Liquid metal microrobot and manufacturing method thereof

Abstract

The application discloses a liquid metal micro-robot and a manufacturing method thereof. The liquid metal micro-robot comprises a foam ball, an adhesive layer is uniformly arranged on the outer surface of the foam ball and adhered to the foam ball, a metal powder layer is arranged on the adhesive layer and is composed of metal powder, a liquid metal alloy layer is coated on the metal powder layer, and an intermetallic compound is formed between the liquid metal alloy layer and the metal powder layer. The liquid metal micro-robot is light in weight, is low in density and can realize free movement of the liquid metal micro-robot in an electrolyte solution through movement and accurate control of an electrode.

Description

Technical Field

[0001] This invention belongs to the field of materials and relates to a liquid metal microrobot and its fabrication method. Background Technology

[0002] Gallium-based room-temperature liquid metals, as a novel functional material that has emerged in recent years, have attracted considerable attention. Their excellent conductivity, mobility, and deformability have led to exploration of applications in many fields. Many applications are based on the precise control and actuation of liquid metals, with common actuation methods including electric fields, magnetic fields, chemical and electrochemical reactions, and light. Currently, most methods for actuating liquid metals using magnetic fields involve modifying the surface of the liquid metal with ferromagnetic materials.

[0003] Due to the fluidity and gravity of liquid metals, pure liquid metals and magnetic liquid metals mostly move in a two-dimensional plane, thus making it impossible for liquid metals to autonomously complete three-dimensional movements. Summary of the Invention

[0004] The purpose of this invention is to provide a liquid metal microrobot capable of three-dimensional motion and its manufacturing method.

[0005] The technical solution adopted by this invention to solve its technical problem is:

[0006] A liquid metal microrobot includes a foam ball, an adhesive layer uniformly disposed on the outer surface of the foam ball and bonded to the foam ball, a metal powder layer composed of metal powder disposed on the adhesive layer, a liquid metal alloy layer coated on the metal powder layer, and an intermetallic compound formed between the liquid metal alloy layer and the metal powder layer.

[0007] A method for fabricating a liquid metal microrobot includes the following steps:

[0008] S1, Prepare the foam balls;

[0009] S2, Apply a layer of adhesive evenly to the surface of the foam ball to form the adhesive layer;

[0010] S3, metal powder is sprinkled onto the adhesive to uniformly coat the surface of the adhesive layer to form the metal powder layer;

[0011] S4, add acid solution to the metal powder layer and let stand for 10 seconds;

[0012] S5, a liquid metal alloy is coated on the metal powder layer, so that the interface between the liquid metal alloy and the metal powder forms the intermetallic compound layer.

[0013] Preferably, the diameter of the foam ball is 5 mm.

[0014] Preferably, the adhesive is a polyacrylate pressure-sensitive adhesive.

[0015] Preferably, the metal powder is copper powder.

[0016] Preferably, the liquid metal alloy is a gallium-based liquid metal alloy.

[0017] Preferably, the acid solution is a hydrochloric acid solution.

[0018] Preferably, its density is 0.99–1.17 g / cm³. 3 .

[0019] The beneficial effects of this invention are: a lightweight liquid metal microrobot is made using foam balls, which has a lower density than other liquid metal robots and can achieve free movement in an electrolyte solution through the movement and precise control of electrodes. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of the liquid metal microrobot of the present invention;

[0021] Figure 2 This is a schematic diagram of the liquid metal microrobot of the present invention in a sodium hydroxide solution;

[0022] Figure 3 This invention is in Figure 2 A diagram illustrating upward movement;

[0023] Figure 4 This invention is in Figure 2 A schematic diagram of downward movement;

[0024] Figure 5 This is a schematic diagram of the structure of the present invention, which forms an oxide layer through oxidation in air;

[0025] Figure 6 yes Figure 3 Schematic diagram of the structure after removing the oxide layer;

[0026] Figure 7 This is a schematic diagram of the structure of the double layer formed in sodium hydroxide solution according to the present invention;

[0027] Figure 8 yes Figure 7 A schematic diagram of the charge redistribution structure; Detailed Implementation

[0028] To enable those skilled in the art to better understand the technical solutions of this invention, the technical solutions of this invention will be clearly and completely described below with reference to the relevant accompanying drawings in the embodiments of this invention. Obviously, the described embodiments are only some embodiments of this invention, and not all embodiments.

