Apparatus for preparing liquid metal microfilaments and preparation method thereof

Abstract

This invention relates to an apparatus for preparing liquid metal microfilaments, comprising a water tank, inside which are fixed tweezers and movable tweezers. The movable tweezers are driven by an electric mechanism to reciprocate along the stretching direction of the liquid metal microfilaments. A temperature control component is provided on the water tank. This invention has a simple structure, good processability, and can efficiently prepare liquid metal microfilaments with a diameter of less than 100 μm that have good stability and high repeatability.

Description

Technical Field

[0001] This invention relates to an apparatus and a method for preparing liquid metal microfilaments, belonging to the field of micro-nano manufacturing. Background Technology

[0002] Liquid metals, with their excellent conductivity, fluidity, and good biocompatibility, hold great promise for applications in neural electrodes and flexible electronics. Common neural electrodes include planar and microfilament forms, with microfilament electrodes having a small diameter, which helps reduce tissue damage during implantation. Electrodes fabricated using liquid metals offer the advantages of flexibility and stretchability, which helps reduce mechanical damage to nerve tissue during long-term implantation and improves the reliability of the electrodes during use.

[0003] Currently, the main methods for preparing liquid metal microfilament electrodes include microfluidic control, spinning, and 3D printing. In microfluidic control, the alignment error between the upper and lower molds is difficult to control, and the microtunnels are easily blocked by residual powder or air bubbles in the liquid metal. In spinning, the polymer shell often forms slowly and lacks sufficient mechanical strength; furthermore, the microfilament diameter is affected by multiple factors such as spinneret speed, polymer concentration, and electrolyte pH, and cannot be adjusted solely by changing the nozzle diameter. 3D printing produces patterns whose quality is highly dependent on printing parameters, and the maintenance cost of the printing equipment is very high. In summary, while all the above methods can produce microfilaments, they suffer from instability during the preparation process and high equipment requirements.

[0004] Fine liquid metal microfilaments with diameters less than 100 μm can be prepared by dip-coating an insulating layer and stretching, offering the advantage of a simple process. Furthermore, liquid metal microfilaments of different diameters can be obtained by controlling the stretching ratio. Simultaneously, the dip-coated polyurethane shell can be stretched at room temperature before complete curing, eliminating the need for high-temperature heating of the polyurethane shell. Nevertheless, currently, there is a lack of equipment for the stable, large-scale preparation of liquid metal microfilaments.

[0005] To address this problem, the present invention proposes an apparatus for preparing liquid metal microfilaments using dip coating and stretching methods. Summary of the Invention

[0006] In view of the shortcomings of the prior art, the technical problem to be solved by the present invention is to provide an apparatus for preparing liquid metal microfilaments and a method thereof.

[0007] To solve the above-mentioned technical problems, the technical solution of the present invention is: an apparatus for preparing liquid metal microfilaments, comprising a water tank, wherein fixed tweezers and movable tweezers are arranged inside the water tank, the movable tweezers are driven by an electric mechanism to reciprocate along the stretching direction of the liquid metal microfilaments, and a temperature control component is provided on the water tank.

[0008] Preferably, the water tank is a long, narrow tank with its opening located at the top.

[0009] Preferably, the temperature control component includes a water inlet and a drain outlet, wherein a water inlet ball valve is provided on the water inlet and a drain ball valve is provided on the drain outlet.

[0010] Preferably, the temperature control component includes a cooling element and a heating element, which are disposed at the bottom of the inner tank of the water tank.

[0011] Preferably, the electric mechanism employs a ball screw pair driven by a stepper motor.

[0012] Preferably, the ball screw assembly includes a base, on which a ball screw is mounted via a bearing and a bearing seat. One end of the ball screw is connected to the output shaft of a stepper motor via a coupling. A ball nut is screwed onto the ball screw, and a movable tweezers mounting seat is fixedly connected to the ball nut. A slider-rail moving pair is connected between the movable tweezers mounting seat and the base.

[0013] Preferably, the slider-rail moving pair includes a slide rail fixedly connected to the base, a slider is provided on the slide rail, and the slider is fixedly connected to the movable tweezers mounting base.

[0014] Preferably, the movable tweezers are fixedly connected to the movable tweezers mounting base, the fixed tweezers are fixedly connected to the fixed tweezers mounting base, and the fixed tweezers mounting base is fixedly connected to the bearing seat.

[0015] Preferably, the gripping openings of both the fixed tweezers and the movable tweezers extend downwards into the interior of the water tank.

