Thermal conductance switching based on the actuation of liquid droplets through the electrowetting on dielectric (EWOD) phenomenon

Cha, Gilhwan; Kim, Chang‐Jin; Ju, Y. Sungtaek

doi:10.1016/j.applthermaleng.2015.11.098

Cited by 30 publications

(21 citation statements)

References 19 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Electrowetting: The contact angle (wettability) between a droplet and a dielectric substrate can be changed with an electric field. 193 Cha et al 194 developed an electrowetting thermal switch with two parallel plates and a liquid droplet on the dielectric bottom plate. The droplet height depends on the contact angle, so a DC voltage can switch between droplet contact and noncontact with the upper plate using the electrowetting effect, showing r ¼ 2.4 for water droplets.…”

Section: Controlling Fluid Heat Transfer With Electric and Magnetic Fmentioning

confidence: 99%

Thermal diodes, regulators, and switches: Physical mechanisms and potential applications

Wehmeyer

Yabuki

Monachon

et al. 2017

Applied Physics Reviews

381

261

View full text Add to dashboard Cite

Interest in new thermal diodes, regulators, and switches has been rapidly growing because these components have the potential for rich transport phenomena that cannot be achieved using traditional thermal resistors and capacitors. Each of these thermal components has a signature functionality: Thermal diodes can rectify heat currents, thermal regulators can maintain a desired temperature, and thermal switches can actively control the heat transfer. Here, we review the fundamental physical mechanisms of switchable and nonlinear heat transfer which have been harnessed to make thermal diodes, switches, and regulators. The review focuses on experimental demonstrations, mainly near room temperature, and spans the fields of heat conduction, convection, and radiation. We emphasize the changes in thermal properties across phase transitions and thermal switching using electric and magnetic fields. After surveying fundamental mechanisms, we present various nonlinear and active thermal circuits that are based on analogies with well-known electrical circuits, and analyze potential applications in solid-state refrigeration and waste heat scavenging.

show abstract

Section: Controlling Fluid Heat Transfer With Electric and Magnetic Fmentioning

confidence: 99%

Thermal diodes, regulators, and switches: Physical mechanisms and potential applications

Wehmeyer

Yabuki

Monachon

et al. 2017

Applied Physics Reviews

381

261

View full text Add to dashboard Cite

show abstract

“…Among various approaches to control the droplet motion, electrowetting (EW) is particularly convenient and versatile for its ability to tune the surface wetting property with an external electric field. With EW, it is now possible to design digitized active and reconfigurable cooling devices for high-flux thermal management of compact microsystems [5][6][7][8].…”

Section: Introductionmentioning

confidence: 99%

Dynamics of droplet motion induced by Electrowetting

Sur

Pascente

et al. 2017

International Journal of Heat and Mass Transfer

View full text Add to dashboard Cite

Electrowetting (EW) has drawn significant interests due to the potential applications in electronic displays, lab-on-a-chip microfluidic devices and electro-optical switches, etc. However, current understanding of EW is hindered by the inadequacy of available numerical and theoretical methods in properly modeling the transient behaviors of EW-actuated droplets. In the present work, a combined numerical and experimental approach was employed to study the EW response of a droplet subject to both direct current (DC) and alternating current (AC) actuating signals. Computational fluid dynamics models were developed by using the Volume of Fluid (VOF)-Continuous Surface Force (CSF) method. A dynamic contact angle model based on the molecular kinetic theory was implemented as the boundary condition at the moving contact line, which considers the effects of the contact line friction and the pinning force. The droplet shape evolution under DC condition and the interfacial resonance oscillation under AC condition were investigated. It was found that the numerical models were able to accurately predict the key parameters of electrowetting-induced droplet dynamics.

show abstract

“…(3) By arranging electrodes side-by-side, electric potentials can be applied sequentially for basic liquid manipulations, such as droplet generation, movement, splitting, and merging. (6) Because it enables control over the droplet shape and liquid flow using only electrical signals, EWOD actuation has found many applications, including low-power displays, (1) variable-focus lenses, (7) thermal switches, (8) electrical switches, (9) energy harvesting, (10) and rheometers. (11,12) As a lab-on-a-chip platform, (13) EWOD has been widely used for applications as diverse as combinatorial synthesis, (14) sample processing, (15,16) enzymelinked immunosorbent assay (ELISA), (17) and cell manipulation.…”

Section: Dielectric Layer For Electrowettingmentioning

confidence: 99%

Counterbalanced Valve Metal Oxide as a Reliable Dielectric Layer for Electrowetting-on-dielectric Devices

Chen¹,

Kim²

2019

Sensors and Materials

View full text Add to dashboard Cite

Valve metal oxide (anodized oxide) is used in a mirrored configuration to serve as selflimiting dielectric layers of electrowetting-on-dielectric (EWOD) devices. Resembling nonpolar electrolytic capacitors, the two opposing metal-dielectric layers always counterbalance each other so that voltages of any polarity can be applied without current flow. By using tantalum pentoxide as the valve metal oxide for experimental evaluation, the mirrored configuration is compared with the usual configuration and further compared with silicon oxide and silicon nitride, which are two dielectric materials commonly used for EWOD. Experiments with a range of applied biases confirm that in a mirrored configuration, one of the two metaldielectric-electrolyte combinations is always reverse-biased to prevent the current leakage, which is the most common mode of failure for the EWOD devices. The utility is demonstrated by manipulating droplets of KCl solution on both the parallel-plate and one-plate EWOD devices.

show abstract

Thermal conductance switching based on the actuation of liquid droplets through the electrowetting on dielectric (EWOD) phenomenon

Cited by 30 publications

References 19 publications

Thermal diodes, regulators, and switches: Physical mechanisms and potential applications

Thermal diodes, regulators, and switches: Physical mechanisms and potential applications

Dynamics of droplet motion induced by Electrowetting

Counterbalanced Valve Metal Oxide as a Reliable Dielectric Layer for Electrowetting-on-dielectric Devices

Contact Info

Product

Resources

About