Method for ultrasonic-assisted construction of complex structures of magnetic liquid metal
By using ultrasonic-assisted infusion and PDMS mold preparation, the problems of fluidity and uneven forming of magnetic liquid metal in complex three-dimensional structures have been solved, achieving high-precision and uniform magnetic response performance, which is suitable for the manufacture of various complex structures.
Patent Information
- Application Number
- CN202610553816.X
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2026-04-24
- Publication Date
- 2026-08-04
AI Technical Summary
Existing technologies struggle to efficiently and stably construct complex three-dimensional structures of magnetic liquid metals, especially when dealing with complex structures such as closed cavities and multi-branched networks, resulting in problems such as poor fluidity, uneven forming, and inconsistent magnetic properties.
An ultrasonic-assisted infusion method is adopted, which uses ultrasonic vibration field to intervene in the flow state and dynamically control the particle distribution of magnetic liquid metal. Combined with PDMS mold preparation and ultrasonic premixing, efficient infusion and molding of liquid metal in complex structures can be achieved.
It significantly improves the fluidity and forming integrity of liquid metal in three-dimensional complex structures, reduces defects caused by residual bubbles and magnetic particle sedimentation, and achieves high-precision and uniform magnetic response performance.
Smart Images
Figure CN122500139A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of functional materials processing and manufacturing technology, and in particular to a method for constructing complex magnetic liquid metal structures with ultrasonic assistance. Background Technology
[0002] Magnetic Ga-based liquid metals are a class of functional composite materials that exist in a liquid state at room temperature. They possess physicochemical properties such as low melting point, high electrical and thermal conductivity, excellent flowability, and biocompatibility. Especially after incorporating ferromagnetic particles (such as NdFeB and Fe3O4), they acquire the ability to respond to applied magnetic fields, making them widely applicable in cutting-edge fields such as magnetically controlled robotic soft robots, biosensors, and flexible electronic devices. In these applications, it is often necessary to construct magnetic liquid metals into three-dimensional micro / nano structures with complex cross-linking to achieve precise magnetic field response control, high spatial integration, and differentiated design of functional regions. Therefore, how to efficiently, stably, and controllably process magnetic liquid metals into complex shapes and fine-scale structures has become one of the key technological bottlenecks restricting their widespread application.
[0003] Currently, the main molding processes for magnetic liquid metal structures include injection molding, centrifugation, vacuum infusion, magnetic field-assisted infusion, and magnetic inkjet printing. These methods are relatively mature in constructing simple structures or two-dimensional patterns, but their molding results are often unsatisfactory when dealing with highly complex three-dimensional microchannels, closed cavities, or multi-branched network structures. Firstly, in traditional injection molding, the liquid metal relies on pressure difference to drive flow, making it difficult to effectively traverse channels with high aspect ratios or high curvature. This easily leads to defects such as flow stagnation, bubble blockage, or incomplete filling at structural dead corners and narrow connections. Secondly, magnetic particles tend to settle and aggregate during infusion due to gravity, further exacerbating uneven molding or causing magnetic property mismatch. Furthermore, existing methods lack active control over the flow state of the liquid metal, failing to dynamically adjust its infusion behavior at the microscale or adaptively adjust the flow rate based on the local complexity of the structure. This limits their adaptability to complex three-dimensional structures and their molding accuracy.
[0004] Especially when constructing typical complex structures such as closed spiral channels, micro-spherical cavities, bi-branch networks, and multi-stage diversion pipes, traditional methods cannot guarantee uniform and continuous infusion of magnetic liquid metal in all areas, ultimately leading to structural defects, inconsistent interfaces, or even overall failure. Furthermore, to improve fluidity, some methods attempt to increase infusion pressure or reduce the viscosity of the liquid metal, but these measures often trigger secondary problems such as mold rupture, material leakage, or particle destabilization, increasing experimental uncertainty and process complexity. Therefore, there is currently a lack of an efficient magnetic liquid metal molding method suitable for constructing complex three-dimensional structures that balances flow stability and molding accuracy without compromising the intrinsic properties of the material.
