Three-dimensional compressible liquid metal foam as well as preparation method and regulation and control method thereof
Compressible three-dimensional liquid metal foam is prepared by FDM printing and ultrasonic crushing, which solves the problems of poor shape stability and high surface tension of liquid metals, and achieves efficient preparation of foam and stable Joule thermal performance. It is suitable for flexible electronics and other fields.
Patent Information
- Application Number
- CN202510008122.3
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-01-03
- Publication Date
- 2025-06-13
AI Technical Summary
Due to poor shape stability and high surface tension, liquid metals are difficult to maintain a fixed shape, which affects the performance of electronic devices. The existing preparation methods are complex and not suitable for complex structures.
Three-dimensional anti-template was prepared by FDM printing, and liquid metal ink was prepared by ultrasonic crushing. It was pressed into the anti-template in vacuum. After removing the template, dichloromethane was used to dissolve the anti-template, and finally a compressible three-dimensional liquid metal foam was packaged with flexible material.
It achieves efficient preparation of liquid metal foam and stable Joule thermal performance, overcomes the problems of low viscosity and high surface tension of liquid metals, and is suitable for flexible electronics and intelligent systems and other fields.
Smart Images
Figure CN120138415A_ABST
Abstract
Description
Technical Field
[0001] The present invention belongs to the technical field of electronic devices, and particularly relates to a three-dimensional compressible liquid metal foam, a preparation method thereof, and a regulation method thereof. Background Art
[0002] Liquid metal (LM), such as gallium-indium alloy (EGaIn), has become a hot material in the fields of flexible electronics, energy catalysis, and biomedicine due to its unique fluidity, high electrical conductivity, high thermal conductivity, and excellent stretchability. Especially, its characteristics of both high thermal conductivity and high electrical conductivity make it an ideal choice for electrode materials in flexible electronics and printed electronic devices. However, due to its poor shape stability and low viscosity characteristics, liquid metal is difficult to maintain a fixed shape during the manufacturing process, easily deforms, and thus affects the performance of electronic devices. In addition, an oxide film is easily formed on its surface, which not only weakens the electrical conductivity but also reduces the heat conduction performance. At the same time, the high surface tension also increases the difficulty of coating operations, making precise control and positioning particularly difficult. To address these problems, many studies have been dedicated to improving the processing performance and practicality of liquid metal through innovative processes. For example, Dehai Yu et al. (Zhonghao Wang, Guidong Chi, Qiubo Zhang, Junxian Fu, Nature Communications | (2024) 15:1179) prepared liquid metal foam using fused deposition modeling (FDM) 3D printing technology. After printing the anti-template and pouring liquid metal, the template was removed to obtain a three-dimensional foam structure. However, the encapsulation process of this method is complex, and there is a risk of liquid metal leakage. Salahuddin Ahmed et al. (Marzia Momin, Jiashu Ren, Hyunjin Lee, and Tao Zhou, Adv. Mater. 2024, 2400082) proposed a soft material that self-assembles during the printing process and successfully prepared an asymmetric self-insulating stretchable conductor, fundamentally solving the problem of liquid metal leakage. However, this method has high requirements for the fluid characteristics of the ink, and the preparation process is complicated, and it is not suitable for complex liquid metal foam structures.
[0003] Although the above studies have alleviated the problems of liquid metal processing to a certain extent, their complex preparation processes and application limitations have not been completely overcome. Therefore, there is an urgent need to develop a simple and efficient method to overcome the problems of low viscosity and high surface tension of liquid metal, achieve the efficient preparation of compressible three-dimensional liquid metal foam, and ensure its stable Joule heat performance, so as to provide a more reliable solution for applications in fields such as flexible electronics and intelligent systems. Summary of the Invention
[0004] The object of the present invention is to provide a three-dimensional compressible liquid metal foam, its preparation method and regulation method, which not only overcome the problems of low viscosity and high surface tension of liquid metal, realize the efficient preparation of compressible three-dimensional liquid metal foam, but also ensure the stable Joule heat performance.
