Dynamics of dielectric liquid rise between parallel electrodes under capillary and dielectrophoretic forces

Lackowski, M.; Nowakowska, H.

doi:10.1088/1361-6463/aaa30f

Cited by 5 publications

(3 citation statements)

References 44 publications

(88 reference statements)

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“…This has been demonstrated before ,, through electrowetting via different approaches. Lackowski et al illustrated this by including a contact line resistance in their analysis. Wang and Jones used Maxwell’s stress tensor in combination with electrical circuit analysis to investigate electrowetting and its effects on the height rise of various solutions. , Hong et al looked at the time response of the electrowetting effect on height rise using an overdrive voltage.…”

Section: Introductionmentioning

confidence: 99%

Effects of Frequency and Joule Heating on Height Rise between Parallel Electrodes with AC Electric Fields

2022

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High strength AC electric fields generate a body force on a dielectric medium confined between two electrodes. The body forces are due to two factors. First is the variation in permittivity across an interface such as liquid–air present between the electrodes. The second is a change in the dielectric property of the medium due to a variation in the thermodynamic properties such as temperature. The height rise of a dielectric medium between two electrodes is one of the consequences of these electrical body forces and is used here as a comparatively simple way to study these forces. In an aqueous solution with finite conductivity, the effects of the frequency of the supplied voltage source and the temperature change due to Joule heating on height rise have never been studied in this context. This study focuses on systems where the contributions of surface forces are negligible and highlights the interplay between solution conductivity, applied electric field, and the solution height/temperature behavior. Using a generic thermodynamic model for an aqueous solution under the application of an alternating current electric field, it is shown that for low conductivity solutions the resulting temperature and height rise change weakly with the applied field frequency and strongly with the applied electric field. For higher conductivity solutions, the behavior becomes more complex with respect to the electric field strength. As compared to Pellat’s original model, the height rise varies from strongly suppressed to enhanced.

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Section: Introductionmentioning

confidence: 99%

Effects of Frequency and Joule Heating on Height Rise between Parallel Electrodes with AC Electric Fields

2022

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“…The electromechanical approach of electrowetting explains the dipole water molecule’s charge dynamics and electric field concentration in electrowetting. Several studies [ 17 , 18 , 19 , 20 ] have used this approach and associated equations to explain electrowetting phenomena. In this study, we also used the same approach and related equations.…”

Section: Theoretical Background On Dipole Water Molecule’s Charge Dyn...mentioning

confidence: 99%

Influence of the Ground Electrode on the Dynamics of Electrowetting

2023

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The ability to manipulate a liquid meniscus using electrowetting has many applications. In any electrowetting design, at least two electrodes are required: one forms the field to change the contact angle and the other functions as a ground electrode. The contribution of the ground electrode (GE) to the dynamics of electrowetting has not yet been thoroughly investigated. In this paper, we discovered that with a bare ground electrode, the contact angle of a sessile drop increases instead of decreases when a direct current (DC) voltage varying from zero to the threshold voltage is applied. This phenomenon is opposite to what occurs when the GE is coated with a dielectric, where the contact-angle change follows the Lippmann–Young equation above the threshold voltage of electrowetting. However, this behaviour is not observed with either a dielectric-coated electrode using direct current (DC) or a bare ground electrode using alternating current (AC) voltage electrowetting. This study explains this phenomenon with finite element simulation and theory. From previous research work, the ground electrode configuration is inconsistent. In some studies, the ground electrode is exposed to water; in other studies, the ground electrode is covered with dielectric. This study identified that an exposed ground electrode is not required in electrowetting. Moreover, this research work suggests that for applications where precise control of the contact angle is paramount, a dielectric-coated ground electrode should be used since it prevents the increase in the contact angle when increasing the applied potential from zero to the threshold voltage. This study also identified that contact angle hysteresis is lower with a Cytop-coated ground electrode and DC voltage than with a bare ground electrode using AC or DC voltages.

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“…Chen et al [34] realized the liquid transportation and created a droplet containing a single bead by LDEP. Lackowski and Nowakowska [35] showed that isopropanol (2-propanol, C 3 H 8 O) was suitable for presenting LDEP effect in capillary systems and analyzed the influence of the LDEP force on a temporal dependence of the liquid height-of-rise.…”

Section: Programmable Liquid Matter Via External Fieldmentioning

confidence: 99%

Programmable intelligent liquid matter: material, science and technology

Zhou¹,

Zu²,

Liu³

2022

J. Micromech. Microeng.

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Intelligent responses, transformation and desired delivery of liquids involve the intersection among materials, physics, and chemistry. The precise programmed operation has been found rather significant in many emerging fields, such as microfluidic devices, digital fluids, intelligent matter, responsive liquid machines, interactive display, soft robotic system and drug delivery, etc. This article is dedicated to presenting a comprehensive review of recent advances in the programmable actuation of liquid matter controlled by unique substrate structures and various physical fields. First, the fundamental theories of asymmetric surface microstructure and specifically administrated external effects such as electric, magnetic, acoustic, light, and thermal fields to drive droplets are illustrated. Then, we compare the advantages and disadvantages of these typical technological strategies. Furthermore, the practical multifunctional extension of programmable liquids based on different actuation mechanisms is presented. Finally, we summarize the design schemes of programming units for liquid matter and give perspective on possible future research directions, providing a brief reference for researchers interested in the field.

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Dynamics of dielectric liquid rise between parallel electrodes under capillary and dielectrophoretic forces

Cited by 5 publications

References 44 publications

Effects of Frequency and Joule Heating on Height Rise between Parallel Electrodes with AC Electric Fields

Effects of Frequency and Joule Heating on Height Rise between Parallel Electrodes with AC Electric Fields

Influence of the Ground Electrode on the Dynamics of Electrowetting

Programmable intelligent liquid matter: material, science and technology

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