Lift-off of a conducting sessile drop in an electric field

Glière, Alain; Roux, Jean-Maxime; Achard, Jean‐Luc

doi:10.1007/s10404-013-1144-6

Cited by 12 publications

(18 citation statements)

References 21 publications

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“…Besides the aforementioned parameters, the wetting properties of a solid surface such as the Young's angle and contact-angle hysteresis also have influence on the detachment of droplets, especially the critical voltage for droplet detachment. Achard and his coworkers 17,18,42 reported that a droplet sitting on the lower electrode in an immiscible fluid can lift toward the upper substrate by electrostatic force, which is affected by the contact-angle hysteresis, especially the receding contact angle. For EW-driven detachment of droplets in air media, the threshold voltage for droplet detachment on superhydrophobic surfaces is smaller than that on hydrophobic surfaces due to lower contact-angle hysteresis of the superhydrophobic surfaces.…”

Section: Resultsmentioning

confidence: 99%

“…Detachment of droplets from a solid surface is one of the essential and crucial processes in numerous practical applications in the field of digital (or droplet-based) microfluidics (DMF), [1][2][3] including cell culture, [4][5][6][7][8] electronic cooling, 9,10 and cleaning and sampling of microparticles. [11][12][13] Several methods for detaching droplets from a solid surface have been proposed; examples of these methods include mechanical vibration, 14,15 electrostatic forces, [16][17][18] and nanoparticle suspensions. [19][20][21] However, these methods have technological problems, such as noise generation and difficulty in integration due to mechanical moving parts, high voltage (~a few kV) or high electric field (~MV m −1 ), and the addition of surfactants or nanoparticles.…”

Section: Introductionmentioning

confidence: 99%

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Detaching droplets in immiscible fluids from a solid substrate with the help of electrowetting

Hong

Lee

2015

Lab Chip

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The detachment (or removal) of droplets from a solid surface is an indispensable process in numerous practical applications which utilize digital microfluidics, including cell-based assay, chip cooling, and particle sampling. When a droplet that is fully stretched by impacting or electrowetting is released, the conversion of stored surface energy to kinetic energy can lead to the departure of the droplet from a solid surface. Here we firstly detach sessile droplets in immiscible fluids from a hydrophobic surface by electrowetting. The physical conditions for droplet detachment depend on droplet volume, viscosity of ambient fluid, and applied voltage. Their critical conditions are determined by exploring the retracting dynamics for a wide range of driving voltages and physical properties of fluids. The relationships between physical parameters and dynamic characteristics of retracting and jumping droplets, such as contact time and jumping height, are also established. The threshold voltage for droplet detachment in oil with high viscosity is largely reduced (~70%) by electrowetting actuations with a square pulse. To examine the applicability of three-dimensional digital microfluidic (3D-DMF) platforms to biological applications such as cell culture and cell-based assays, we demonstrate the detachment of droplets containing a mixture of human umbilical vein endothelial cells (HUVECs) and collagen (concentration of 4 × 10(4) cells mL(-1)) in silicone oil with a viscosity of 0.65 cSt. Furthermore, to complement the technical limitations due to the use of a needle electrode and to demonstrate the applicability of the 3D-DMF platform with patterned electrodes to chemical analysis and synthesis, we examine the transport, merging, mixing, and detachment of droplets with different pH values on the platform. Finally, by using DC and AC electrowetting actuations, we demonstrate the detachment of oil droplets with a very low contact angle (<~13°) in water on a hydrophobic surface.

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Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Detaching droplets in immiscible fluids from a solid substrate with the help of electrowetting

Hong

Lee

2015

Lab Chip

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“…The experimental studies summarised in Table 1, focused on the change in the contact angle for dielectric liquids under an external electric field varying from 1 to 25 kV/cm. The overall mean of these results suggested an increase or decrease in the contact angle with increasing magnitude of the electric field [17,[45][46][47][48][49][50].…”

Section: Influence Of An Electrical Field On the Wetting Angle Of A Dropmentioning

confidence: 99%

Wetting and evaporation of a sessile drop under an external electrical field: A review

Vancauwenberghe

Marco

Brutin

2013

Colloids and Surfaces A: Physicochemical and Engineering Aspect

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The enhancement of heat and mass transfer using a static electric field is an interesting process for industrial applications, due to its low energy consumption and potentially high level of evaporation rate enhancement. However, to date, this phenomenon is still not understood in the context of the evaporation of sessile drops. We synthesise the current research concerning the effect of an electric field on sessile drops with a focus on the change of contact angle and shape and the influence of the evaporation rate. We also discuss the future prospects of this research field

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“…In their works on the liftoff of a conducting drop, Roux et al (Roux and Achard, 2009;Gliere et al, 2013) observed a decrease in the contact angle of a water drop placed on the lower plate electrode of a condenser surrounded by mineral oil with a high relative permittivity. The overall mean of these results suggested an increase or decrease in the contact angle with increasing magnitude of the electric field.…”

Section: Wetting Contact Anglementioning

confidence: 99%