[0005] The present invention provides a preparation method of a three-dimensional compressible liquid metal foam, and the preparation method specifically comprises the following steps: S1. Prepare a three-dimensional negative template by means of FDM printing method; S2. Prepare a liquid metal ink by means of ultrasonic crushing method; S3. Press the liquid metal ink prepared in step S2 into the three-dimensional negative template prepared in step S1 under vacuum, and obtain a sample after standing at room temperature; S4. Immerse the sample prepared in step S3 in a dichloromethane solution, take out the liquid metal foam after the three-dimensional negative template is completely dissolved, and obtain a three-dimensional liquid metal foam after drying at room temperature; S5. Package the three-dimensional liquid metal foam obtained in step S4 with a flexible material to obtain a three-dimensional compressible liquid metal foam.
[0006] Compared with the prior art, the specific preparation principle of the present invention is as follows: First, use FDM technology to print polylactic acid (PLA) wire and construct a three-dimensional negative template. Subsequently, in order to reduce the surface tension of the liquid metal, use an ultrasonic cell crusher to process it, and prepare a liquid metal ink through chitosan (CS) modification. Press the liquid metal ink into the three-dimensional negative template under vacuum and stand to ensure its complete solidification. Then, immerse the solidified sample in dichloromethane (DCM) to completely dissolve the PLA negative template, leaving a three-dimensional liquid metal foam. In order to improve the structural strength, use a flexible packaging material to package the three-dimensional liquid metal foam, so that it has compressibility while having conductivity.
[0007] In some other embodiments, in step S1, the specific parameters of the FDM printing method are as follows: the printing wire is polylactic acid, the printer is Raise 3D E2CF, and the size of the three-dimensional negative template is 15×8×5 mm.
[0008] Compared with the prior art, the present invention further defines the parameter settings of FDM printing. Among them, the Raise 3D E2CF printer supports a high printing resolution, which can ensure the accurate reproduction of complex structures and tiny features. The PLA material is soluble in solvents such as dichloromethane, which makes it simple and fast to remove the three-dimensional negative template in the subsequent steps without damaging the liquid metal.
[0009] In some other embodiments, the specific steps of step S2 are as follows: First, configure a chitosan solution, then weigh the liquid metal, mix it with the chitosan solution, transfer it into an ultrasonic cell disruptor, and perform ultrasonic treatment. Set the ultrasonic power to 60% and the ultrasonic time to 30 min to obtain liquid metal ink.
[0010] Compared with the prior art, in the present invention, by mixing a chitosan solution with liquid metal, mainly because liquid metals such as gallium-based alloys usually have a relatively high surface tension, which may limit their fluidity and filling ability in microstructures. Chitosan, as a natural polysaccharide, can reduce the high surface energy of liquid metal, thereby further helping to stabilize these dispersed liquid metal particles and prevent them from re-aggregating. In addition, ultrasonic treatment can effectively break the surface tension of liquid metal, making it easier to form fine dispersed particles or droplets.
[0011] In some other embodiments, the steps for configuring the chitosan solution are as follows: Mix chitosan powder with deionized water, then add acetic acid dropwise, and place it on a stirring table and stir at a speed of 200 rpm for 30 min.
[0012] Compared with the prior art, the reason for preparing the chitosan solution by the above steps in the present invention is mainly that: chitosan is a polysaccharide and is difficult to dissolve in water under neutral or alkaline conditions. By adding an appropriate amount of acetic acid (usually adjusting the pH value to about 4.5 - 5.5), the solubility of chitosan in water can be effectively increased.
[0013] In some other embodiments, the specific operation of step S3 is as follows: Place the three-dimensional anti-template prepared in step S1 at the bottom of a container, pour the liquid metal ink prepared in step S2 into the container to submerge the three-dimensional anti-model, then place the container in a vacuum drying oven for 10 min and take it out, and let the model stand at room temperature for 12 h to obtain a sample.
