A modified liquid metal and its use in the production of liquid metal patterns

Abstract

This invention discloses a modified liquid metal and its use in preparing liquid metal patterns, belonging to the field of metal pattern preparation technology. The modified liquid metal of this invention is composed of liquid metal and sodium magnesium lithium silicate in a mass ratio of 4-10:1. The addition of sodium magnesium lithium silicate significantly reduces the surface tension and improves the adhesion of the liquid metal, facilitating the formation of fine and stable micropatterns on the substrate surface. The liquid metal micropatterns prepared using the modified liquid metal of this invention exhibit excellent conductivity under bending and stretching conditions, showing promising application prospects in the field of flexible sensors.

Description

Technical Field

[0001] This invention relates to the field of metal pattern preparation technology, and in particular to a modified liquid metal and its use in preparing liquid metal patterns. Background Technology

[0002] In recent years, with the advent of the mobile internet era, smart wearable devices have become a model of the integration of mobile internet hardware and software. Meanwhile, the continuous iteration and upgrading of big data, cloud computing, and IoT technologies have greatly expanded the development space for smart wearable devices. Flexible sensors, as one of the core components, have become a key research direction for future smart devices due to their high sensitivity and spatial resolution, wide detection range, short response time, user comfort, and multifunctional integration.

[0003] Liquid metals are ideal electrode materials for flexible sensor fabrication due to their excellent conductivity, superior ductility, and good biocompatibility. Among them, gallium and its alloys are currently the most actively researched room-temperature liquid metal materials. Patterning of liquid metals is a prerequisite for their application in flexible sensors, but their high surface tension and weak wettability make forming circuit patterns on substrate surfaces extremely challenging.

[0004] Therefore, conducting research and technological innovation on liquid metal micropattern fabrication methods, and mastering the fabrication methods and processes for liquid metal sensor devices with adjustable structure and performance, is a very important and scientifically challenging research endeavor.

[0005] Currently, methods for patterning liquid metal mainly include direct-write printing, microchannel injection, and screen printing / stencil printing. Direct-write printing has lower requirements for the substrate material, but the high surface tension of liquid metal and the presence of a surface oxide layer result in poor accuracy and stability of the micropatterns produced by this method. Microchannel injection can avoid the formation of a surface oxide layer, but the complexity and accuracy of the prepared patterns depend on the complexity and accuracy of the microchannels. Screen printing / stencil printing involves cumbersome and time-consuming operations, and each pattern requires a corresponding stencil, resulting in high costs. The limitations of these methods hinder the widespread application of liquid metals. Summary of the Invention

[0006] To address the aforementioned problems, this invention provides a novel modified liquid metal. Applying this modified liquid metal to the preparation of micropatterns overcomes the shortcomings of conventional techniques, such as low controllability of micropattern structures, poor performance stability, and strong dependence on substrate materials, and has significant advantages.

[0007] To solve the above-mentioned technical problems, the present invention provides the following technical solution:

[0008] A modified liquid metal is composed of liquid metal and sodium magnesium lithium silicate in a mass ratio of 4-10:1.

[0009] The above-mentioned modified liquid metal, by adding sodium magnesium lithium silicate, can greatly reduce the surface tension of the liquid metal and improve its adhesion, which helps the modified liquid metal to form fine and stable micro-patterns on the substrate surface.

[0010] In some of these embodiments, the liquid metal is gallium or a gallium alloy, preferably a gallium alloy, such as a gallium-indium alloy; further, the gallium-indium alloy is an alloy of 70-80% gallium and 20-30% indium, preferably an alloy of 75% gallium and 25% indium.

[0011] In some of these embodiments, the sodium magnesium lithium silicate is in the form of solid granules. Preferably, the particle size of the sodium magnesium lithium silicate is less than 100 μm, for example: less than 50 μm, less than 20 μm, less than 10 μm, less than 1 μm, less than 100 nm, or less than 10 nm.

[0012] In some of these schemes, the mass ratio of liquid metal to sodium magnesium lithium silicate is 4-7:1, preferably 4.5-5.5:1, and more preferably 5:1. It is understood that within a certain mass ratio range, as the amount of sodium magnesium silicate added increases, the adhesion of the resulting modified liquid metal increases and its fluidity decreases. However, if the ratio exceeds a certain limit, and the amount of liquid metal cannot completely encapsulate the sodium magnesium lithium silicate, the sodium magnesium lithium silicate powder particles occupy the main body, losing adhesion and even becoming non-conductive. Modified liquid metals proportioned within the above range can basically meet the requirements for micropattern preparation; however, a 5:1 ratio is the optimal ratio for compatibility with the PDMS substrate.

