Amplifying and attenuating the coffee-ring effect in drying sessile nanofluid droplets

Crivoi, Alexandru; Duan, Fei

doi:10.1103/physreve.87.042303

Cited by 51 publications

(51 citation statements)

References 19 publications

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“…[21][22][23][24][25][26][27] More specifically, Still et al 22 achieved a uniform deposition of colloidal particles on glass by adding Sodium dodecyl sulfate (SDS) to the drop dispersion.…”

Section: -12mentioning

confidence: 99%

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Evaporation of Sessile Droplets Laden with Particles and Insoluble Surfactants

2016

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We consider the flow dynamics of a thin evaporating droplet in the presence of an insoluble surfactant and non-interacting particles in the bulk. Based on lubrication theory, we derive a set of evolution equations for the film height, the interfacial surfactant and bulk particle concentrations, taking into account the dependence of the liquid viscosity on the local particle concentration. An important ingredient of our model is that it takes into account the fact that the surfactant adsorbed at the interface hinders evaporation. We perform a parametric study to investigate how the presence of surfactants affects the evaporation process as well as the flow dynamics with and without the presence of particles in the bulk. Our numerical calculations show that the droplet life-time is affected significantly by the balance between the ability of surfactant to * To whom correspondence should be addressed † Department of Chemical Engineering, University of Patras, Patras 26500, Greece ‡ Department of Chemical Engineering, Indian Institute of Technology Hyderabad, Sangareddy 502 285, Telangana, India ¶ Department of Chemical Engineering, Imperial College London, London SW7 2AZ, UK 1 enhance spreading suppressing the effect of thermal Marangoni stresses-induced motion and to hinder the evaporation flux through the reduction of effective interfacial are of evaporation, which tend to accelerate and decelerate the evaporation process, respectively. For particle-laden droplets and in the case of dilute solutions, the droplet life-time is found to be weakly-dependent on the initial particle concentration. We also show that the particle deposition patterns are influenced strongly by the direct effect of surfactant on the evaporative flux; in certain cases, the "coffee stain" effect is enhanced significantly. A discussion of the delicate interplay between the effects of capillary pressure, solutal and thermal Marangoni stresses, which drive the liquid flow inside the evaporating droplet giving rise to the observed results is provided herein.

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“…[21][22][23][24][25][26][27] More specifically, Still et al 22 achieved a uniform deposition of colloidal particles on glass by adding Sodium dodecyl sulfate (SDS) to the drop dispersion.…”

Section: -12mentioning

confidence: 99%

“…However, Crivoi and Duan 25,26 have shown that the formation of coffee ring of graphite nanoparticles is enhanced with the addition of Cetyltrimethyl Ammonium Bromide (CTAB)…”

Section: Sempels Et Almentioning

confidence: 99%

Evaporation of Sessile Droplets Laden with Particles and Insoluble Surfactants

2016

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“…Crivoi and Duan studied the effect of hexadecyltrimethylammonium bromide on the deposit morphology obtained by evaporating droplets of dispersed aluminium oxide nanoparticles on Si wafers 31. In the surfactant‐free dispersions, particles tended to aggregate into clusters, which upon drying deposited into a uniform layer enclosed by a visible ring.…”

Section: Interactions Of Particles With/at Interfaces Affecting Thmentioning

confidence: 99%

“…By varying the particle sticking probability from 0 to 100 %, a continuous transformation from a coffee ring to a uniform pattern was observed in the simulations. Therefore, controlling the particle sticking probability by modifying the fluid properties (in this case by the addition of surfactants) offered a way to manipulate the self‐assembly patterns formed from evaporating drops 31…”

Section: Interactions Of Particles With/at Interfaces Affecting Thmentioning

confidence: 99%

Corrigendum: N‐Oxide 1,2,4,5‐Tetrazine‐Based High‐Performance Energetic Materials