[0014] Compared with the prior art, the reason for adopting the above steps in the present invention is that: under vacuum conditions, air is pumped out, which helps to eliminate the bubbles between the liquid metal ink and the three-dimensional anti-template, ensuring that the liquid metal can completely fill all the voids of the template, thereby obtaining a more uniform and defect-free sample. At the same time, under the action of negative pressure, the liquid metal ink contacts the surface of the three-dimensional anti-template more closely, which helps to improve the bonding force between the two, thereby increasing the mechanical strength of the finished product.
[0015] In some other embodiments, the specific operation of step S4 is as follows: Place the sample prepared in step S3 in a reagent bottle, pour dichloromethane solution to submerge the sample. After 3 h, the three-dimensional anti-template is completely dissolved, and then the liquid metal foam is taken out and dried at room temperature for 10 min to obtain a three-dimensional liquid metal foam.
[0016] Compared with the prior art, the present invention further utilizes dichloromethane to dissolve the three-dimensional anti-template. This is mainly because dichloromethane has good solubility in PLA, ensuring that the three-dimensional anti-template can be completely dissolved without leaving any residues, thus guaranteeing the purity of the final liquid metal foam structure. At the same time, during the dissolution process, dichloromethane has no obvious chemical effect on the liquid metal and chitosan, so it will not damage the structure of the liquid metal foam, which helps to maintain the integrity of the shape and internal structure of the sample. Compared with high-temperature drying, room-temperature drying can avoid the oxidation of the liquid metal or other changes in physical properties caused by excessive temperature, and enable the three-dimensional LM foam to recover its strength after drying.
[0017] In some other embodiments, in the step S5, the flexible material is flexible polybutylene adipate terephthalate.
[0018] Compared with the prior art, the present invention uses the above flexible material for encapsulation. This is mainly because PBAT has high elasticity and tensile strength, which enables the encapsulated liquid metal foam to withstand repeated compression and stretching without being easily damaged. At the same time, PBAT is a highly flexible material that can easily wrap and adapt to various complex-shaped liquid metal foam structures, ensuring a tight fit, that is, it can improve its strength while maintaining flexibility.
[0019] The second object of the present invention is to provide a three-dimensional compressible liquid metal foam prepared by the above preparation method.
[0020] The third object of the present invention is to provide a temperature control method for a three-dimensional compressible liquid metal foam. The temperature control method specifically includes the following steps: Connect the three-dimensional compressible liquid metal foam to an electrochemical workstation and input a voltage to achieve temperature control by regulating the voltage.
[0021] The present invention also provides the above temperature control method for the three-dimensional compressible liquid metal foam. This is mainly because the test results show that the three-dimensional liquid metal foam has good Joule heat performance, and its temperature changes regularly with the applied voltage. Precise temperature control can be achieved by regulating the voltage, demonstrating broad application potential in the fields of flexible electronics and sensing devices. Description of the Drawings
[0022] Figure 1 It is a schematic diagram of the preparation process of the three-dimensional compressible liquid metal foam; Figure 2 It is a physical picture of the three-dimensional compressible liquid metal foam prepared in Examples 1-3; Figure 3 It is a current change diagram of the three-dimensional compressible liquid metal foam prepared in Example 1 when voltage is applied; Figure 4 Temperature change diagram of the three-dimensional compressible liquid metal foam prepared in Example 1 after connecting voltage; Figure 5 Joule heat performance test diagram of the three-dimensional compressible liquid metal foam prepared in Example 1; Figure 6 Compressible physical diagram of the three-dimensional compressible liquid metal foam prepared in Example 1. Detailed implementation manners
[0023] To make the above objects, features and advantages of the present invention more obvious and understandable, the specific embodiments of the present invention will be described in detail below. It should be noted that the following embodiments are only used to illustrate the implementation methods and typical parameters of the present invention, rather than to limit the parameter range described in the present invention. Reasonable changes derived therefrom are still within the protection scope of the claims of the present invention.
[0024] It should be noted that the endpoints and any values within the ranges disclosed in this article are not limited to the exact ranges or values. These ranges or values should be understood to include values close to these ranges or values. For numerical ranges, between the endpoint values of each range, between the endpoint values of each range and individual point values, and between individual point values, they can be combined with each other to obtain one or more new numerical ranges, and these numerical ranges should be regarded as specifically disclosed in this article.
