Experimental Droplet Study of Inverted Marangoni Effect of a Binary Liquid Mixture on a Nonuniform Heated Substrate

Ouenzerfi, Safouene; Harmand, Souad

doi:10.1021/acs.langmuir.5b04539

Cited by 31 publications

(13 citation statements)

References 29 publications

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“…Ouenzerfi et al [24] presented an experimental study on the inversion of the Marangoni effect of a drop of binary mixture (97% water -3% butanol) under a horizontal temperature gradient. They showed that a binary drop (97% water -3% butanol) tends to move to warmer areas.…”

Section: --------------mentioning

confidence: 99%

Study of the phenomenon of the interaction between sessile drops during evaporation

Khilifi¹,

Foudhil²,

Fahem³

et al. 2019

Therm sci

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This research work represents an experimental study of the interaction between water drops deposited on a substrate at ambient temperature. To examine this phenomenon, the evaporation of a single drop deposited on a substrate was first investigated. Then, several drops were deposited alongside on the same substrate under the same conditions. The central drop dynamic behavior was also examined and compared with that of a single drop. This comparison shows the effect of the interaction between the neighboring drops, which delayed the evaporation of these drops and particularly the central droplet, on evaporation. In fact, three configurations were studied by changing the initial distance, d, between the drops (d = 0.2 mm, d = 7 mm, and d = 15 mm). The obtained results reveal that the interaction phenomenon becomes less important by increasing the distance between the drops. This is important for optimizing many industrial applications, such as spray drying, fuel injection in combustion engines, and other applications.

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Section: --------------mentioning

confidence: 99%

Study of the phenomenon of the interaction between sessile drops during evaporation

Khilifi¹,

Foudhil²,

Fahem³

et al. 2019

Therm sci

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“…Notably, they reported that the internal flow direction is from the hot side to the cold side at the liquid-gas interface. Recently, Ouenzerfi and Harmand [29] observed an opposite migration of water-3% butanol binary droplet, i.e., from the cold side to the hot side, on a substrate with 0.5ºC/mm gradient. Authors attributed it to an increase in surface tension of the binary liquid with temperature, beyond a critical value of the temperature.…”

Section: Introductionmentioning

confidence: 99%

Colloidal deposit of an evaporating sessile droplet on a non-uniformly heated substrate

Malla

Bhardwaj

Neild

2020

Colloids and Surfaces A: Physicochemical and Engineering Aspect

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2 AbstractThe pattern and profile of a dried colloidal deposit formed after evaporation of a sessile water droplet containing polystyrene particles on a non-uniformly heated glass are investigated experimentally. In particular, the effects of temperature gradient across the substrate and particles size are investigated. The temperature gradient was imposed using Peltier coolers, and side visualization, infrared thermography, optical microscopy, and optical profilometry were employed to collect the data. On a uniformly heated substrate, a ring with an inner deposit is obtained, which is attributed to axisymmetric Marangoni recirculation and consistent with previous reports. However, the dimensions of the ring formed on a non-uniformly heated substrate are significantly different on the hot and cold side of the substrate and are found to be a function of the temperature gradient and particles size. In the case of smaller particle size, the contact line on hot side depins and together with twin asymmetric Marangoni recirculations, it results in a larger ring width on the cold side as compared to the hot side. In contrast, the contact line remains pinned in case of larger particles, and the twin asymmetric Marangoni recirculations advect more particles on the hot side, resulting in a larger ring width at the hot side. A mechanistic model is employed to explain why the depinning is dependent on the particle size. A larger temperature gradient significantly increases or decreases the ring width depending on the particle size, due to a stronger intensity recirculation. A regime map is proposed for the deposit patterns on temperature gradient-particle size plane to classify the deposits. Movie S6: Video of IR thermography of the evaporating droplet for d = 0.1 μm at dT/dX = 4.2ºC/mm.

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“…4,7,8 In addition to electrocapillary forces, alternative driving forces to manipulate droplets are available and they are based on thermal, 10-13 chemical, [13][14][15][16] and surface morphological gradients. [17][18][19] For example, thermal gradients cause surface tension gradients of a water droplet on a surface, creating thermal Marangoni forces [10][11][12][13] that may drive a water droplet in a favorable direction. Chemical gradients also causing surface tension gradients of a water droplet are achieved by applying functional groups to a surface with spatially varying densities [14][15][16] or changing chemical components upon temperature gradients.…”

Section: Literature Reviewmentioning

confidence: 99%

Droplet manipulation on a structured shape memory polymer surface

Park

Kim

2017

Lab Chip

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While methods for dynamic tuning of surface wettability to manipulate water droplets have been widely explored for many applications including digital microfluidics, those based on dynamically changeable surface morphology have remained challenging to achieve. In this work, we present a structured shape memory polymer (SMP) surface which shows dynamically tunable surface wettability through changeable surface morphology in order to manipulate water droplets. The structured SMP surface involves a SMP pillar array consisting of nanotextured small and large pillars which can change its morphology between permanent and temporary shapes upon thermomechanical loading. Specifically, the structured SMP surface dynamically creates a surface morphological gradient and changes its surface wettability during thermally induced shape recovery of the SMP pillar array. Different wetting characteristics of the structured SMP surface between permanent and temporary shapes are theoretically predicted and experimentally verified. Based on these measured wetting characteristics, the structured SMP surface is designed to demonstrate that the morphological difference between two shapes under a water droplet overcomes contact angle hysteresis, resulting in driving a water droplet, when combined with the thermal Marangoni effect.iii ACKNOWLEDGMENTS

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Experimental Droplet Study of Inverted Marangoni Effect of a Binary Liquid Mixture on a Nonuniform Heated Substrate

Cited by 31 publications

References 29 publications

Study of the phenomenon of the interaction between sessile drops during evaporation

Study of the phenomenon of the interaction between sessile drops during evaporation

Colloidal deposit of an evaporating sessile droplet on a non-uniformly heated substrate

Droplet manipulation on a structured shape memory polymer surface

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