Packaging method of superfine liquid metal

Abstract

The invention discloses a packaging method of superfine liquid metal. The packaging method comprises the following steps: filling a heat shrink tube with liquid metal by using negative pressure; metal electrodes are inserted into the two ends of the heat shrink tube, and a heat gun is used for enabling the ends of the heat shrink tube to shrink and tightly wrap the metal electrodes; one end of the heat shrink tube is connected with a winding disc, the other end or the middle part of the heat shrink tube is fixedly connected relative to the winding disc, the winding disc is connected to provide stable pulling force, and the heat gun is used for heating and shrinking the heat shrink tube to achieve the target wire diameter. According to the invention, the process for sealing the liquid metal can be effectively simplified, the diameter and the length of the liquid metal wire can be accurately controlled, the wire diameter can be dynamically controlled through heating and stretching, and the liquid metal wire has good sealing performance.

Description

Technical Field

[0001] The invention relates to the field of micro-nano processing technology, and in particular to a packaging method for ultrafine liquid metal. Background Art

[0002] Liquid metals, especially materials such as gallium-indium eutectic alloys, have shown great application potential in flexible electronics, wearable devices, biomedical engineering and microfluidic systems due to their excellent electrical conductivity and fluidity at room temperature. However, the fluidity of liquid metals also poses a challenge to their precise control.

[0003] Among the existing packaging technologies, tubular packaging is a commonly used method. By injecting liquid metal into a pre-prepared tubular structure, the liquid metal can be effectively prevented from leaking and its shape can be maintained. This packaging method has certain advantages, such as relatively intuitive operation and better mechanical protection. However, for liquid metal wires that require extremely fine diameters, the traditional tubular packaging method faces the following major problems: 1. Complex packaging process: To encapsulate extremely fine liquid metal wires, very fine tubes are usually required, which itself increases the difficulty of processing. In addition, precise injection devices and strict sealing measures are required to ensure that the liquid metal can accurately enter the tube without overflowing. The entire process may involve multi-step micromachining technology and highly precise operations, which significantly increases the packaging cost.

[0004] 2. Lack of flexibility: Once the package is completed, it is difficult to make subsequent adjustments to the liquid metal wire, such as changing its length or diameter, using the traditional tubular packaging method. If the wire specifications need to be modified, the entire packaging process often needs to be repeated, which greatly limits its adaptability in practical applications.

[0005] 3. Difficulty in achieving small diameters: Even with complex processes, existing tubular packaging methods make it difficult to ensure that the diameter of liquid metal wires can remain stable at extremely small sizes. Due to the fluidity and surface tension of liquid metal, it is easy for unevenness or leakage to occur during the packaging process, resulting in unstable quality of the final product.

[0006] Although there are some simple tubular packaging methods, such as directly using ordinary plastic tubes or rubber tubes for packaging, these methods can usually only provide thicker wires, which are difficult to meet the needs of miniaturized applications. Summary of the invention

[0007] The technical problem to be solved by the embodiments of the present invention is to provide a method for packaging ultrafine liquid metal, which can prepare extremely fine liquid metal wires with a simple process, and after the preparation is completed, the diameter and length of the wires can be arbitrarily changed within a specified range.

[0008] In order to solve the above technical problems, an embodiment of the present invention provides a method for packaging ultrafine liquid metal, comprising the following steps: S1: Use negative pressure to fill the heat shrink tube with liquid metal; S2: inserting metal electrodes into both ends of the heat shrink tube, and using a hot air gun to shrink the ends of the heat shrink tube to tightly wrap the metal electrodes; S3: Connect one end of the heat shrink tube to the wire winding disc, and fix the other end or the middle part relative to the wire winding disc, so that the wire winding disc connection provides a stable pulling force, and use the hot air gun to heat and shrink the heat shrink tube to achieve the target wire diameter.

[0009] Furthermore, the method further comprises step S4: releasing the tension of the completely stretched and shrunk heat shrinkable tube and then heating and rebounding the tube, thereby performing secondary control on the length and diameter of the heat shrinkable tube.

[0010] Furthermore, the winding disc is connected to the motor and provides a stable pulling force of 0-1 Newton.

[0011] Furthermore, the heating temperature of the hot air gun is 100°C±10°C.

[0012] Furthermore, in S1, a syringe is used to generate negative pressure.