[0016] A method for preparing an apparatus for preparing liquid metal microfilaments comprises the following steps:

[0017] S1. Pure gallium with a melting point of 29.8℃ is injected into a silicone tube with an inner diameter of D1 and a length of L1 and frozen solidified. The silicone tube is cut open with a scalpel blade to obtain a liquid metal bare wire with a diameter of D1 and a length of L1.

[0018] S2. For a liquid metal bare wire with a diameter of D1, a polyurethane shell is coated by dipping it in a PU-DMF solution of concentration C at a speed of V1.

[0019] S3. Clamp both ends of the coated liquid metal wire with a diameter of D1 onto the fixed tweezers and the movable tweezers, respectively.

[0020] S4. Pour T1 warm water into the water tank until it covers the liquid metal wire with diameter D1;

[0021] S5. After the liquid metal wire with diameter D1 melts, the electric mechanism is activated, and the movable tweezers mounting base begins to move at a speed of V2, according to the formula... The volume of the microfilament remains unchanged before and after stretching, from By stretching it to N times its original length, a liquid metal microwire with a diameter of D2 can be obtained;

[0022] S6. Adjust the water temperature using the temperature control component to solidify the drawn liquid metal microwires;

[0023] S7. After the thinned liquid metal microwire solidifies, remove the microwire and dissolve the polyurethane shell on the surface with tetrahydrofuran to obtain a thinned liquid metal bare wire with a diameter D2.

[0024] Compared with existing technologies, the present invention has the following advantages: the apparatus for preparing liquid metal microfilaments can efficiently prepare liquid metal microfilaments with a diameter of less than 100 μm that have good stability and high repeatability. It has a simple structure, good processability, and the experimental conditions only require melting the liquid metal in warm water, without the need for high-temperature heating.

[0025] The present invention will now be described in further detail with reference to the accompanying drawings and specific embodiments. Attached Figure Description

[0026] Figure 1 This is a schematic diagram of the structure of Embodiment 1 of the present invention.

[0027] Figure 2 This is a schematic diagram of the structure of Embodiment 2 of the present invention.

[0028] Figure 3 This is a schematic diagram of the structure of fixed / movable tweezers.

[0029] Figure 4 This is a schematic diagram of the "dipping-coating-stretching" process. Detailed Implementation

[0030] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0031] It should be noted that the following detailed descriptions are exemplary and intended to provide further explanation of this application. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains.

[0032] It should be noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the exemplary embodiments according to this application. As used herein, the singular form is intended to include the plural form as well, unless the context clearly indicates otherwise. Furthermore, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0033] like Figure 1 , 4 As shown, this embodiment 1 provides an apparatus for preparing liquid metal microfilaments, including a water tank 1, with fixed tweezers 2 and movable tweezers 3 arranged inside the water tank. The movable tweezers are driven by an electric mechanism 4 to reciprocate along the stretching direction of the liquid metal microfilaments. A temperature control component is provided on the water tank.

[0034] In Embodiment 1 of the present invention, the water tank is a long strip-shaped tank with its opening located at the top of the tank.

[0035] In Embodiment 1 of the present invention, the electric mechanism employs a ball screw assembly driven by a stepper motor 5. A controller 21 is electrically connected to the stepper motor and is used to control the start, stop, and speed changes of the stepper motor.

[0036] In Embodiment 1 of the present invention, the fixed tweezers and the movable tweezers need to be at the same horizontal height.

[0037] In Embodiment 1 of the present invention, the ball screw assembly includes a base 6, on which a ball screw 8 is mounted via a bearing and a bearing seat 7. One end of the ball screw is connected to the output shaft of a stepper motor via a coupling 9. A ball nut 10 is screwed onto the ball screw, and a movable tweezers mounting seat 11 is fixedly connected to the ball nut. A slider slide rail moving pair is connected between the movable tweezers mounting seat and the base.

[0038] In Embodiment 1 of the present invention, two infrared limiters 20 are installed at both ends of one side of the base to sense and limit the movement of the movable tweezers mounting base, preventing the movable tweezers mounting base from moving too far and causing a collision.

[0039] In Embodiment 1 of the present invention, the slider-rail moving pair includes a slide rail 12 fixedly connected to the base, a slider 13 is provided on the slide rail, and the slider is fixedly connected to the movable tweezers mounting base.

[0040] In Embodiment 1 of the present invention, the movable tweezers are fixedly connected to the movable tweezers mounting base, the fixed tweezers are fixedly connected to the fixed tweezers mounting base 14, and the fixed tweezers mounting base is fixedly connected to the bearing seat.