Wei¹,

Gao²,

Shreeve³

2015

Chemistry A European J

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“…This highly nonuniform deposition is known as the coffee‐ring effect; it is produced when the drop edges are pinned during evaporation and subsequent radial capillary flows from the drop center carry suspended solutes to the drop perimeter . The coffee‐ring effect, however, can be ameliorated in aqueous systems of large (>10 μm) suspended spheres, in suspensions of ellipsoidal particles with strong capillary interactions, via electrowetting, in systems with strong attractive forces between particles and substrate, and in the presence of surfactants that lead to strong Marangoni flows, among other techniques . In these cases, the drying drop system provides experimenters with an opportunity to make uniform thin particle coatings and films.…”

Section: Introductionmentioning

confidence: 99%

Temperature‐Sensitive Hydrogel‐Particle Films from Evaporating Drops

Still

Yunker

Hanson

et al. 2015

Adv Materials Inter

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that was initially suspended. This highly nonuniform deposition is known as the coffee-ring effect; it is produced when the drop edges are pinned during evaporation and subsequent radial capillary fl ows from the drop center carry suspended solutes to the drop perimeter. [5][6][7] The coffeering effect, however, can be ameliorated in aqueous systems of large (>10 µm) suspended spheres, [ 8 ] in suspensions of ellipsoidal particles with strong capillary interactions, [ 9 ] via electrowetting, [ 10 ] in systems with strong attractive forces between particles and substrate, [ 11 ] and in the presence of surfactants that lead to strong Marangoni fl ows, [ 12,13 ] among other techniques. [14][15][16] In these cases, the drying drop system provides experimenters with an opportunity to make uniform thin particle coatings and fi lms.The present contribution builds on investigations of Horigome and Suzuki, which demonstrated that drying aqueous suspensions of PNIPAM particles on polystyrene substrates did not yield typical coffee-ring deposition. [ 17 ] Rather, the hydrogel particles tend to act as amphiphilic moieties, populating the air-water interface fairly uniformly during evaporation. [ 18 ] This behavior, also observed for linear PNIPAM polymers, [ 19,20 ] induces a predominantly uniform deposition of hydrogel particles on the substrate. In our work, we employ micrometersize (diameter d = 1-4 µm) PNIPAM microgel particles with comonomer 2-aminoethylmethacrylate hydrochloride (AEMA) in the suspension. Importantly, the AEMA comonomer introduces primary amine groups onto the microgel particle surfaces that can be used for subsequent cross-linking. Much smaller (<100 nm) PNIPAM particles are feasible, [ 21 ] but systematic studies on the introduction of amine groups still have to be performed. On the other end of the spectrum, we can prepare functionalized particles with amine groups up to approximately 10 µm with the referenced methods. Even larger particles are achievable using microfl uidic techniques.After the water has evaporated, a mostly uniform microgel particle fi lm remains on the substrate. It is kept untouched for another 24 h to ensure cross-linking of neighboring particles by glutaraldehyde that is also mixed into the original droplet suspension. The resultant hydrogel-particle fi lm is temperature-sensitive because the hydrogel particles that compose it are temperature-sensitive. Thus, fi lm size, shape, porosity, and even optical properties are readily varied with temperature control.Our novel responsive fi lms can be utilized as membranes that differ from fi lm structures that have been previously A simple method to prepare temperature-sensitive fi lms composed of micrometer-sized colloidal hydrogel particles using evaporating drops of colloidal suspensions is demonstrated. The fi lms range in thickness from a monolayer to approximately fi fty particle diameters depending on initial particle volume fraction. Sessile droplets of hydrogel-particle suspensions are evaporated on silicon wafers. The fi lm i...

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Amplifying and attenuating the coffee-ring effect in drying sessile nanofluid droplets

Cited by 51 publications

References 19 publications

Evaporation of Sessile Droplets Laden with Particles and Insoluble Surfactants

Evaporation of Sessile Droplets Laden with Particles and Insoluble Surfactants

Corrigendum: N‐Oxide 1,2,4,5‐Tetrazine‐Based High‐Performance Energetic Materials

Temperature‐Sensitive Hydrogel‐Particle Films from Evaporating Drops

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