[0029] like Figures 1 to 8 As shown, this invention provides a liquid metal microrobot, comprising a foam ball 10, with an adhesive layer 12, a metal powder layer 14, and a liquid metal alloy layer 16 sequentially disposed on the exterior of the foam ball 10. The outer surface of the foam ball 10 is bonded to the adhesive layer 12, which is composed of an adhesive. A metal powder layer 14, composed of metal powder, is disposed on the adhesive layer 12, and the liquid metal alloy layer 16 is coated on the metal powder layer 14. An intermetallic compound is formed between the liquid metal alloy layer 16 and the metal powder layer 14. This invention retains the properties of liquid metal, such as excellent motion and deformation behavior. The microrobot made using the lightweight foam ball 10 and the liquid metal alloy can be tracked and controlled in three-dimensional space via electrodes, while maintaining the properties of pure liquid metal.

[0030] This invention also provides a method for fabricating a liquid metal microrobot, comprising the following steps:

[0031] S1, Prepare foam balls 10;

[0032] S2, Apply a layer of adhesive evenly to the surface of the foam ball 10 to form an adhesive layer 12;

[0033] S3, sprinkle metal powder on the adhesive, and roll the foam ball 10 to coat the metal powder evenly on the surface of the adhesive layer 12 to form a metal powder layer 14.

[0034] S4, add acid solution to metal powder layer 14 and let stand for 10 seconds;

[0035] S5, a liquid metal alloy is coated on the metal powder layer 14, so that an intermetallic compound layer is formed at the interface between the liquid metal alloy and the metal powder.

[0036] The above process is carried out at room temperature.

[0037] In a preferred embodiment of the present invention, the foam ball 10 has a diameter of approximately 5 mm and a weight of approximately 2.5 mg. A polyacrylate pressure-sensitive adhesive is coated on the surface of the foam ball 10, and copper powder is sprinkled on the polyacrylate pressure-sensitive adhesive. Due to the high viscosity of the adhesive, the copper powder can be firmly bonded. A concentrated hydrochloric acid solution is added to the copper powder and allowed to stand for 10 seconds. A gallium-based liquid metal alloy with a volume of approximately 25 μl is coated on the copper powder layer. Since a Cu-Ga intermetallic compound is formed at the interface between the gallium-based liquid metal alloy and the copper powder in the acid solution, the gallium-based liquid metal alloy exhibits good wetting behavior on the copper powder.

[0038] Since pure liquid metal alloys cannot suspend and perform 3D motion, this invention utilizes foam balls 10 to lighten the liquid metal microrobot, with a density ranging from 0.99 to 1.17 g / cm³. 3 Its density is 6.44 g / cm³, which is greater than that of a pure liquid metal alloy. 3 It needs to be much smaller so that it can be tracked via electrodes and its movement controlled in three-dimensional space.

[0039] The metal powder selected in this invention is copper powder, and the liquid metal alloy is gallium-based liquid metal alloy. The reason is that a CuGa2 compound will be formed between the copper powder layer, i.e., the metal powder layer 14, and the liquid metal alloy layer 16. This compound is a bidirectional conductive film, which is beneficial for the liquid metal robot to be better controlled by the electric field. Other metal powders and gallium are difficult to form conductive films.

[0040] When liquid metal alloys are exposed to air, gallium, the main metallic element in the liquid metal, is oxidized by oxygen and forms a thin oxide layer on the surface of the liquid metal, mainly composed of Ga₂O₃. This significantly restricts the fluidity of the liquid metal. Figure 5 As shown. When a liquid metal alloy is placed in an electrolyte such as sodium hydroxide solution, taking sodium hydroxide solution as an example, the following reaction will occur:

[0041] 2Ga + 6OH _ →Ga₂O₃ + 3H₂O + 6e _

[0042] Ga₂O₃ + 2NaOH + 3H₂O → 2NaGa(OH)₄

[0043] The wrinkled oxide layer on the surface of the oxidized liquid metal alloy will be chemically removed, such as... Figure 6 As shown, the present invention maintains a spherical shape in sodium hydroxide solution.

[0044] According to the principle of electric double layer, when a liquid metal alloy is in an electrolyte environment, as shown in the above chemical reaction formula, Ga reacts to generate anions, thus giving the surface of the gallium-based liquid metal alloy a negative charge. Therefore, an electric double layer will be generated at the interface between the liquid metal alloy and electrolytes such as sodium hydroxide. Figure 7 As shown.