[0041] In Embodiment 1 of the present invention, the temperature control component includes a water inlet and a drain outlet. A water inlet ball valve 15 is provided on the water inlet, and a drain outlet ball valve 16 is provided on the drain outlet.

[0042] In Embodiment 1 of the present invention, the clamping openings of both the fixed tweezers and the movable tweezers extend downwards into the interior of the water tank.

[0043] like Figure 2 , 4 As shown, in Embodiment 2 of the present invention, unlike Embodiment 1, the temperature control component includes a cooling element 17 and a heating element 18, which are disposed at the bottom of the inner tank of the water tank. A temperature sensor 19 is installed on the side of the water tank.

[0044] A method for preparing an apparatus for preparing liquid metal microfilaments comprises the following steps:

[0045] S1. Pure gallium with a melting point of 29.8℃ is injected into a silicone tube with an inner diameter of D1 and a length of L1 and frozen solidified. The silicone tube is cut open with a scalpel blade to obtain a liquid metal bare wire with a diameter of D1 and a length of L1.

[0046] S2. For a liquid metal bare wire with a diameter of D1, a polyurethane shell is coated by dipping it in a PU-DMF solution of concentration C at a speed of V1.

[0047] S3. Clamp both ends of the coated liquid metal wire with a diameter of D1 onto the fixed tweezers and the movable tweezers, respectively.

[0048] S4. Pour T1 warm water into the water tank until it covers the liquid metal wire with diameter D1;

[0049] S5. After the liquid metal wire with diameter D1 melts, the electric mechanism is activated, and the movable tweezers mounting base begins to move at a speed of V2, according to the formula... The volume of the microfilament remains unchanged before and after stretching, from By stretching it to N times its original length, a liquid metal microwire with a diameter of D2 can be obtained;

[0050] S6. Adjust the water temperature using the temperature control component to solidify the drawn liquid metal microwires;

[0051] S7. After the thinned liquid metal microwire solidifies, remove the microwire and dissolve the polyurethane shell on the surface with tetrahydrofuran to obtain a thinned liquid metal bare wire with a diameter D2.

[0052] In S1, the inner diameter D1 of the silicone tube can be 200–500 μm, and the length L1 can be 1–6 cm. The concentration C of the polyurethane (PU)-N,N-dimethylformamide (DMF) solution can be 10%–30%, and the dipping speed V1 can be 10–100 mm / min. In S4, the water temperature T1 can be 33–40℃. In S5, the moving speed V2 of the movable tweezers mounting base can be 5–20 mm / min, the microfilament diameter D2 is the required diameter, and the stretching ratio is... In S6, the cool water temperature T2 can be taken as 0~20℃.

[0053] Specific implementation process:

[0054] Example 1:

[0055] S1. Pure gallium with a melting point of 29.8℃ is injected into a silicone tube with an inner diameter of 300μm and frozen solidified. The silicone tube is cut open with a scalpel to obtain a liquid metal bare wire with a diameter of 300μm.

[0056] S2. For a 300μm diameter liquid metal bare wire, a polyurethane shell is coated by dipping it into a 20% PU-DMF solution at a speed of 50mm / min.

[0057] S3. Clamp the two ends of the 300μm diameter liquid metal wire after dipping and coating onto the fixed tweezers and the movable tweezers respectively;

[0058] S4. Pour warm water at 33-40℃ into the water tank until it covers the liquid metal wire with a diameter of 300μm;

[0059] S5. After the 300μm diameter liquid metal wire melts, the electric mechanism is activated. The movable tweezers mounting base begins to move at a speed of 10mm / min, according to the formula... The volume of the microfilament remains unchanged before and after stretching, from By stretching it to nine times its original length, a liquid metal microwire with a diameter of 100 μm can be obtained;

[0060] S6. Open the water injection ball valve and the drain ball valve to drain the warm water and inject the cold water. By adjusting the water temperature, the thinned liquid metal filaments will solidify.

[0061] S7. After the thinned liquid metal microwire solidifies, remove the microwire and dissolve the polyurethane shell on the surface with tetrahydrofuran to obtain a thinned bare liquid metal wire with a diameter of 100μm.

[0062] Example 2:

[0063] S1. Pure gallium with a melting point of 29.8℃ is injected into a silicone tube with an inner diameter of 300μm and frozen solidified. The silicone tube is cut open with a scalpel to obtain a liquid metal bare wire with a diameter of 300μm.

