A method for preparing liquid metal magnetic fluid and magnetic liquid metal micro / nano particles

Abstract

This invention relates to the field of alloy materials technology, specifically to a method for preparing liquid metal magnetic fluid and magnetic liquid metal micro / nano particles. The method for preparing liquid metal magnetic fluid and magnetic liquid metal micro / nano particles provided by this invention is simple to operate, easy to implement, and has a short preparation time and good process stability. The entire process of preparing liquid metal magnetic fluid using the vortex method takes only about 20 minutes. The obtained liquid metal magnetic fluid can then be further used to prepare magnetic liquid metal micro / nano particles using the vortex method, with the preparation time for magnetic liquid metal micro / nano particles not exceeding 20 minutes, greatly improving production efficiency.

Description

Technical Field

[0001] This invention relates to the field of alloy materials technology, specifically to a method for preparing liquid metal magnetic fluid and magnetic liquid metal micro / nano particles. Background Technology

[0002] Liquid metal magnetic fluids, unlike traditional magnetic fluids that use water, oil, or organic solvents as carriers, possess excellent conductivity, high density, high boiling point, and chemical stability, greatly expanding the functionality of magnetic fluids. Gallium-based magnetic liquid metal micro / nano particles exhibit good biocompatibility, magnetic responsiveness, responsiveness to stimuli such as acousto-optical-thermal-electrical stimuli, fluidity, and modifiability. Liquid metal magnetic fluids and magnetic liquid metal micro / nano particles demonstrate diverse functionalities and can be widely used in fields such as biomedical engineering, thermal management, printing, patterning, flexible sensors, and soft robotics.

[0003] In existing technologies, liquid metal magnetic fluids are prepared by mechanical stress such as grinding (Elbourne A, Cheeseman S, Atkin P, et al. Antibacterial Liquid Metals: Biofilm Treatment via Magnetic Activation[J]. ACS Nano, 2020, 14(1): 802-17) or by solvents such as hydrochloric acid (Tang J, Zhao X, Li J, et al. Liquid Metal Phagocytosis: Intermetallic Wetting Induced Particle Internalization[J]. Advanced Science, 2017, 4(5): 1700024). Mechanical stimulation methods such as grinding typically place the liquid metal and magnetic particles in an inert environment, removing oxides from both substances through mechanical shear stress, allowing them to come into direct contact, triggering the liquid metal's absorption process, and promoting the formation of the liquid metal magnetic fluid. However, grinding methods are cumbersome in their preparation process and suffer from low manufacturing efficiency and a low magnetic particle filling ratio. Solvent-based preparation methods typically involve immersing liquid metal and magnetic particles in a solution such as hydrochloric acid and stirring, followed by rinsing and vacuum drying to prepare liquid metal magnetic fluid. The solution removes oxides, allowing the magnetic particles and liquid metal to come into contact, triggering an absorption process and the formation of the liquid metal magnetic fluid. This method is cumbersome, and the filling ratio of magnetic particles is also limited. When using acidic solutions such as hydrochloric acid, the hydrochloric acid reacts with the liquid metal and magnetic particles such as iron, resulting in raw material loss; furthermore, the hydrogen gas generated during this process hinders the contact between the magnetic particles and liquid metal, affecting the formation of the liquid metal magnetic fluid. Preparation using alkaline or neutral solutions requires additional steps, such as polarization or using sacrificial metals to electrochemically reduce the liquid metal and magnetic particles, making the process quite cumbersome. The prepared liquid metal magnetic fluid can be dispersed into micro / nano structures using ultrasonication, becoming magnetic liquid metal micro / nano particles. However, as the filling ratio of magnetic particles increases, the liquid metal magnetic fluid exhibits a harder texture, and ultrasonication may be insufficient to disperse it into micro / nano structures. Summary of the Invention

[0004] To address the aforementioned shortcomings in the prior art, the present invention aims to provide a method for preparing liquid metal magnetic fluid and magnetic liquid metal micro / nano particles, thereby solving the following technical problems:

[0005] 1. The problem of low magnetic particle filling ratio in liquid metal magnetofluid;

[0006] 2. The complexity of the fabrication process for liquid metal magnetofluids and magnetic liquid metal micro / nano particles;

[0007] 3. The ultrasonic method is not suitable for dispersing liquid metal magnetic fluids with a high proportion of highly magnetic particles.

