Rapid electrocapillary deformation of liquid metal with reversible shape retention

Gough, Ryan C.; Morishita, Andy M.; Dang, Jonathan H.; Moorefield, Matthew R.; Shiroma, Wayne A.; Ohta, Aaron T.

doi:10.1186/s40486-015-0017-z

Cited by 66 publications

(42 citation statements)

References 17 publications

(23 reference statements)

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“…For example, it is possible to use oxidative potentials to inject metal into capillaries (by lowering the interfacial tension of the leading meniscus, as shown in Figure 2), and then use reductive potentials to induce the metal to retreat from the capillary (by increasing the interfacial tension of the leading meniscus, as shown in Figure 3) 28,29 . The limits and capabilities of this approach are yet to be fully determined, although injection appears to be slower than withdrawal.…”

Section: Discussionmentioning

confidence: 99%

A Method to Manipulate Surface Tension of a Liquid Metal via Surface Oxidation and Reduction

Eaker

Khan

Dickey

2016

JoVE

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Controlling interfacial tension is an effective method for manipulating the shape, position, and flow of fluids at sub-millimeter length scales, where interfacial tension is a dominant force. A variety of methods exist for controlling the interfacial tension of aqueous and organic liquids on this scale; however, these techniques have limited utility for liquid metals due to their large interfacial tension.Liquid metals can form soft, stretchable, and shape-reconfigurable components in electronic and electromagnetic devices. Although it is possible to manipulate these fluids via mechanical methods (e.g., pumping), electrical methods are easier to miniaturize, control, and implement. However, most electrical techniques have their own constraints: electrowetting-on-dielectric requires large (kV) potentials for modest actuation, electrocapillarity can affect relatively small changes in the interfacial tension, and continuous electrowetting is limited to plugs of the liquid metal in capillaries.Here, we present a method for actuating gallium and gallium-based liquid metal alloys via an electrochemical surface reaction. Controlling the electrochemical potential on the surface of the liquid metal in electrolyte rapidly and reversibly changes the interfacial tension by over two orders of magnitude ( ̴ 500 mN/m to near zero). Furthermore, this method requires only a very modest potential (< 1 V) applied relative to a counter electrode. The resulting change in tension is due primarily to the electrochemical deposition of a surface oxide layer, which acts as a surfactant; removal of the oxide increases the interfacial tension, and vice versa. This technique can be applied in a wide variety of electrolytes and is independent of the substrate on which it rests. Video LinkThe video component of this article can be found at

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Section: Discussionmentioning

confidence: 99%

A Method to Manipulate Surface Tension of a Liquid Metal via Surface Oxidation and Reduction

Eaker

Khan

Dickey

2016

JoVE

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“…Direct electrical actuation of liquid metal is possible through the manipulation of the liquid metal's surface tension through a phenomenon known as electrocapillarity [60]. Various derivatives of electrocapillarity exist, such as electrowetting (EW) [61], electrowetting on dielectric (EWOD) [62], continuous electrowetting (CEW) [52], electrochemical oxide deposition [50], and electrocapillary actuation (ECA) [3]. Among these liquid-metal actuation techniques, only CEW and ECA fulfill the critera of rapid liquid-metal deformation (∼100 mm/s) with a low-voltage (less than 5V) and low-power electrical signal (µW − mW) [3,52].…”

Section: Future Work: Electrical Actuation Of Liquid Metalmentioning

confidence: 99%

“…Various derivatives of electrocapillarity exist, such as electrowetting (EW) [61], electrowetting on dielectric (EWOD) [62], continuous electrowetting (CEW) [52], electrochemical oxide deposition [50], and electrocapillary actuation (ECA) [3]. Among these liquid-metal actuation techniques, only CEW and ECA fulfill the critera of rapid liquid-metal deformation (∼100 mm/s) with a low-voltage (less than 5V) and low-power electrical signal (µW − mW) [3,52]. To deform the liquid metal, ECA can be used by directly biasing the EDL with an external voltage [3].…”

Section: Future Work: Electrical Actuation Of Liquid Metalmentioning

confidence: 99%

Liquid-Metal-Based Reconfigurable Components for RF Front Ends

et al. 2015

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All Rights Reserved AcknowledgmentsI feel that this is a rare opportunity for me to share a bit of candidness and hope to make the most of it. I truly owe the completion of this thesis to many friends and family members and am sorry that I cannot thank you all. hope we can all stay in touch and get a bite and a drink together every once in a while. To leave off I would like to quote Andy Morishita and say "memories are made together" and I will always cherish these past few years we all had. This thesis focuses on the development of liquid-metal-based reconfigurable components for radio-frequency (RF) front ends. Reconfigurable components allow the RF front end to dynamically change key radio parameters such as output power, signal carrier frequency, and bandwidth. These capabilities enable the radio transceiver to adapt to environmental and communication channel changes on the fly, according to programmed protocols and priorities. As a low-loss metallic conductor, the liquid metal Galinstan is well suited for RF applications, and its fluidic nature makes it a natural candidate for reconfigurable architectures. Three liquid-metal based components are described: a frequency-tunable substrate integrated waveguide cavity filter, an electromagnetic bandgap phase shifter, and a frequency-reconfigurable slot antenna. These components are designed, fabricated, and tested and the advantages and disadvantages of using liquid metal are discussed. iv

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“…Gough et al (2015) applied a low voltage or power (1-2 mW) between liquid metal and surrounding electrolyte in a reservoir connected to one or more capillary channels. The geometry of the device had a high aspect ratio (width to height) which enabled a higher ratio of surface area to volume of the liquid metal.…”

Section: Manipulation By External Electric/magnetic Fieldmentioning

confidence: 99%

Gallium-Based Room-Temperature Liquid Metals: Actuation and Manipulation of Droplets and Flows

Majidi

Gritsenko

2017

Front. Mech. Eng.

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Gallium-based room-temperature liquid metals possess extremely valuable properties, such as low toxicity, low vapor pressure, and high thermal and electrical conductivity enabling them to become suitable substitutes for mercury and beyond in wide range of applications. When exposed to air, a native oxide layer forms on the surface of gallium-based liquid metals which mechanically stabilizes the liquid. By removing or reconstructing the oxide skin, shape and state of liquid metal droplets and flows can be manipulated/actuated desirably. This can occur manually or in the presence/absence of a magnetic/electric field. These methods lead to numerous useful applications such as soft electronics, reconfigurable devices, and soft robots. In this mini-review, we summarize the most recent progresses achieved on liquid metal droplet generation and actuation of gallium-based liquid metals with/without an external force.

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Rapid electrocapillary deformation of liquid metal with reversible shape retention

Cited by 66 publications

References 17 publications

A Method to Manipulate Surface Tension of a Liquid Metal via Surface Oxidation and Reduction

A Method to Manipulate Surface Tension of a Liquid Metal via Surface Oxidation and Reduction

Liquid-Metal-Based Reconfigurable Components for RF Front Ends

Gallium-Based Room-Temperature Liquid Metals: Actuation and Manipulation of Droplets and Flows

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