[0005] While existing magnetic liquid metal molding technology has found some application in two-dimensional pattern fabrication and simple microstructure construction, several technical bottlenecks remain in constructing complex three-dimensional structures. On one hand, due to density mismatch in liquid metal, sedimentation and aggregation of magnetic particles during flow are difficult to avoid. This is especially true when there are significant flow rate variations, complex paths, or multiple branch nodes during the infusion process, leading to irregular accumulation of magnetic particles in localized areas, resulting in uneven infusion and spatial inconsistencies in magnetic response performance. On the other hand, liquid metal itself has high surface tension and viscosity, easily creating stagnant regions in microstructures, leading to filling defects such as bubbles, short circuits, or cavities, severely limiting the molding accuracy and performance stability of the final device.
[0006] More importantly, traditional methods generally lack the ability to intervene in and dynamically control the flow behavior of liquid metal in the mold in real time. When faced with complex structures such as spirals, closed cavities, or microscale branching networks, the flow of liquid metal in the channels is easily limited by changes in channel cross-section, bending angles, or local friction in the mold, ultimately leading to flow interruption at the front end or adhesion at the boundary. Furthermore, relying solely on pressure-driven or vacuum suction methods is insufficient to achieve efficient propagation and precise coverage of liquid metal in all microcavity regions, resulting in a high molding failure rate and failing to meet the stringent requirements of structural integrity and functional continuity for complex devices. Therefore, there is an urgent need for a novel approach with flow enhancement and spatial perturbation capabilities to improve the molding consistency and efficiency of magnetic liquid metal in the construction of complex structures from a physical mechanism perspective. Summary of the Invention
[0007] This invention provides a method for constructing complex magnetic liquid metal structures with ultrasonic assistance. The aim is to use an ultrasonic vibration field to cast magnetic liquid metal, thereby achieving physical intervention in the flow state of the liquid metal and dynamic control of the spatial distribution of particles. This improves its filling ability and morphological fidelity in three-dimensional complex structures, and solves the problems of poor fluidity, easy generation of bubbles, easy settling of magnetic particles leading to many molding defects and low precision when magnetic liquid metal is used to cast complex three-dimensional structures.
[0008] To achieve the above objectives, the present invention provides a method for constructing complex magnetic liquid metal structures with ultrasound assistance, the method comprising the following steps: S10, Mold preparation: A soluble resin positive mold with a target complex spatial structure is manufactured using digital light processing 3D printing technology; based on the resin positive mold, an elastic PDMS mold with a three-dimensional closed cavity is prepared using PDMS casting technology; S20, Preparation of magnetic liquid metal: Neodymium iron boron magnetic particles are mixed with liquid gallium metal, and then ground, stirred and ultrasonically premixed to prepare a uniform magnetic liquid metal composite material. S30, Ultrasonic-assisted infusion: The PDMS mold is mounted on an ultrasonic coupling platform, and the magnetic liquid metal composite material is injected into the infusion port of the mold. At the same time, an ultrasonic field is applied to the PDMS mold during the infusion process. S40, Post-processing: After the infusion is completed, the PDMS mold is dissolved in a solvent at a temperature below the melting point of the magnetic liquid metal to obtain an independent complex three-dimensional structure of magnetic liquid metal.
[0009] A further technical solution of the present invention is that, in step S30, the frequency of the ultrasonic field is 20kHz and the power is 27W.
[0010] A further technical solution of the present invention is that the mass fraction of the neodymium iron boron magnetic particles is 10%.
[0011] A further technical solution of the present invention is that the solvent in step S40 is a mixed solvent of tetrabutylammonium fluoride and acetone, with a volume ratio of 1:4.
[0012] A further technical solution of the present invention is that, in step S10, the step of preparing an elastic PDMS mold with a three-dimensional closed cavity using PDMS molding technology includes: Liquid PDMS is poured and wrapped around the resin male mold, and after heating and curing, an elastic PDMS-wrapped mold that can sacrifice the resin male mold is formed. A mold in which a sacrificial resin male mold is wrapped with elastic PDMS is placed in an alkaline solution and heated to dissolve the resin male mold, thereby obtaining a PDMS female mold with a complex three-dimensional cavity structure.
[0013] A further technical solution of the present invention is that the alkaline solution is a 5 mol / L NaOH solution, and the heating and dissolution temperature is 150°C.
