METHODS, SYSTEMS, AND COMPUTER READABLE MEDIA FOR VOLTAGE CONTROLLED RECONFIGURATION OF LIQUID METAL STRUCTURES
Voltage controlled reconfiguration of liquid metal structures by providing an electrolyte in the container. A liquid metal structure is provided in the container and at least partially in contact with the electrolyte. A voltage is applied between the liquid metal structure and the electrolyte to change the shape of the liquid metal structure such that the structure achieves a desired shape for an electrical, optical, mechanical, or thermal application.
This application claims the benefit of U.S. Provisional Patent Application Ser. No. 61/831,597, filed Jun. 5, 2013; the disclosure of which is incorporated herein by reference in its entirety.
GOVERNMENT INTERESTThis invention was made with government support under Grant No. ECCS-0925797 awarded by the National Science Foundation. The government has certain rights in the invention.
TECHNICAL FIELDThe subject matter described herein relates to controlled reconfiguration of liquid metal structures.
BACKGROUNDMercury is liquid at room temperature and atmospheric pressure. Because of the liquid nature of mercury, it is possible to change the configuration or shape of a liquid metal structure formed of mercury through application of mechanical force. However, mercury is highly toxic and therefore unsuitable for applications where the likelihood of exposure to humans is high.
Gallium alloys, like mercury, are liquid at room temperature and atmospheric pressure. Gallium metal is also liquid near room temperature and atmospheric pressure. Unlike mercury, gallium is considered to have low-toxicity. Because of its liquid phase at room temperature and atmospheric pressure and its relative low-toxicity, gallium may be useful for forming reconfigurable electrical, optical, thermal, or mechanical structures, such as filters in optical applications, antennas or wires in electronics applications, heat sinks in thermal applications, or microstructures in mechanical applications. However, one problem with using gallium as the medium for forming a reconfigurable structure is that an oxide skin forms on gallium. This skin causes the metal to stick to most surfaces and results in residue that remains even after a portion of the liquid gallium is moved, for example, from a fluid channel to a reservoir.
Accordingly, there exists a need for improved methods for voltage controlled reconfiguration of liquid metal structures.
SUMMARYThe subject matter described herein relates to voltage controlled reconfiguration of liquid metal structures. According to one exemplary method, a container is provided. An electrolyte is provided in the container. A liquid metal structure is provided in the container and at least partially in contact with the electrolyte. A voltage is applied between the liquid metal structure and the electrolyte to change the shape of the liquid metal structure such that the structure achieves a desired shape for an electrical, mechanical, optical, or thermal application.
A controller for voltage controlled spreading of liquid metal structures may be implemented in hardware, software, firmware, or any combination thereof. As such, the terms “function” or “module” as used herein refer to hardware, which may also include software and/or firmware components, for implementing the feature being described. In one exemplary implementation, the subject matter described herein may be implemented using a computer readable medium having stored thereon computer executable instructions that when executed by the processor of a computer control the computer to perform steps. Exemplary computer readable media suitable for implementing the subject matter described herein include non-transitory computer-readable media, such as disk memory devices, chip memory devices, programmable logic devices, and application specific integrated circuits. In addition, a computer readable medium that implements the subject matter described herein may be located on a single device or computing platform or may be distributed across multiple devices or computing platforms.
The subject matter described herein will now be explained with reference to the accompanying drawings of which:
The subject matter described herein includes methods, systems, and computer readable media for voltage controlled reconfiguration liquid metal structures.
Ga3++3e−→Ga
The result of the reduction of the oxide skin is that the high surface tension of the gallium metal causes the metal to spontaneously withdraw into the reservoir (oval shaped ball on left hand side of
As will be described in more detail below, an oxidative potential may be applied to a liquid metal structure to form a liquid metal structure having a desired shape or to move liquid metal from a reservoir into a microfluidic channel. For example, if, after the liquid metal is in the reservoir as illustrated in
Ga→Ga3++3e−
The gallium combines with oxygen or oxygen containing ions in the electrolyte to form the oxide skin. To maintain charge neutrality, an accompanying reduction reaction occurs at the counter electrode contacting the electrolyte.
In addition, after application of the reductive or oxidative potential is ceased, the liquid metal structure holds its shape. For example,
As used herein, the term “oxidative potential” will be used to refer to the application of a potential to a liquid metal structure that causes oxidation of the liquid metal structure. Thus, the terms “oxidative” and “reductive” are defined with respect to the reactions they cause in the liquid metal structure.