[0008] To achieve the above-mentioned objectives, the technical solution adopted by this invention is as follows:

[0009] In a first aspect, a method for preparing a liquid metal magnetic fluid is provided, comprising the following steps: adding magnetic particles into liquid metal and obtaining the liquid metal magnetic fluid by vortex mixing.

[0010] Furthermore, the magnetic particles are reduced iron powder or iron(III) oxide nanoparticles.

[0011] Furthermore, the liquid metal is gallium, or a gallium-indium binary alloy, or a gallium-indium-tin ternary alloy.

[0012] Furthermore, the mass ratio of magnetic particles to liquid metal is (0.1-5):5.

[0013] Furthermore, the vortex mixing time is 5-25 minutes, and the rotation speed is 1000-20000 rpm.

[0014] On the other hand, a method for preparing magnetic liquid metal micro / nano particles is provided, in which liquid metal magnetic fluid is added to a dispersion, and a solution containing magnetic liquid metal micro / nano particles of different sizes is obtained by vortex dispersion, followed by filtration and screening to obtain magnetic liquid metal micro / nano particles of specific sizes.

[0015] Furthermore, the dispersion is a chitosan oligosaccharide solution or pure water.

[0016] Furthermore, the mass ratio of the liquid metal magnetic fluid to the dispersion is (0.1-5):5.

[0017] Furthermore, the vortex dispersion vortex time is 1-5 minutes, and the rotation speed is 8000-10000 rpm.

[0018] The beneficial effects of this invention are as follows:

[0019] 1. The preparation method of liquid metal magnetic fluid and magnetic liquid metal micro / nano particles provided by this invention is simple to operate and easy to implement, with short preparation time and good process stability. The entire process of preparing liquid metal magnetic fluid using the vortex method takes only about 20 minutes. The obtained liquid metal magnetic fluid can then be used to prepare magnetic liquid metal micro / nano particles using the vortex method. The preparation of magnetic liquid metal micro / nano particles takes no more than 20 minutes, greatly improving production efficiency.

[0020] 2. The preparation method of liquid metal magnetic fluid and magnetic liquid metal micro / nano particles provided by the present invention involves few types of raw materials, only liquid metal, magnetic particles and dispersion liquid, which reduces raw material consumption and production costs; at the same time, it reduces the use of harmful chemicals (such as hydrochloric acid) and reduces operational risks.

[0021] 3. The liquid metal magnetic fluid preparation method provided by this invention can be used to prepare liquid metal magnetic fluids with a higher magnetic particle filling ratio; the preparation method of magnetic liquid metal micro / nano particles can screen magnetic liquid metal micro / nano particles of different sizes by adjusting the vortex time and the size of the filter membrane to meet different needs.

[0022] 4. The vortex preparation method provided by this invention solves the problem that the ultrasonic method is difficult to effectively disperse liquid metal magnetic fluid with a high magnetic particle filling ratio (φ≥44.4%). Attached Figure Description

[0023] Figure 1 This is a flowchart of the preparation process of liquid metal magnetofluid in Example 1;

[0024] Figure 2 Macroscopic images of liquid metal magnetofluids with different magnetic particle filling ratios prepared in Example 1;

[0025] Figure 3 The magnetic response image of the liquid metal magnetofluid with a magnetic particle filling ratio of 44.4% prepared for Example 1;

[0026] Figure 4 This is a flowchart illustrating the preparation process of magnetic liquid metal micro / nanoparticles in Example 2.

[0027] Figure 5 The image shows the characterization results of the magnetic liquid metal micro / nanoparticles prepared in Example 2. Detailed Implementation

[0028] The specific embodiments of the present invention are described below to enable those skilled in the art to understand the present invention. However, it should be understood that the present invention is not limited to the scope of the specific embodiments. For those skilled in the art, various changes are obvious as long as they are within the spirit and scope of the present invention as defined and determined by the appended claims. All inventions utilizing the concept of the present invention are protected.

[0029] Example 1

[0030] This embodiment follows the following... Figure 1 The process flow shown is used to prepare a liquid metal magnetic fluid, and the specific steps are as follows:

[0031] (1) Weigh 2g of pure gallium into a 5mL centrifuge tube, and then add 0.4, 0.8, 1.2, 1.6 and 2.0g of reduced iron powder respectively.

[0032] (2) Use a magnet to attract the iron powder to the bottom of the bottle and mix it initially.

[0033] (3) Then, vortex mix the magnetic particles and liquid metal at a speed of 9000 rpm for 15 minutes (VortexGenie2 vortex mixer, single test tube head gasket) to obtain liquid metal magnetic fluid.