[0014] A further technical solution of the present invention is that the target complex spatial structure is at least one of a spiral pipe, a spherical network, and an interlaced branch structure.
[0015] The beneficial effects of the method for constructing complex magnetic liquid metal structures with ultrasound assistance according to the present invention are: This invention presents a method for constructing complex magnetic liquid metal structures using ultrasound assistance, overcoming key limitations of traditional injection and vacuum infusion techniques in the molding of complex three-dimensional structures. By introducing an ultrasonic physical perturbation mechanism, it significantly improves the fluidity, channel adaptability, and structural integrity of the liquid metal. In practical applications, this method exhibits excellent structural fidelity and high consistency, especially when dealing with structures such as long-distance channels, micrometer-scale branching networks, and multi-layered closed cavities. It effectively avoids common problems in traditional methods, such as incomplete filling, residual bubbles, and boundary collapse.
[0016] Furthermore, the cavitation effect of ultrasound during the injection process helps to break the oxide film on the surface of the liquid metal and the attached air bubbles on the inner wall of the mold, thereby reducing the molding defect rate; while the acoustic radiation force can dynamically maintain the suspension state of magnetic particles in the liquid, improving the magnetic response consistency and functional uniformity of the final structure. Compared with the prior art, this invention can achieve high-performance three-dimensional molding without special modification of the mold structure or material system, has strong process versatility, and is suitable for the combined manufacturing of various magnetic materials and complex structures.
[0017] The novel magnetic liquid metal manufacturing technology proposed in this invention, characterized by high structural complexity, high molding precision, and strong controllability of the operation process, provides reliable engineering methods and theoretical support for emerging application fields such as magnetically controlled microsystems, flexible sensors, and biomedical micro-platforms, and has good industrialization prospects and promotion potential. Attached Figure Description
[0019] Figure 1 This is a flowchart illustrating a preferred embodiment of the method for constructing complex magnetic liquid metal structures with ultrasound assistance according to the present invention. Figure 2 This is a schematic diagram of a soluble resin positive mold model for printing complex spatial structures. Figure 3 This is a schematic diagram of ultrasonically filled magnetic liquid metal; Figure 4 This is a schematic diagram of the complex three-dimensional structure of the magnetic liquid metal after the PDMS mold has been dissolved. Detailed Implementation
[0020] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments.
[0021] This invention proposes a method for constructing complex magnetic liquid metal structures with ultrasonic assistance. The technical solution adopted in this invention mainly utilizes the effect of acoustic flow to improve the fluid's adaptability to complex channels when ultrasonic waves are applied to the liquid metal system. The cavitation effect is used to destroy attached air bubbles and clear dead corners. At the same time, the acoustic radiation force is used to suppress particle sedimentation and improve particle suspension stability, so that the entire molding process can achieve rapid and efficient injection while ensuring accuracy.
[0022] This method, through precise control of parameters such as ultrasonic frequency, power, and duration, constructs a liquid metal infusion environment adapted to different channel characteristics. Without altering the material composition or mold structure, it enhances the morphological control of liquid metal in complex spaces. This "ultrasound-fluid-structure" coupling strategy not only solves the traditional molding challenges of magnetic liquid metal in three-dimensional complex structures but also provides technical support for constructing high-throughput, high-resolution magnetic response devices and flexible magnetic circuit networks, demonstrating significant theoretical value and application prospects.
[0023] Specifically, such as Figure 1 As shown, a preferred embodiment of the method for constructing complex magnetic liquid metal structures with ultrasound assistance according to the present invention includes the following steps.
[0024] S10, Mold Preparation: A soluble resin positive mold with a target complex spatial structure is manufactured using digital light processing 3D printing technology; based on the resin positive mold, an elastic PDMS mold with a three-dimensional closed cavity is prepared using PDMS casting technology. The target complex spatial structure includes at least one of the following: a spiral pipe, a spherical network, and an interlaced branch structure.
[0025] The specific steps of preparing an elastic PDMS mold with a three-dimensional closed cavity using PDMS molding technology based on the resin positive mold include: Liquid PDMS is poured and wrapped around the resin male mold, and after heating and curing, an elastic PDMS-wrapped mold that can sacrifice the resin male mold is formed. A mold in which a sacrificial resin male mold is encapsulated in elastic PDMS is placed in an alkaline solution and heated to dissolve the resin male mold, thereby obtaining a PDMS female mold with a complex three-dimensional cavity structure. The alkaline solution is a 5 mol / L NaOH solution, and the heating and dissolution temperature is 150°C.
