns in drying sessile droplets

2014

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The literature on drying sessile droplets and deposition of suspended material is reviewed including the simple explanation of the "coffee ring" deposit given by Deegan et al.1 Analytical and numerical solutions for the flow are given, including the effect of Marangoni stresses, pinning or movement of the contact line, and viscous, thermal, gravitational, and other effects. The solution space is explored using dimensionless groups governing mass, momentum, and heat transfer effects in the droplet, external gas, and substrate. The most common types of deposition patterns are summarized, including those produced by pinned contact lines, sticking-and-slipping contact lines, and Marangoni effects. The influence of contact-line deposits is also reviewed, and the effects of colloidal, polymeric, and other depositing materials. Advanced applications from ink-jet printing to disease diagnosis are discussed as well. The review helps readers take stock of what has been learned and what remains incompletely explained.

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“…Segregation of particles implies lateral flow of particles occurring from the center to the edges of a hydrophilic stripe. The formation of non-uniform deposits of colloidal particles on substrates has been studied by several authors [35][36][37][38][39][40][41]. However, the effect of concentration of particles has not been discussed in these studies.…”

Section: Formation Of Uniform and Segregated Coatingsmentioning

confidence: 99%

Dip coating of charged colloidal suspensions onto substrates with patterned wettability: Coating regime maps

Reynolds

Kalpathy

Kumar

et al. 2010

Journal of Colloid and Interface Science

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Lines of dense nanoparticle colloidal suspensions evaporating on a flat surface: Formation of non-uniform dried deposits

Cited by 38 publications

References 17 publications

Alternative mechanism for coffee-ring deposition based on active role of free surface

Alternative mechanism for coffee-ring deposition based on active role of free surface

Transport and deposition patterns in drying sessile droplets

Dip coating of charged colloidal suspensions onto substrates with patterned wettability: Coating regime maps

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