[0034] The magnetic particle filling ratio in the liquid metal magnetic fluid can be 0-50%. A lower magnetic particle filling ratio results in no magnetism, while a higher ratio results in no fluidity. The magnetic particle filling ratios of the liquid metal magnetic fluid prepared in Example 1 were 16.7%, 28.6%, 37.5%, 44.4%, and 50%, respectively (magnetic particle filling ratio φ = magnetic particle mass / liquid metal magnetic fluid mass × 100%). Figure 2 Macroscopic images of liquid metal magnetofluids with different magnetic particle filling ratios. Figure 3 Image of the magnetic response of a liquid metal magnetofluid with a magnetic particle filling ratio of 44.4%.

[0035] Example 2

[0036] This embodiment follows the following... Figure 4 The process flow shown is used to prepare magnetic liquid metal micro / nano particles. The specific steps are as follows:

[0037] (1) Prepare a 40 mg / mL chitosan oligosaccharide solution and take 10 mL into a 50 mL centrifuge tube.

[0038] (2) Add 3.6g of liquid metal magnetic fluid (magnetic particle filling ratio of 44.4%) to chitosan oligosaccharide solution.

[0039] (3) Vortex the mixture at 9000 rpm for 3 minutes (VortexGenie2 vortex mixer, single test tube head gasket).

[0040] (4) Use a 100μm cell sieve to filter the vortexed mixture to remove magnetic particles with a diameter greater than 100μm; then use a 40μm cell sieve to filter to remove magnetic particles with a diameter less than 40μm, thus obtaining magnetic liquid metal micro-nano particles with a diameter between 40-100μm.

[0041] The characterization results of the magnetic liquid metal micro / nanoparticles prepared in Example 2 are as follows: Figure 5 Scale bar: 25 μm. Elemental analysis shows that magnetic liquid metal micro / nano particles have been successfully prepared.

[0042] In summary, this invention optimizes the hardness, fluidity, and magnetism of liquid metal magnetic fluids by adjusting the filling ratio of magnetic particles, making them suitable for various applications. The method for preparing magnetic liquid metal micro / nano particles provided by this invention can disperse the obtained liquid metal magnetic fluid into micro / nano structures, supplementing the demand for magnetic liquid metal micro / nano particles.

[0043] 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 the spirit or essential characteristics of the invention. 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, it is intended that all variations falling within the meaning and scope of equivalents of the claims be included within the present invention.

Claims

1. A method for preparing magnetic liquid metal microparticles, characterized by, The method comprises the following steps: The magnetic particles are added into the liquid metal to obtain a liquid metal magnetic fluid by vortex mixing, then the liquid metal magnetic fluid is added into a dispersion liquid to obtain a magnetic liquid metal micro-nano particle solution with different sizes by vortex dispersion, and then the magnetic liquid metal micro-nano particle solution with a particle size of 40-100 microns is obtained by filtering and screening.

2. The method for preparing magnetic liquid metal micro / nano particles according to claim 1, characterized in that, The magnetic particles are reduced iron powder or Fe3O4 nano particles.

3. The method for preparing magnetic liquid metal micro / nano particles according to claim 1, characterized in that, The liquid metal is gallium, a gallium-indium binary alloy or a gallium-indium-tin ternary alloy.

4. The method for preparing magnetic liquid metal micro / nano particles according to claim 1, characterized in that, The mass ratio of the magnetic particles to the liquid metal is (0.1-5):

5.

5. The method of claim 1, wherein the magnetic liquid metal microparticles are prepared by the steps of: providing a liquid metal; providing a magnetic field; and applying a magnetic field to the liquid metal to form the magnetic liquid metal microparticles. The vortex time is 5-25 minutes, and the rotation speed is 1000-20000 rpm.

6. The method of claim 1, wherein the magnetic liquid metal microparticles are prepared by the steps of: providing a liquid metal; providing a magnetic field; and applying a magnetic field to the liquid metal to form the magnetic liquid metal microparticles. The dispersion liquid is a chitosan oligosaccharide solution or pure water.

7. The method of claim 6, wherein the magnetic liquid metal microparticles are prepared by the method comprising: The mass ratio of the liquid metal magnetic fluid to the dispersion liquid is (0.1-5):

5.

8. The method of claim 1, wherein the magnetic liquid metal microparticles are prepared by the method comprising: The vortex time is 1-5 minutes, and the rotation speed is 8000-10000 rpm.

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