[0064] S2. For a 300μm diameter liquid metal bare wire, a polyurethane shell is coated by dipping it into a 20% PU-DMF solution at a speed of 50mm / min.

[0065] S3. Clamp the two ends of the 300μm diameter liquid metal wire after dipping and coating onto the fixed tweezers and the movable tweezers respectively;

[0066] S4. Turn on the heating element to raise the water temperature to 33-40℃. At this time, the 300μm diameter liquid metal wire begins to melt.

[0067] S5. After the 300μm diameter liquid metal wire melts, turn off the heating element, start the electric mechanism, and the movable tweezers mounting base will begin to move at a speed of 10mm / min, according to the formula... The volume of the microfilament remains unchanged before and after stretching, from By stretching it to nine times its original length, a liquid metal microwire with a diameter of 100 μm can be obtained;

[0068] S6. Turn on the cooling plate to lower the water temperature to below 20°C until the drawn liquid metal filaments solidify.

[0069] S7. After the thinned liquid metal microwire solidifies, remove the microwire and dissolve the polyurethane shell on the surface with tetrahydrofuran to obtain a thinned bare liquid metal wire with a diameter of 100μm.

[0070] This invention has a simple structure, good processability, and only requires warm water to melt liquid metal for experimental conditions, without the need for high-temperature heating. This invention can be based on the formula... Microfilaments of different diameters can be obtained by changing the stretching length. This has the potential to be developed into continuous industrial production.

[0071] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention in any other way. Any person skilled in the art may make changes or modifications to the above-disclosed technical content to create equivalent embodiments. However, any simple modifications, equivalent changes, and modifications made to the above embodiments based on the technical essence of the present invention without departing from the scope of the present invention shall still fall within the protection scope of the present invention.

Claims

1. An apparatus for preparing liquid metal microfilaments, characterized in that: The device includes a water tank, inside which are installed fixed and movable tweezers. The movable tweezers are driven by an electric mechanism to reciprocate along the stretching direction of liquid metal microfilaments. A temperature control component is installed on the water tank. The water tank is a long, narrow tank with its opening located at the top. The temperature control component includes a water inlet and a water outlet. The water inlet is equipped with a water inlet ball valve, and the water outlet is equipped with a water outlet ball valve. The temperature control component includes a cooling element and a heating element, which are located at the bottom of the inner tank. The electric mechanism is a ball screw pair driven by a stepper motor. The ball screw pair includes a base, on which a roller is mounted via bearings and bearing seats. A ball screw, one end of which is connected to the output shaft of a stepper motor via a coupling, has a ball nut screwed onto it. A movable tweezers mounting base is fixedly connected to the ball nut. A slider-rail sliding pair connects the movable tweezers mounting base to the base. The slider-rail sliding pair includes a slide rail fixedly connected to the base, a slider mounted on the slide rail, and the slider fixedly connected to the movable tweezers mounting base. The movable tweezers are fixedly connected to the movable tweezers mounting base, and the fixed tweezers mounting base is fixedly connected to the fixed tweezers mounting base. The fixed tweezers mounting base is fixedly connected to a bearing seat. The gripping openings of both the fixed tweezers and the movable tweezers extend downwards into the interior of the water tank.

2. A method for preparing the apparatus for preparing liquid metal microfilaments as described in claim 1, characterized in that, Follow these steps: S1. Pure gallium with a melting point of 29.8℃ is injected into a silicone tube with an inner diameter of D1 and a length of L1 and frozen solidified. The silicone tube is cut open with a scalpel blade to obtain a liquid metal bare wire with a diameter of D1 and a length of L1. S2. For a liquid metal bare wire with a diameter of D1, a polyurethane shell is coated by dipping it in a PU-DMF solution of concentration C at a speed of V1. S3. Clamp both ends of the coated liquid metal wire with a diameter of D1 onto the fixed tweezers and the movable tweezers, respectively. S4. Pour T1 warm water into the water tank until it covers the liquid metal wire with diameter D1; S5. After the liquid metal wire with diameter D1 melts, the electric mechanism is activated, and the movable tweezers mounting base begins to move at a speed of V2, according to the formula... The volume of the microfilament remains unchanged before and after stretching, from By stretching it to N times its original length, a liquid metal microwire with a diameter of D2 can be obtained; S6. Adjust the water temperature using the temperature control component to solidify the drawn liquid metal microwires; S7. After the thinned liquid metal microwire solidifies, remove the microwire and dissolve the polyurethane shell on the surface with tetrahydrofuran to obtain a thinned liquid metal bare wire with a diameter D2.

Images