Marangoni spreading and contracting three-component droplets on completely wetting surfaces

Cira, Nate; Baumgartner, Dieter; Sinha, Shayandev; Karpitschka, Stefan

doi:10.1073/pnas.2120432119

Cited by 23 publications

(18 citation statements)

References 33 publications

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“…In figure 7, the fluid dynamics is neglected. By considering the complex fluid dynamics of multicomponent evaporation, some other phenomena can be observed, such as Ouzo effect (Diddens et al 2017;Lohse & Zhang 2020), pancake structure (Pahlavan et al 2021), precursor film , interfacial instability (Keiser et al 2017;Baumgartner et al 2022) and Taylor dispersion (Charlier et al 2022).…”

Section: Evaporationmentioning

confidence: 99%

A thermodynamically consistent diffuse interface model for the wetting phenomenon of miscible and immiscible ternary fluids

Wang,

Zhang,

et al. 2023

J. Fluid Mech.

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The wetting effect has attracted great scientific interest because of its natural significance as well as technical applications. Previous models mostly focus on one-component fluids or binary immiscible liquid mixtures. Modelling of the wetting phenomenon for multicomponent and multiphase fluids is a knotty issue. In this work, we present a thermodynamically consistent diffuse interface model to describe the wetting effect for ternary fluids, as an extension of Cahn's theory for binary fluids. In particular, we consider both immiscible and miscible ternary fluids. For miscible fluids, we validate the equilibrium contact angle and the thermodynamic pressure with Young's law and the Young–Laplace equation, respectively. Distinct flow patterns for dynamic wetting are presented when the surface tension and the viscous force dominate the wetting effect. For immiscible ternary fluids, we manipulate the wettability of two contact droplets deposited on a solid substrate according to three scenarios: (I) both droplets are hydrophilic; (II) a hydrophilic droplet in contact with a hydrophobic one; (III) both droplets are hydrophobic. The contact angles at each triple junction from the simulations are compared with Young's contact angle and Neumann's triangle rule. Simulations for the validation of our work are performed in two and three dimensions. In addition, we model the evaporation process of a ternary droplet and obtain the same power law as that of previous experiments. Our model allows one to relate the interfacial energies with surface composition, enabling the modelling of the coffee-ring phenomenon in further perspective.

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Section: Evaporationmentioning

confidence: 99%

A thermodynamically consistent diffuse interface model for the wetting phenomenon of miscible and immiscible ternary fluids

Wang,

Zhang,

et al. 2023

J. Fluid Mech.

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“…Nonetheless, models based on the lubrication approximation will be required when the mixtures components have similar vapor pressures to predict the temporal changes in mixture composition. 18,29,30,68 ■ CONCLUSIONS This study investigates the evaporation of droplets containing octamethyltrisiloxane and ethanol on a wettable surface. The findings indicate that the droplets exhibited four distinct wetting dynamics: two contracting and two spreading.…”

Section: ■ Evaporation Rate and Drying Periodsmentioning

confidence: 99%

“…11−14 These factors influence the wetting dynamics and contact angle during evaporation. 15−17 Baumgartner et al 18 demonstrated that droplets containing a fully miscible ternary mixture (water, ethanol, and propylene glycol), deposited on completely wetting surfaces, exhibit rich wetting dynamics as selective evaporation and surface tension gradients can change the droplet shape and result in three different wetting behaviors. Furthermore, the aforementioned factors in multi-component droplet evaporation also play a crucial role in understanding deposit patterns when polymers or particles are included.…”

Section: ■ Introductionmentioning

confidence: 99%

“…The dynamics of evaporation in multicomponent droplets, containing two or more liquids, give rise to increased complexity owing to selective evaporation, surface tension gradients, and thermal effects. − These factors influence the wetting dynamics and contact angle during evaporation. − Baumgartner et al demonstrated that droplets containing a fully miscible ternary mixture (water, ethanol, and propylene glycol), deposited on completely wetting surfaces, exhibit rich wetting dynamics as selective evaporation and surface tension gradients can change the droplet shape and result in three different wetting behaviors. Furthermore, the aforementioned factors in multicomponent droplet evaporation also play a crucial role in understanding deposit patterns when polymers or particles are included. − Deposit patterns, for instance, a coffee ring or multiple deposits due to stick and slip motion of the droplet, are influenced by surface tension gradients, wetting dynamics, composition of the binary mixture, and evaporation dynamics. − …”

Section: Introductionmentioning

confidence: 99%

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Liquid–Liquid Phase Separation Induced by Vapor Transfer in Evaporative Binary Sessile Droplets

