Liquid metal transient circuit and preparation method and application thereof

Abstract

The application discloses a liquid metal transient circuit and a preparation method and application thereof, and belongs to the technical field of electronic circuits. The liquid metal transient circuit is constructed by printing or brushing a liquid metal slurry, wherein the liquid metal slurry is a composite material with non-Newtonian fluid properties formed by compounding liquid metal and a second phase substance; the whole or part of the transient circuit can be quickly disintegrated under the stimulation of acid, alkali, salt, water or alcohol solution. The liquid metal is selected from one to five alloys of gallium, indium, tin, zinc and bismuth, and the second phase substance is selected from aluminum, magnesium and alloy particles or degradable polymer particles. The preparation method comprises the following steps: mixing to prepare the slurry, designing the circuit structure, and printing or brushing to construct the circuit. The application has the advantages of simple construction method, low cost, circuit disintegration independent of substrate decomposition, fast response speed, and suitability for water level warning, information anti-counterfeiting and medical electronics scenes.

Description

Technical Field

[0001] This invention belongs to the field of electronic circuit technology, and particularly relates to a liquid metal transient circuit, its preparation method and application. Background Technology

[0002] With the advent of the electrification era, electronic devices with various functions have become ubiquitous in daily life. On the one hand, due to the lack of simple and efficient recycling strategies, a large number of manufactured and obsolete electronic devices are discarded or landfilled, leading to serious resource waste and environmental problems. On the other hand, with the improvement of living standards and the advancement of application concepts, more and more fields hope that electronic devices can operate stably and with high performance within a predetermined time frame, after which they can degrade on their own, avoiding problems such as recycling, secondary processing, or information leakage. Therefore, unlike traditional physically immutable electronic devices, there is an urgent need to develop new types of electronic devices with transient properties.

[0003] As a crucial component of electronic devices, circuits play a vital role in connecting various parts and conducting electrical energy. Traditional copper-clad laminate-based printed circuits not only involve complex fabrication processes but also often introduce toxic metals such as mercury, lead, and cadmium, as well as recalcitrant polymer substrates, making it difficult to meet the requirements of transient circuits. In recent years, some research has gradually emerged on the development of transient circuits. Due to the involvement of solid-phase materials and thin films, these circuits mostly require complex fabrication processes, such as anisotropic chemical etching, transfer printing, physical vapor deposition, and multi-step additive manufacturing.

[0004] Liquid metals, as an emerging class of functional materials, possess both metallic and fluid properties, demonstrating immense potential and application prospects in the field of flexible printed circuits. Thanks to their liquid properties, liquid metals have been found to be able to construct complex characters and patterns using various techniques (such as selective wetting, direct writing, and vacuum filtration). Therefore, constructing transient circuits based on liquid metals will greatly simplify the fabrication process. While there are reports on liquid metal transient circuits, most rely on the degradation of the substrate material to achieve the transient nature of the circuit, rather than the decomposition of the conductor itself. The degradation of polymer materials involves the disintegration of groups or chain segments, resulting in a slow and lengthy disintegration process.

[0005] Therefore, developing a liquid metal transient circuit that does not rely on substrate decomposition, has a fast response decomposition speed, and is simple to construct has important application value. Summary of the Invention

[0006] To address the shortcomings of current transient circuits, this invention provides a liquid metal transient circuit, its preparation method, and its application. The aim is to achieve simple and low-cost construction of transient circuits by combining liquid metal with a second-phase material to form a non-Newtonian fluid slurry, while improving the response decomposition speed of the transient circuit.

[0007] In a first aspect, the present invention provides a liquid metal transient circuit.

[0008] A liquid metal transient circuit is disclosed, wherein the liquid metal transient circuit is constructed by printing or brushing liquid metal slurry, wherein the liquid metal slurry is a composite material with non-Newtonian fluid properties formed by combining liquid metal and a second phase material; the liquid metal transient circuit, either as a whole or in part, can rapidly disintegrate under the action of stimulus conditions.