[0025] Unless otherwise defined, all terms, symbols and other scientific terms used in this article are intended to have the same meaning as commonly understood by those skilled in the art to which the present invention belongs. In some cases, for the purpose of clarification or convenient reference, terms with conventional understood meanings are defined in this article. Such definitions in this article should not be understood as indicating a significant difference from the conventional understanding in the art. The technical methods described or cited in this article are generally well understood by those skilled in the art and are adopted by conventional methods. Unless otherwise stated, the use of commercially available kits, reagents and instruments is carried out according to the protocols and parameters given by the manufacturers.
[0026] The technical effects of the present invention will be described below in conjunction with specific embodiments.
[0027] Example 1 As Figure 1 shown, this embodiment provides a three-dimensional compressible liquid metal foam, which is prepared by the following preparation method: S1. A three-dimensional negative template is prepared by the FDM printing method. The specific parameters of the FDM printing method are as follows: the printing wire is polylactic acid, the printer is Raise 3D E2CF, and the size of the three-dimensional negative template is 15×8×5 mm.
[0028] S2. Prepare the chitosan solution: Completely mix 1.2 mmol of chitosan powder with 15 mL of deionized water, then drop in 50 μL of acetic acid. Place it on a magnetic stirrer and stir at 200 rpm for 30 min until well - mixed. Then weigh 1.5 g of liquid metal and mix it with the obtained chitosan solution. Use an ultrasonic power of 60% for 30 min (model: JY92 - IIN, manufacturer: Scientz) to obtain liquid metal ink; S3. Place the three - dimensional negative template prepared in step S1 at the bottom of a 50 - mL beaker. Take 30 mL of the liquid metal ink prepared in step S2 and pour it into the beaker so that the liquid metal ink submerges the model. Place the beaker in a vacuum drying oven and take it out after 10 min to ensure that the liquid metal ink completely penetrates into the model. Let it stand at room temperature for 12 h to obtain a sample; S4. Put the dried and solidified sample into a 250 - mL glass reagent bottle and pour in 100 mL of dichloromethane. Take out the liquid metal foam after 3 h to completely dissolve the polylactic acid, and then dry it at room temperature for 10 min to obtain three - dimensional liquid metal foam; S5. Encapsulate the three - dimensional liquid metal foam obtained in step S4 with poly(butylene adipate - co - terephthalate) to obtain three - dimensional compressible liquid metal foam.
[0029] Example 2 The difference from Example 1 is only that the size of the three - dimensional negative template used in this example is different, and the others are the same as in Example 1, so they will not be elaborated here.
[0030] Example 3 The difference from Example 1 is only that the style of the three - dimensional negative template used in this example is different, and the others are the same as in Example 1, so they will not be elaborated here.
[0031] Observe the three - dimensional compressible liquid metal foams obtained in Examples 1 - 3, Figure 2 are the physical pictures of the three - dimensional compressible liquid metal foams prepared in Examples 1 - 3. From left to right are the three - dimensional compressible liquid metal foam obtained in Example 1, the three - dimensional compressible liquid metal foam obtained in Example 2, and the three - dimensional compressible liquid metal foam obtained in Example 3; From Figure 2 It can be seen that through experimental verification, the feasibility of printing three - dimensional compressible liquid metal foam by FDM printing technology is proved, and different structural precisions can be printed.
[0032] Connect the three - dimensional compressible liquid metal foam obtained in Example 1 to a voltage, adjust the input voltage, and observe its current situation. The results are as Figure 3 shown. From Figure 3It can be seen that the current changes regularly with the change of voltage, indicating that the electrical properties of the material have good stability.
[0033] Connect the three-dimensional compressible liquid metal foam obtained in Example 1 to a voltage. By adjusting the magnitude of the input voltage, the temperature change of the three-dimensional compressible liquid metal foam is photographed by an infrared thermal imager. The results are as Figure 4 shown. From Figure 4 it can be seen that after the three-dimensional compressible liquid metal foam is connected to different voltages, it shows a stable temperature response, indicating its sensitivity and consistency to voltage changes.