In
The container that holds the liquid metal structure and the electrolyte may be made of any suitable material that is capable of containing gallium and the electrolyte without significant oxidation or reduction of the container. Exemplary container materials suitable for use with the subject matter described herein include glass, Teflon, polystyrene, and tungsten.
In
In
An oxidation reaction occurs on the surface of the gallium metal structure in contact with the electrolyte to form an oxide skin. It is believed that the spreading of the gallium metal occurs when the capacitive energy formed by a capacitor in which the gallium metal is one conductor, the oxide skin is the insulator, and the electrolyte as the other conductor exceeds the surface tension of the gallium structure. When the negative electrode is moved away from the original liquid metal structure, the oxide skin forms around the liquid gallium as it is drawn from its original position. As illustrated in
In
In
According to another aspect of the subject matter described herein, an oxidative potential may be used to cause droplets of a liquid metal to form fibers, as illustrated in
It will be understood that various details of the presently disclosed subject matter may be changed without departing from the scope of the presently disclosed subject matter. Furthermore, the foregoing description is for the purpose of illustration only, and not for the purpose of limitation.
Claims
1. A method for voltage controlled reconfiguration of a liquid metal structure, the method comprising:
- providing a container;
- providing an electrolyte in the container;
- providing a liquid metal structure in the container and at least partially in contact with the electrolyte; and
- applying a voltage between the liquid metal structure and the electrolyte to change the shape of the liquid metal structure such that the structure achieves a desired shape.
2. The method of claim 1 wherein the container defines an elongate fluid channel and a reservoir connected to the fluid channel.
3. The method of claim 2 wherein applying a voltage between the liquid metal structure and the electrolyte includes applying a reductive potential to the liquid metal structure to electrochemically reduce an oxide skin of the liquid metal structure and cause at least a portion of the liquid metal structure to withdraw from the fluid channel.
4. The method of claim 2 wherein applying a voltage between the liquid metal structure and the electrolyte includes applying an oxidative potential to the liquid metal structure to form an oxide skin around the liquid metal structure and cause the at least a portion of the liquid metal structure to move from the reservoir into the fluid channel.
5. The method of claim 1 wherein the container defines a plurality of segments, each of which includes a portion of the liquid metal structure and each of which is coupled to the electrolyte, wherein applying the voltage includes applying a reductive potential to the liquid metal structure in one of the segments to selectively withdraw the liquid metal structure portions from the two segments.
6. The method of claim 1 wherein the container defines a pool for holding the electrolyte and wherein applying a voltage between the liquid metal structure and the electrolyte includes applying a first electrode to the liquid metal structure, applying a second electrode to the electrolyte in proximity to the liquid metal structure, applying an oxidative potential to the liquid metal structure through the first electrode, and moving the second electrode while maintaining contact with the electrolyte to oxidize at least a portion of the liquid metal structure and form a desired shape of the liquid metal structure within the container.
7. The method of claim 1 wherein the container comprises a first container for holding the electrolyte and a second container for holding the liquid metal structure and wherein applying a voltage between the liquid metal structure and the electrolyte includes applying an oxidative potential to the liquid metal structure to move the liquid metal structure from the second container into the first container and form a wire in the first container.
8. The method of claim 1 wherein the container includes a first chamber for holding the electrolyte and a second chamber for holding the liquid metal structure, the first and second chambers being electrically coupled to each other via the electrolyte, and wherein applying the voltage between the liquid metal structure and the electrolyte includes applying a first electrode to the electrolyte, applying a second electrode to the liquid metal structure, and applying an oxidative potential to the liquid metal structure to move the liquid metal structure from the second container.
9. The method of claim 1 wherein the liquid metal structure is immersed within the electrolyte and wherein applying a voltage between the liquid metal structure and the electrolyte includes applying an oxidative potential to the liquid metal structure to spread the liquid metal structure along a surface of the container.
10. The method of claim 1 wherein the structure includes one of a wire, an interconnect, and an antenna.
11. The method of claim 1 wherein the structure includes a mechanical, optical, or thermal structure.
12. The method of claim 1 wherein the liquid metal structure comprises liquid gallium or a liquid gallium alloy.
13. The method of claim 1 comprising ceasing application of the voltage between the liquid metal structure and the electrolyte when the liquid metal structure has formed a desired shape.