[0026] S20, Preparation of magnetic liquid metal: Neodymium iron boron magnetic particles are mixed with liquid gallium metal, and then ground, stirred and ultrasonically premixed to prepare a uniform magnetic liquid metal composite material.
[0027] The mass fraction of the neodymium iron boron magnetic particles is 10%.
[0028] S30, Ultrasonic-assisted infusion: The PDMS mold is mounted on an ultrasonic coupling platform, and the magnetic liquid metal composite material is injected into the infusion port of the mold. At the same time, an ultrasonic field is applied to the PDMS mold during the infusion process.
[0029] The ultrasonic field has a frequency of 20kHz and a power of 27W.
[0030] S40, Post-processing: After the infusion is completed, the PDMS mold is dissolved in a solvent at a temperature below the melting point of the magnetic liquid metal to obtain an independent complex three-dimensional structure of magnetic liquid metal.
[0031] The solvent is a mixture of tetrabutylammonium fluoride and acetone in a volume ratio of 1:4.
[0032] The following combination Figures 1 to 3 The method for constructing complex magnetic liquid metal structures with ultrasound assistance according to the present invention will be further described in detail.
[0033] The core of this invention's method for ultrasonically assisted construction of complex magnetic liquid metal structures lies in the process of injecting magnetic liquid metal into a pre-fabricated three-dimensional polydimethylsiloxane (PDMS) microstructure mold, using an ultrasonic field to regulate its flow behavior and forming path, thereby achieving high-fidelity replication of complex geometric morphologies. This method mainly includes the following steps: First, using digital light processing (DLP) 3D printing technology, a soluble resin positive mold with a complex spatial structure is printed, such as... Figure 2 As shown, an elastic mold with a three-dimensional closed cavity is then prepared using PDMS casting technology. The steps involve pouring liquid PDMS material to encapsulate a resin positive mold, followed by placing it in an oven at approximately 100°C. Due to the heat-curing properties of PDMS, an elastic PDMS-encapsulated sacrificial resin positive mold is obtained after heating. Finally, the mold is placed in 200 ml of a 5 mol / L NaOH solution at 150°C to dissolve the sacrificial resin positive mold, ultimately yielding a PDMS negative mold. The mold structure can include typical complex morphologies such as spiral channels, spherical networks, and intersecting branches, exhibiting micron-level resolution and high morphology fidelity.
[0034] Magnetic liquid metal is prepared by mixing neodymium iron boron (NdFeB) magnetic particles with liquid Ga, wherein the NdFeB magnetic particles account for 10% by mass. Grinding, stirring, and preliminary ultrasonic premixing are employed to improve its uniformity and stability. During infusion, the PDMS mold is mounted on a titanium alloy ultrasonic coupling platform, such as... Figure 3 As shown, magnetic liquid metal was injected into the ultrasonic tank of the mold design beforehand. During the entire injection process, ultrasonic vibrations of 20 kHz and 27 W were applied. The ultrasonic field at the coupling surface generated acoustic flow and local pressure disturbance inside the mold, breaking the static boundary layer and adhesive wall flow of the liquid metal in the complex channels, thus improving its propagation speed and morphology control in the three-dimensional structure. Finally, by dissolving the PDMS mold in a mixed solvent of tetrabutylammonium fluoride and acetone (volume ratio 1:4) at a temperature lower than the melting point of the magnetic liquid metal (29.5 ℃), a complete magnetic liquid metal solid structure with complex geometry was obtained, such as... Figure 4 As shown.
[0035] The beneficial effects of the method for constructing complex magnetic liquid metal structures with ultrasound assistance according to the present invention are: This invention presents a method for constructing complex magnetic liquid metal structures using ultrasound assistance, overcoming key limitations of traditional injection and vacuum infusion techniques in the molding of complex three-dimensional structures. By introducing an ultrasonic physical perturbation mechanism, it significantly improves the fluidity, channel adaptability, and structural integrity of the liquid metal. In practical applications, this method exhibits excellent structural fidelity and high consistency, especially when dealing with structures such as long-distance channels, micrometer-scale branching networks, and multi-layered closed cavities. It effectively avoids common problems in traditional methods, such as incomplete filling, residual bubbles, and boundary collapse.