[0013] Furthermore, the original outer layer diameter of the heat shrinkable tube is 1200 microns, the outer layer can be stretched to 350 microns at its thinnest, and the average diameter of the inner liquid metal core part is as low as 126.14 microns.

[0014] Implementing the embodiments of the present invention has the following beneficial effects: 1. Simplify the packaging process: By using ordinary syringes and heat shrink tubes, efficient packaging of liquid metal can be achieved.

[0015] 2. Improve packaging accuracy: By controlling the shrinkage and stretching of the heat shrink tube, the diameter and length of the liquid metal wire can be precisely controlled.

[0016] 3. Good sealing: The two ends of the heat shrink tube of the present invention use pins as electrodes, and excellent sealing can be achieved only by tightening the heat shrink tube itself.

[0017] 4. Realize dynamic adjustment: Through heating and stretching, the length and diameter of the liquid metal wire can be adjusted secondary.

[0018] 5. Ultra-fine packaging diameter: The preparation scheme of the present invention can produce an ultra-fine liquid metal wire with an average diameter of the inner liquid metal core as low as 126.14 microns. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 is a schematic diagram of the present invention using negative pressure to fill the heat shrink tube with liquid metal; Figure 2 It is a schematic diagram of the combination of the metal electrode and the end of the heat shrink tube of the present invention; Figure 3 is a schematic diagram of stretching a heat shrink tube according to the present invention; Figure 4 This is an implementation method of the present invention applied to fingertip pulse wave signal collection; Figure 5 The present invention is applied to the implementation of near field communication; Figure 6 This is a cross-sectional scan of a liquid metal wire of the present invention taken under a scanning electron microscope after being pulled to a limit diameter. DETAILED DESCRIPTION

[0020] In order to make the objectives, technical solutions and advantages of the present invention more clear, the present invention will be further described in detail below with reference to the accompanying drawings.

[0021] A method for packaging ultrafine liquid metal according to an embodiment of the present invention uses a flexible heat shrink tube as a carrier and is implemented in the following manner.

[0022] like Figure 1 As shown in the operation diagram, the interface 1 of the syringe 2 is connected to one end of the heat shrink tube 4, and the other end is placed in a container containing liquid metal 3. The syringe 2 is drawn out to form a negative pressure in the heat shrink tube 4, so that the liquid metal fills the heat shrink tube.

[0023] In the above operation, you can choose to use a heated heat shrink tube 4 to connect with the interface 1 of the syringe 2. The wrapping force generated by the heat shrink tube after heating and shrinking can prevent the liquid metal from flowing out of the heat shrink tube, and no additional adhesive material is required.

[0024] The liquid metal used above is specifically a 50:50 gallium-indium alloy.

[0025] Combination Figure 2 As shown, the metal electrode 5 is inserted into one end of the heat shrink tube 4 , and the end thereof is heated using a hot air gun 6 , so that the end of the heat shrink tube 4 shrinks and tightly wraps the metal electrode 5 .

[0026] The metal electrodes of the liquid metal wire of this embodiment are taken from 2.54 mm pitch pins and have a length of 1 cm.

[0027] like Figure 3 As shown, the heat shrinkable tube filled with liquid metal of the present invention is wound on a stretching and winding device, which includes a clamp 7 and a shell 8 arranged on a workbench, a motor 10 is arranged in the shell 8, the rotating shaft of the motor 10 extends out of the shell 8, and a winding disc 11 is provided.

[0028] One end of the heat shrink tube is fixedly connected to the winding disc, and the other end or the middle part thereof is fixedly clamped on the clip 7. The rotational torque of the motor is controlled by the single chip microcomputer so that the winding disc connection provides a stable pulling force, and a hot air gun is used to uniformly heat and shrink the heat shrink tube to achieve the target wire diameter, thereby forming a thin liquid metal wire 9 after stretching, heating and heat shrinkage.

[0029] When the hot air gun 6 continuously blows out hot air at 100°C ± 10°C from right to left and moves slowly, the original liquid metal wire 4 will be stretched and elongated to become a thinner liquid metal wire 9. At the same time, the wire will become longer due to stretching during heating. By rotating the winding disk 11 connected to the motor in the direction indicated by the arrow, the liquid metal wire can be collected while providing torque.

[0030] By changing the motor torque, the winding disk converts the torque into a stable pulling force of 0-1 Newton. Using different torques to heat and stretch the heat shrink tube can stretch liquid metal core wires of different diameters.