14. The method of claim 1 wherein the liquid metal structure comprises a fiber.
15. A method for manufacturing a self-healing electrical structure, the method comprising:
- providing a liquid metal structure comprising a liquid metal material having a liquid metal core and an oxide skin formed around the liquid metal core; and
- encapsulating the liquid metal structure in a self-healing polymer surrounding the oxide skin of the liquid metal structure.
16. A system for voltage control reconfiguration of a liquid metal structure in a fluid channel, the method comprising:
- a container;
- an electrolyte located and at least partially in contact with the electrolyte in the container;
- a liquid metal structure located in the container; and
- a controlled voltage source configured to apply an electrical stimulus to the liquid metal structure to change the shape of the liquid metal structure such that the structure achieves a desired shape.
17. The system of claim 16 wherein the container defines an elongate fluid channel and a reservoir connected to the fluid channel.
18. The system of claim 17 wherein the controlled voltage source is configured to apply a reductive potential to the liquid metal structure to electrochemically reduce an oxide skin of the liquid metal structure and cause at least a portion of the liquid metal structure to withdraw from the fluid channel.
19. The system of claim 17 wherein the controlled voltage source is configured to apply an oxidative potential to the liquid metal structure to form an oxide skin around the liquid metal structure and cause the at least a portion of the liquid metal structure to move from the reservoir into the fluid channel.
20. The system of claim 16 wherein the container defines a plurality of segments, each of which includes a portion of the liquid metal structure and each of which is coupled to the electrolyte, wherein the controlled voltage source is configured to apply a reductive potential to the liquid metal structure in one of the segments to selectively withdraw the liquid metal structure portions from the two segments.
21. The system of claim 16 wherein the container defines a pool for holding the electrolyte and wherein the controlled voltage source includes a first electrode for contacting the liquid metal structure, a second electrode for contacting the electrolyte in proximity to the liquid metal structure, and wherein the controlled voltage source is configured to apply an oxidative potential to the liquid metal structure through the first electrode, and the second electrode is configured to move while maintaining contact with the electrolyte to oxidize at least a portion of the liquid metal structure and form a desired shape of the liquid metal structure within the container.
22. The system of claim 16 wherein the container comprises a first container for holding the electrolyte and a second container for holding the liquid metal structure and wherein the controlled voltage source is configured to apply an oxidative potential to the liquid metal structure to move the liquid metal structure from the second container into the first container and form a wire in the first container.
23. The system of claim 16 wherein the container includes a first chamber for holding the electrolyte and a second chamber for holding the liquid metal structure, the first and second chambers being electrically coupled to each other via the electrolyte, and wherein the controlled voltage source includes a first electrode for contacting the electrolyte, a second electrode for contacting the liquid metal structure, and wherein the controlled voltage source is configured to apply an oxidative potential to the liquid metal structure to move the liquid metal structure from the second container.
24. The system of claim 16 wherein the liquid metal structure is immersed within the electrolyte and wherein the controlled voltage source is configured to apply an oxidative potential to the liquid metal structure to spread the liquid metal structure along a surface of the container.
25. The system of claim 16 wherein the liquid metal structure comprises a fiber.
26. The system of claim 16 wherein the structure includes one of a wire, an interconnect, and an antenna.
27. The system of claim 16 wherein the structure includes a mechanical, optical, or thermal structure, and the property comprises a desired mechanical, optical, or thermal property.
28. The system of claim 16 wherein the liquid metal structure comprises liquid gallium or a gallium alloy.
29. The system of claim 16 wherein the controlled voltage source is configured to cease application of the voltage when a desired shape of the liquid metal structure is achieved.
30. A self-healing electrical structure:
- a liquid metal conductive structure comprising a liquid metal material having a liquid metal core and an oxide skin formed around the liquid metal core; and
- a self-healing polymer surrounding the oxide skin of the liquid metal structure.
Type: Application
Filed: Jun 5, 2014
Publication Date: May 5, 2016
Inventors: Michael David Dickey (Raleigh, NC), Collin Eaker (Raleigh, NC), Mohammad Rashed Khan (Raleigh, NC)
Application Number: 14/896,602