[0009] Furthermore, the liquid metal is selected from one or more of gallium, indium, tin, zinc, and bismuth, and consists of mono- to pentagonal alloys with melting points below 100°C.

[0010] Furthermore, the second phase material is selected from one or more microparticles of aluminum, magnesium and their alloys, or from one or more microparticles of polyvinyl alcohol, lactic acid-glycolic acid copolymer, polyanhydride, and polyhydroxyalkanoate.

[0011] Furthermore, the mass ratio of the second phase substance to the liquid metal in the liquid metal slurry is 1% to 50% : 1.

[0012] Furthermore, the stimulation condition is the application of one or more of an acid solution, an alkaline solution, a salt solution, water, or an alcohol solution.

[0013] Furthermore, the thickness of the liquid metal transient circuit is 1μm to 100μm, and the width is 1μm to 5mm.

[0014] The circuit may or may not contain other electronic components besides the liquid metal paste conductive path, and may or may not contain a surface encapsulation layer. The substrate or support may or may not decompose under the same stimulating conditions.

[0015] Secondly, the present invention provides a method for preparing a liquid metal transient circuit.

[0016] A method for fabricating a liquid metal transient circuit includes the following steps: Step 1: Select liquid metal and second-phase material; Step 2: The second phase material is uniformly dispersed and mixed into the liquid metal matrix by mechanical stirring or vibration to obtain a liquid metal slurry with non-Newtonian fluid properties; Step 3: Based on the circuit function and failure conditions, design the structure of the liquid metal transient circuit; Step 4: Using a planar printing or three-dimensional spatial printing device, apply the liquid metal paste to the substrate surface or inside the support body according to the circuit structure designed in Step 3 to construct a liquid metal transient circuit.

[0017] Furthermore, the preparation of the liquid metal slurry in step two is carried out in an inert gas atmosphere with a water content and oxygen content of less than 0.1 ppm.

[0018] Furthermore, in the liquid metal transient circuit constructed in step four, the line thickness is 1μm to 100μm and the line width is 1μm to 5mm.

[0019] Furthermore, step four further includes adding a surface encapsulation layer to the constructed liquid metal transient circuit, or adding other electronic devices besides the liquid metal slurry conductive path.

[0020] Thirdly, the present invention provides an application of a liquid metal transient circuit.

[0021] An application of a liquid metal transient circuit includes the liquid metal transient circuit described in any of the preceding claims, or the liquid metal transient circuit prepared by the method described in any of the preceding claims.

[0022] Compared with the prior art, the present invention has the following beneficial effects: This invention combines the conductivity and fluid properties of liquid metal with a suitable second-phase material to prepare a paste with non-Newtonian fluid properties. This allows for easy printing and construction of circuit patterns, is simple to operate, low in cost, and offers a high degree of freedom in circuit design and control, making it adaptable to large-scale applications in specific fields.

[0023] The liquid metal transient circuit provided by this invention does not rely on the decomposition of the substrate material, but is based on the rapid disintegration of the liquid metal circuit itself, which has a faster response and decomposition speed compared with traditional liquid metal transient circuits that rely on the degradation of the substrate material.

[0024] This invention enables controllable adjustment of the disintegration speed by regulating the types and ratios of liquid metal and second-phase materials, as well as the geometric dimensions of the circuit, thus meeting the transient response time requirements of different application scenarios.

[0025] The transient circuit obtained by this invention has a thickness of 1μm to 100μm and a width of 1μm to 5mm. After disintegration under stimulation, the traces of the circuit are invisible to the naked eye, making it suitable for fields with high requirements for trace concealment, such as information security and anti-counterfeiting.