[0034] The joule heat performance of the three-dimensional compressible liquid metal foam obtained in Example 1 is tested. The results are as Figure 5 shown. Figure 5 The left figure shows the symmetry of the temperature change of the three-dimensional compressible liquid metal foam under voltage increase and decrease. Figure 5 The right figure further shows that under different starting voltages, its temperature change law remains consistent, both verifying the stable electrical properties of the three-dimensional compressible liquid metal foam.
[0035] The compression and rebound performance of the three-dimensional compressible liquid metal foam obtained in Example 1 is tested. The results are as Figure 6 shown. From Figure 6 it can be seen that the three-dimensional compressible liquid metal foam has compressibility and can recover after being compressed.
[0036] Although the present disclosure is disclosed as above, the protection scope of the present disclosure is not limited thereto. Those skilled in the art can make various changes and modifications without departing from the spirit and scope of the present disclosure, and these changes and modifications will all fall within the protection scope of the present invention.
Claims
1. A method for preparing a three-dimensional compressible liquid metal foam, characterized in that: The preparation method specifically comprises the following steps: S1, preparing a three-dimensional reverse template by FDM printing method; S2, preparing liquid metal ink by ultrasonic grinding method; S3, pressing the liquid metal ink obtained in step S2 into the three-dimensional reverse template obtained in step S1 by vacuum, and obtaining a sample after standing at room temperature; S4, immersing the sample obtained in step S3 in a dichloromethane solution, taking out the liquid metal foam after the three-dimensional reverse template is completely dissolved, and drying it at room temperature to obtain a three-dimensional liquid metal foam; S5. Encapsulate the three-dimensional liquid metal foam obtained in step S4 with a flexible material to obtain a three-dimensional compressible liquid metal foam.
2. The preparation method according to claim 1, characterized in that In step S1, specific parameters of the FDM printing method are as follows: the printing filament is polylactic acid, the printer is Raise 3D E2CF, and the size of the three-dimensional reverse template is 15×8×5 mm.
3. The preparation method according to claim 1, characterized in that: The specific steps of step S2 are: first preparing a chitosan solution, then weighing liquid metal, mixing it with the chitosan solution and transferring it into an ultrasonic cell crusher for ultrasonic treatment, setting the ultrasonic power to 60% and the ultrasonic time to 30 minutes to obtain liquid metal ink.
4. The preparation method according to claim 3, characterized in that: The preparation steps of chitosan solution are as follows: chitosan powder is mixed with deionized water, acetic acid is added dropwise, and the mixture is placed on a stirring table and stirred at a speed of 200 rpm for 30 minutes.
5. The preparation method according to claim 1, characterized in that: The specific operation of step S3 is as follows: placing the three-dimensional reverse template prepared in step S1 at the bottom of a container, pouring the liquid metal ink prepared in step S2 into the container so that the liquid metal ink submerges the three-dimensional reverse model, and then placing the container in a vacuum drying oven for 10 minutes and then taking it out, and leaving the model to stand at room temperature for 12 hours to obtain a sample.
6. The preparation method according to claim 1, characterized in that: The specific operation of step S4 is as follows: put the sample obtained in step S3 into a reagent bottle, and pour dichloromethane solution into it to immerse the sample. After 3 hours, the three-dimensional reverse template is completely dissolved, so that the liquid metal foam is taken out, and the three-dimensional liquid metal foam is obtained after drying at room temperature for 10 minutes.
7. The preparation method according to claim 1, characterized in that: In the step S5, the flexible material is polybutylene adipate-terephthalate.
8. A three-dimensional compressible liquid metal foam, characterized in that: The method is prepared by any one of claims 1 to 7.
9. A temperature control method for a three-dimensional compressible liquid metal foam as claimed in claim 8, characterized in that: The temperature control method specifically comprises the following steps: After connecting the three-dimensional compressible liquid metal foam to the electrochemical workstation, the voltage is input and the temperature is controlled by adjusting the voltage.