[0045] Due to the high conductivity of liquid metal alloys, the potential throughout the entire liquid metal alloy must be approximately uniform. Conversely, electrolytes have finite conductivity; therefore, if a voltage is applied, a potential gradient is generated along the electrode direction, which alters the potential difference along the surface of the liquid metal alloy. This will cause a phenomenon similar to... Figure 8 The diagram illustrates the redistribution of surface charge on a liquid metal alloy. The surface tension between the liquid metal alloy and the electrolyte solution depends on the potential difference at that point.

[0046] The magnitude of this tension can be described by the Lippman equation: The left side of the equation represents the interfacial tension between the liquid metal and the electrolyte solution, c is the double-layer capacitance per unit area, and V is the potential difference across the double layer, which is the maximum interfacial tension when V=0. Therefore, when a non-uniform electric field is applied, the surface tension becomes non-uniform, leading to a pressure difference. This breaks the symmetry of the liquid metal system, resulting in displacement, known as the Marangoni effect. The liquid with higher surface tension exerts a stronger pull on the surrounding liquid with lower surface tension, creating a surface tension gradient; causing the liquid to flow from the direction of lower surface tension to the direction of higher surface tension.

[0047] like Figures 2 to 3 As shown, the liquid metal 3D microrobot of this invention is placed in a container filled with sodium hydroxide solution, and a positively charged copper wire is used to pull the liquid metal 3D moving microrobot upwards. The liquid metal microrobot rises to the surface of the sodium hydroxide solution within 5 seconds; after changing direction, as... Figure 4 As shown, copper wires enable a liquid metal microrobot to sink in 7.4 seconds, thus achieving electric drive for the liquid metal 3D microrobot.

[0048] This invention utilizes foam balls to fabricate a lightweight liquid metal microrobot. Compared to other liquid metal robots, it has a lower density and can easily achieve three-dimensional movement in an electrolyte solution. Furthermore, by precisely controlling the movement of the positive electrode, the liquid metal 3D moving microrobot can achieve free movement within the electrolyte solution.

[0049] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the invention can be implemented in other specific forms without departing from its spirit or essential characteristics. Therefore, the embodiments should be considered in all respects as exemplary and non-limiting, and the scope of the invention is defined by the appended claims rather than the foregoing description. Thus, all variations falling within the meaning and scope of equivalents of the claims are intended to be embraced within the invention. No reference numerals in the claims should be construed as limiting the scope of the claims.

[0050] Furthermore, it should be understood that although this specification describes embodiments, not every embodiment contains only one independent technical solution. This narrative style is merely for clarity. Those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

Claims

1. A method for fabricating a liquid metal microrobot, characterized in that, Includes the following steps: S1, Prepare foam balls; S2, Apply a layer of adhesive evenly to the surface of the foam ball to form an adhesive layer; S3, metal powder is sprinkled onto the adhesive to uniformly coat the surface of the adhesive layer to form a metal powder layer; S4, add acid solution to the metal powder layer and let stand for 10 seconds; S5, a liquid metal alloy is coated on the metal powder layer, so that an intermetallic compound layer is formed at the interface between the liquid metal alloy and the metal powder. The metal powder is copper powder; the liquid metal alloy is gallium-based liquid metal alloy; and the density of the liquid metal microrobot is 0.99–1.17 g / cm³.

2. The method for fabricating a liquid metal microrobot according to claim 1, characterized in that: The diameter of the foam ball is 5 mm.

3. The method for fabricating a liquid metal microrobot according to claim 1, characterized in that: The adhesive is a polyacrylate pressure-sensitive adhesive.

4. The method for fabricating a liquid metal microrobot according to claim 1, characterized in that: The acid solution is a hydrochloric acid solution.

5. A liquid metal microrobot, manufactured by the method described in any one of claims 1-4, characterized in that: The liquid metal microrobot includes a foam ball, on the outer surface of which an adhesive layer is uniformly disposed to adhere to the foam ball. A metal powder layer composed of metal powder is disposed on the adhesive layer. A liquid metal alloy layer is coated on the metal powder layer. An intermetallic compound is formed between the liquid metal alloy layer and the metal powder layer.

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