[0026] The preparation method provided by this invention is simple and efficient, requires no complex equipment, and is suitable for large-scale production and widespread application. Attached Figure Description

[0027] To more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings used in the following description of the embodiments will be briefly introduced. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0028] Figure 1 The figure shows the rheological test results of the liquid metal slurry in Example 1 of the present invention; Figure 2 This is a circuit diagram designed according to the circuit function and failure conditions in Embodiment 1 of the present invention; Figure 3 This is a schematic diagram and a physical image of the liquid metal transient circuit constructed in Embodiment 1 of the present invention triggering transient behavior under external stimuli. Figure 4 This is a physical diagram of the liquid metal transient circuit constructed in Embodiment 3 of the present invention, showing the transient nature triggered by external stimuli. Detailed Implementation

[0029] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention. Unless otherwise defined, the technical or scientific terms used herein should have the ordinary meaning understood by those skilled in the art. The terms "comprising" and similar expressions used herein mean that the element or object preceding the word covers the element or object listed after the word and its equivalents, but does not exclude other elements or objects.

[0030] This invention provides a liquid metal transient circuit, the construction method of which is as follows: Select a liquid metal and a suitable second phase material; wherein the liquid metal is selected from one of the mono- to pent-element alloys with a melting point of less than 100°C composed of gallium, indium, tin, zinc, and bismuth; and the second phase material is selected from one or more particles of aluminum, magnesium and their alloys and / or polyvinyl alcohol (PVA), lactic acid-glycolic acid copolymer (PLGA), polyanhydride, and polyhydroxyalkanoate (PHA). The second phase material is uniformly dispersed and mixed into the liquid metal matrix by mechanical stirring or vibration to obtain a liquid metal slurry with non-Newtonian fluid properties, wherein the mass ratio of the two components is 1%~50%:1.

[0031] Based on circuit function and failure conditions, design the structure of a liquid metal transient circuit; Using planar printing or three-dimensional spatial printing equipment, liquid metal paste is applied to the surface of the substrate or the interior of the support according to the circuit structure design to construct the circuit. The parameters of the circuit are as follows: thickness is 1μm-100μm, and width is 1μm-5mm. Depending on the actual functional requirements, other electronic devices besides the liquid metal paste conductive path can be optionally added to the circuit constructed in the above steps, and a surface encapsulation layer can be optionally applied.

[0032] The resulting transient circuit, either as a whole or in part, can rapidly disintegrate under appropriate stimulus conditions, which are one or more of the following: acid, alkali, salt solution, water, and alcohol solution.

[0033] A second objective of this invention is to provide an application of the above-described liquid metal transient circuit.

[0034] The technical effects of the present invention will be described below with reference to specific embodiments. Example

[0035] Gallium-indium binary alloy was selected as the matrix, and 5μm aluminum powder was selected as the second phase material; Aluminum powder, comprising 10% of the mass of the gallium-indium alloy, was uniformly dispersed and mixed into a gallium-indium alloy matrix using mechanical stirring to prepare a liquid metal slurry. The rheological properties of this slurry are as follows: Figure 1 As shown, its elastic modulus G' > loss modulus G'', and it exhibits shear thinning (the higher the shear frequency, the lower the complex viscosity), making it a typical non-Newtonian fluid material; The desired outcome is a circuit that can conduct and transfer electrical energy for a period of time, but disintegrates under the stimulus of rising water levels after it is no longer needed. Therefore, the structure of a liquid metal transient circuit is designed, such as... Figure 2 As shown; Non-Newtonian fluid slurries are suitable for printing, coating, and other operations, utilizing stencil printing methods, according to... Figure 2 The designed circuit structure involves coating a PET substrate with liquid metal paste to construct the circuit. The circuit is 40μm thick and 2mm wide, and an LED bulb is installed at the break point in the circuit without applying a surface encapsulation layer.

[0036] like Figure 3 As shown, the resulting transient circuit works normally when there is no water, and the bulb lights up; however, when the water level rises and touches the transient circuit wires, the corresponding wires quickly disintegrate and fail (within 5 seconds), causing the bulb in that circuit to go out. This transient circuit can be used for water level warning. Example

[0037] The only difference from Example 1 is that the mass ratio of aluminum powder to gallium-based liquid metal in this example is 30%:1, and the gallium-based liquid metal is selected from gallium-indium-tin ternary alloy. The other processes are the same as in Example 1, and will not be repeated here. Example

[0038] The only difference from Example 2 is that the substrate for the liquid metal transient circuit printing in this example is a 40μm thick water-soluble polyvinyl alcohol (PVA). This means the transient nature of the circuit can be determined simultaneously by the degradation of both the substrate material and the liquid metal circuitry. Everything else is the same as in Example 2 and will not be repeated here. The degradation process of this transient circuit upon contact with water is as follows... Figure 4 As shown.