[0036] Furthermore, the cavitation effect of ultrasound during the injection process helps to break the oxide film on the surface of the liquid metal and the attached air bubbles on the inner wall of the mold, thereby reducing the molding defect rate; while the acoustic radiation force can dynamically maintain the suspension state of magnetic particles in the liquid, improving the magnetic response consistency and functional uniformity of the final structure. Compared with the prior art, this invention can achieve high-performance three-dimensional molding without special modification of the mold structure or material system, has strong process versatility, and is suitable for the combined manufacturing of various magnetic materials and complex structures.
[0037] The novel magnetic liquid metal manufacturing technology proposed in this invention, characterized by high structural complexity, high molding precision, and strong controllability of the operation process, provides reliable engineering methods and theoretical support for emerging application fields such as magnetically controlled microsystems, flexible sensors, and biomedical micro-platforms, and has good industrialization prospects and promotion potential.
[0038] The above description, in conjunction with specific preferred embodiments, provides a further detailed explanation of the present invention. It should not be construed that the specific implementation of the present invention is limited to these descriptions. For those skilled in the art, various simple deductions or substitutions can be made without departing from the concept of the present invention, and all such modifications and substitutions should be considered within the scope of protection of the present invention.
Claims
1. A method for constructing complex magnetic liquid metal structures with ultrasound assistance, characterized in that, The method includes the following steps: S10, Mold preparation: A soluble resin positive mold with a target complex spatial structure is manufactured using digital light processing 3D printing technology; based on the resin positive mold, an elastic PDMS mold with a three-dimensional closed cavity is prepared using PDMS casting technology; S20, Preparation of magnetic liquid metal: Neodymium iron boron magnetic particles are mixed with liquid gallium metal, and then ground, stirred and ultrasonically premixed to prepare a uniform magnetic liquid metal composite material. S30, Ultrasonic-assisted infusion: The PDMS mold is mounted on an ultrasonic coupling platform, and the magnetic liquid metal composite material is injected into the infusion port of the mold. At the same time, an ultrasonic field is applied to the PDMS mold during the infusion process. S40, Post-processing: After the infusion is completed, the PDMS mold is dissolved in a solvent at a temperature below the melting point of the magnetic liquid metal to obtain an independent complex three-dimensional structure of magnetic liquid metal.
2. The method for constructing complex magnetic liquid metal structures with ultrasound assistance according to claim 1, characterized in that, In step S30, the frequency of the ultrasonic field is 20kHz and the power is 27W.
3. The method for constructing complex magnetic liquid metal structures with ultrasound assistance according to claim 1, characterized in that, The mass fraction of the neodymium iron boron magnetic particles is 10%.
4. The method for constructing complex magnetic liquid metal structures with ultrasound assistance according to claim 1, characterized in that, The solvent in step S40 is a mixture of tetrabutylammonium fluoride and acetone in a volume ratio of 1:
4.
5. The method for constructing complex magnetic liquid metal structures with ultrasound assistance according to claim 1, characterized in that, In step S10, the step of preparing an elastic PDMS mold with a three-dimensional closed cavity using PDMS molding technology includes: Liquid PDMS is poured and wrapped around the resin male mold, and after heating and curing, an elastic PDMS-wrapped mold that can sacrifice the resin male mold is formed. A mold in which a sacrificial resin male mold is wrapped with elastic PDMS is placed in an alkaline solution and heated to dissolve the resin male mold, thereby obtaining a PDMS female mold with a complex three-dimensional cavity structure.
6. The method for constructing complex magnetic liquid metal structures with ultrasound assistance according to claim 5, characterized in that, The alkaline solution is a 5 mol / L NaOH solution, and the heating and dissolution temperature is 150℃.
7. The method for constructing complex magnetic liquid metal structures with ultrasound assistance according to claim 1, characterized in that, The target complex spatial structure is at least one of the following: a spiral pipe, a spherical network, or an interlaced branch structure.