[0031] The original outer diameter of the heat shrink tube is 1200 microns, and the outer layer can be stretched to 350 microns at its thinnest, while the average diameter of the inner liquid metal core part is as low as 126.14 microns, so that liquid metal core wires with an average diameter as low as 126.14 microns can be prepared.

[0032] Length rebound operation: After the fully stretched and shrunk heat shrink tube releases the motor tension, it can be heated again to rebound, so as to achieve secondary dynamic control of the length and diameter of the heat shrink tube, so as to accurately control the stretching length and wire diameter of the heat shrink tube.

[0033] like Figure 4 As shown, use case 1 of the liquid metal wire is a fingertip pulse wave signal acquisition system based on the liquid metal wire, which uses the flexible liquid metal wire 9 of the present invention to connect with the fingertip pulse wave sensor 15 on the glove 14, and fixes the liquid metal wire on the glove by suture 16, which serves as a connecting line to power the fingertip pulse wave sensor 15 and transmit data to the controller 13, and then the controller transmits the waveform data to the display 12 for display.

[0034] like Figure 5 As shown in the use case 2 of the liquid metal wire, the liquid metal wire 9 is connected to a near-field communication chip 17. The spiral antenna made of the liquid metal wire of the present invention can collect and transmit near-field communication signals. A device 18 with a near-field communication identification function can communicate with the system.

[0035] like Figure 6The cross-sectional scan of the liquid metal wire shown in the scanning electron microscope after being pulled to the limit diameter, the central part is liquid metal, the surrounding circle is the wall of the heat shrink tube, and the slightly irregular shape is caused by cutting and sampling.

[0036] The packaging process of the present invention has the following advantages: Simplify the packaging process: Efficient packaging of liquid metal is achieved by using ordinary syringes and heat shrink tubing.

[0037] Improve packaging accuracy: By controlling the shrinkage and stretching of the heat shrink tube, the diameter and length of the liquid metal wire can be precisely controlled.

[0038] Sealing: The two ends of the heat shrink tube of the present invention use pin headers as electrodes, and excellent sealing can be achieved by simply tightening the heat shrink tube itself.

[0039] Realize dynamic adjustment: Through heating and stretching, the length and diameter of the liquid metal wire can be adjusted secondary.

[0040] Ultra-fine packaging diameter: The preparation scheme of the present invention can produce an ultra-fine liquid metal wire with an average diameter of the inner liquid metal core portion as low as 126.14 microns.

[0041] The above disclosure is only a preferred embodiment of the present invention, which certainly cannot be used to limit the scope of the present invention. Therefore, equivalent changes made according to the claims of the present invention are still within the scope of the present invention.

Claims

1. A method for packaging ultrafine liquid metal, characterized in that: The following steps are involved: S1: Use negative pressure to fill the heat shrink tube with liquid metal; S2: inserting metal electrodes into both ends of the heat shrink tube, and using a hot air gun to shrink the ends of the heat shrink tube to tightly wrap the metal electrodes; S3: Connect one end of the heat shrink tube to the wire winding disc, and fix the other end or the middle part relative to the wire winding disc, so that the wire winding disc connection provides a stable pulling force, and use the hot air gun to heat and shrink the heat shrink tube to achieve the target wire diameter.

2. The method for packaging ultrafine liquid metal according to claim 1, characterized in that: The method further comprises step S4: releasing the tension of the completely stretched and shrunk heat shrinkable tube and then heating and rebounding the tube, thereby performing secondary control on the length and diameter of the heat shrinkable tube.

3. The method for packaging ultrafine liquid metal according to claim 2, characterized in that: The cable reel is connected to the motor and provides a stable pulling force of 0-1 Newton.

4. The method for packaging ultrafine liquid metal according to claim 2, characterized in that: The heating temperature of the hot air gun is 100°C±10°C.

5. The method for packaging ultrafine liquid metal according to claim 2, characterized in that: In S1, a syringe is used to generate negative pressure.

6. The method for packaging ultrafine liquid metal according to any one of claims 1 to 5, characterized in that: The original outer diameter of the heat shrinkable tube is 1200 microns, the outer layer can be stretched to 350 microns at its thinnest, and the average diameter of the inner liquid metal core part is as low as 126.14 microns.

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