[0039] In summary, this invention, based on the combination of the conductivity and fluid properties of liquid metal, a novel material, and the non-Newtonian fluid slurry obtained by combining it with a suitable second-phase material, can easily realize the printing and construction of circuit patterns. It is simple to operate, low in cost, and offers a high degree of freedom in circuit design and control, making it flexibly adaptable to large-scale applications in specific fields. The liquid metal transient circuit disassembly provided by this invention does not depend on the decomposition of the substrate material, exhibiting a faster response and disassembly speed compared to liquid metal transient circuits constructed using traditional methods.

[0040] While embodiments of the present invention have been described in detail above, it will be apparent to those skilled in the art that various modifications and variations can be made to these embodiments. However, it should be understood that such modifications and variations fall within the scope and spirit of the invention as set forth in the claims. Furthermore, the invention described herein may have other embodiments and can be implemented or carried out in various ways.

Claims

1. A liquid metal transient circuit, characterized in that, The liquid metal transient circuit is constructed by printing or brushing liquid metal slurry, which is a composite material with non-Newtonian fluid properties formed by combining liquid metal and a second-phase substance; the liquid metal transient circuit, either as a whole or in part, can rapidly disintegrate under stimulating conditions.

2. The liquid metal transient circuit according to claim 1, characterized in that, The liquid metal is selected from one or more of gallium, indium, tin, zinc, and bismuth, and consists of mono- to pent-element alloys with melting points below 100°C.

3. The liquid metal transient circuit according to claim 1, characterized in that, The second phase material is selected from one or more microparticles of aluminum, magnesium and their alloys, or from one or more microparticles of polyvinyl alcohol, lactic acid-glycolic acid copolymer, polyanhydride and polyhydroxy fatty acid ester.

4. The liquid metal transient circuit according to claim 1, characterized in that, The mass ratio of the second phase material to the liquid metal in the liquid metal slurry is 1% to 50%:

1.

5. A liquid metal transient circuit according to claim 1, characterized in that, The stimulation condition is the application of one or more of an acid solution, an alkaline solution, a salt solution, water, or an alcohol solution.

6. A liquid metal transient circuit according to claim 1, characterized in that, The thickness of the liquid metal transient circuit is 1μm to 100μm, and the width is 1μm to 5mm.

7. A method for fabricating a liquid metal transient circuit, characterized in that, Includes the following steps: Step 1: Select liquid metal and second-phase material; Step 2: The second phase material is uniformly dispersed and mixed into the liquid metal matrix by mechanical stirring or vibration to obtain a liquid metal slurry with non-Newtonian fluid properties; Step 3: Based on the circuit function and failure conditions, design the structure of the liquid metal transient circuit; Step 4: Using a planar printing or three-dimensional spatial printing device, apply the liquid metal paste to the substrate surface or inside the support body according to the circuit structure designed in Step 3 to construct a liquid metal transient circuit.

8. The method for fabricating a liquid metal transient circuit according to claim 7, characterized in that, The preparation of the liquid metal slurry in step two is carried out in an inert gas atmosphere with both water content and oxygen content less than 0.1 ppm.

9. The method for fabricating a liquid metal transient circuit according to claim 7, characterized in that, In the liquid metal transient circuit constructed in step four, the line thickness is 1μm to 100μm and the line width is 1μm to 5mm.

10. An application of a liquid metal transient circuit, characterized in that, It includes the liquid metal transient circuit according to any one of claims 1 to 6, or the liquid metal transient circuit prepared by the method according to any one of claims 7 to 9.

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