Othman,

Poulos,

Torres

et al. 2023

Langmuir

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Drying of binary sessile droplets consisting of ethanol and octamethyltrisiloxane on a high-energy surface is investigated. During the process of evaporation, the droplets undergo liquid−liquid phase separation, resulting in the appearance of microdroplets at the liquid−air interface, which subsequently violently burst. This phase separation is attributed to water vapor transfer into the droplet, which modifies the solubility and leads to the formation of a ternary mixture. The newly formed ternary mixture may undergo nucleation and growth or spinodal decomposition, depending on the droplet composition path. By control of the relative humidity of air, phase separation can be mitigated or even eliminated. The droplets also display high mobility and complex wetting behavior due to phase separation, with two contracting and two spreading stages. The mass loss experiments reveal that the droplets undergo three distinct drying stages with an enhanced evaporation rate observed during the phase separation stage. A modified diffusion-limited model was employed to predict the evaporation rate, accounting for the physiochemical changes during evaporation and proved to be consistent with experimental observations. The findings of this work enhance our understanding of a coupled fundamental process involving the evaporation of multicomponent mixtures, wetting, and phase separation.

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“…Thus, evaporation in multicomponent liquids can trigger phenomenologically richer secondary processes compared to pure liquids. Such secondary processes include fluid flows [44,46,52], nontrivial contact line motion [53], segregation [49,54], and phase separation [48] (Figure 1.5). We discuss a few of these processes below: (a) Solutal Marangoni flow by selective evaporation Selective evaporation of the more volatile liquid in droplets and capillaries results in spatial gradients in concentration.…”

mentioning

confidence: 99%

Physicochemical hydrodynamics in confined multicomponent liquids

Raju

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When a system contains more than one liquid, each liquid will evaporate depending on the volatility and the composition close to the evaporating interface. Based on Raoult's law [50] and the non-ideality of the mixture, the concentration of water-vapor close to the surface is modified aswhere a w is the thermodynamic activity of water, x w the mole fraction of water in the liquid, and ψ w (x w ) the activity coefficient of water corresponding to x w [51]. For an ideal mixture, a w = x w and ψ w = 1. Thus, for multicomponent liquids, the local evaporation rate changes with changes in the local composition. Therefore, to determine the evaporation rates in such systems, one can resort to numerical simulations to easily account for the spatio-temporal changes in composition and mixture properties [46]. However, in Chapters 2 and 5, we will show cases where we can still analytically determine the evaporation rates for multicomponent mixtures, albeit under simplifying assumptions, which will be complemented by corresponding direct numerical simulations. Evaporation-induced secondary processesSimilar to pure liquids, evaporation of multicomponent liquids can produce capillary flow, thermal Marangoni flow, and buoyancy-driven flow. However, in multicomponent liquids, the secondary processes also result from the spatiotemporal changes in the composition. Thus, evaporation in multicomponent liquids can trigger phenomenologically richer secondary processes compared to pure liquids. Such secondary processes include fluid flows [44,46,52], nontrivial contact line motion [53], segregation [49,54], and phase separation [48] (Figure 1.5). We discuss a few of these processes below: (a) Solutal Marangoni flow by selective evaporation Selective evaporation of the more volatile liquid in droplets and capillaries results in spatial gradients in concentration. Such spatial concentration gradients can lead to gradients in interfacial tension. Surface tension gradients lead to flows which are termed as solutal Marangoni flows [46, 52] (Figure 1.5 a), in contrast to the thermal Marangoni flows that are caused by temperature gradients. The direction of solutal Marangoni flow depends on whether 1.4. EVAPORATION OF MULTICOMPONENT LIQUIDS 13 14 CHAPTER 1. INTRODUCTION 1.5. EVAPORATION-INDUCED SELF-ASSEMBLY OF PARTICLES 15 1.5. EVAPORATION-INDUCED SELF-ASSEMBLY OF PARTICLES 17 18 CHAPTER 1. INTRODUCTION Chapter 4. System: Particles dispersed in an evaporating ternary ouzo droplet. Questions: Does modifying the surface properties of particles affect the supraparticles formed using self-lubricating ouzo droplets? If yes, which surface modifications have a stronger influence on the supraparticle formation? Chapter 5 System: Binary mixture of water and glycerol in thin capillaries. Questions: How is the evaporation of a binary mixture in a capillary different from that of a pure liquid? Can we analytically model the evaporation of binary liquid mixtures in a capillary? What are the important control parameters that determine the evaporation behav...

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Marangoni spreading and contracting three-component droplets on completely wetting surfaces

Cited by 23 publications

References 33 publications

A thermodynamically consistent diffuse interface model for the wetting phenomenon of miscible and immiscible ternary fluids

A thermodynamically consistent diffuse interface model for the wetting phenomenon of miscible and immiscible ternary fluids

Liquid–Liquid Phase Separation Induced by Vapor Transfer in Evaporative Binary Sessile Droplets

Physicochemical hydrodynamics in confined multicomponent liquids

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