[0013] On the other hand, the present invention also provides a method for preparing the above-mentioned modified liquid metal, comprising the following steps: adding the liquid metal to an organic solvent, ultrasonically treating the liquid metal to form particles, collecting the lower layer of liquid metal particles; and mixing the liquid metal particles with the sodium magnesium lithium silicate to obtain the product.

[0014] The above preparation method utilizes ultrasound to break down and disperse liquid metal into small liquid metal particles in an organic solvent, increasing its oxide layer area. The mixture is then mixed with sodium magnesium lithium silicate, causing the sodium magnesium lithium silicate to be encapsulated by the metal particles, forming a modified liquid metal. This significantly reduces the surface tension of the liquid metal and improves its adhesion. Furthermore, the resulting modified liquid metal has a high liquid metal content, making it recyclable and self-healing.

[0015] In some of these solutions, the organic solvent is at least one of acetone and anhydrous ethanol, preferably acetone. It is understood that the aforementioned organic solvent serves as a dispersion medium, promoting the formation of particles from liquid metal under ultrasonic action. The solvent can be selected according to actual needs, and acetone, as a common, highly volatile solvent in laboratories, has the advantages of good performance, ease of operation, and low cost.

[0016] In some of these schemes, the ratio of liquid metal to organic solvent is 0.5-2.5g liquid metal: 10-50mL organic solvent, preferably 1-1.7g liquid metal: 20-40mL organic solvent, and more preferably 1.35g liquid metal: 30mL organic solvent.

[0017] In some of these schemes, the conditions for ultrasonic treatment are: ultrasonication with an amplitude of 50-80 mm for 10-30 minutes; preferably, a probe ultrasonic device is used, and ultrasonication with an amplitude of 64 mm is performed for 20 minutes.

[0018] In some of these schemes, after the ultrasonic treatment is completed, the liquid metal particles are obtained by centrifugation.

[0019] In some of these schemes, the centrifugation conditions are centrifugation at 1500-3000 rap for 10-50 min, preferably centrifugation at 2200 rap for 30 min.

[0020] In some of these schemes, the liquid metal particles are mixed evenly with the sodium magnesium lithium silicate by stirring.

[0021] On the other hand, the present invention also provides the use of the above-mentioned liquid metal in the preparation of liquid metal patterns.

[0022] On the other hand, the present invention also provides a method for preparing liquid metal patterns, comprising the following steps:

[0023] Preparation of dry film pattern: Prepare a dry film pattern on the surface of the substrate to which the dry film has been adhered;

[0024] Preparation of liquid metal pattern: The above-mentioned liquid metal is attached to the surface of a substrate with a dry film pattern, and the dry film is removed to obtain the liquid metal pattern.

[0025] With the development of surface patterning technology and the innovative application of patterned surfaces, the technique of inducing liquid metal patterning by utilizing the differences in physical or chemical properties of different regions of a patterned surface has received attention and development. Therefore, dry film patterns can be prepared on dry films using the above principles. Furthermore, taking advantage of the low surface tension and high viscosity of the modified liquid metal of this invention, the modified liquid metal is attached to the exposed substrate surface of the dry film pattern. Utilizing the silicon-oxygen bonds and oxide film formed between the liquid metal and the substrate surface, no further sintering or curing is required; simply peeling off the dry film completes the preparation of the liquid metal pattern.

[0026] Furthermore, the liquid metal of the present invention, without the need to add resin or other components, can achieve a pattern precision at the μm level by adding sodium magnesium lithium silicate, while maintaining a high proportion of liquid metal content, which has significant advantages.

[0027] In some of these schemes, a substrate surface activation step is included before the dry film patterning step. The substrate surface activation step is as follows: the cleaned substrate is placed in a cleaning agent, ultrasonically treated, and then cleaned sequentially with anhydrous ethanol and deionized water. Finally, the surface is subjected to plasma treatment to obtain the activated substrate.

[0028] In some of these solutions, the cleaning agent is an aqueous solution of glass.

[0029] In some of these solutions, the substrate is made of at least one of planar or curved materials, rigid materials, and flexible materials.

[0030] In some of these solutions, the substrate is a flexible substrate made of a flexible material.

[0031] In some of these embodiments, the substrate material is an inorganic or organic material; further, the inorganic material is at least one of a metal or its alloy, a metal oxide, or a silicon-containing inorganic non-metallic material; the organic material is a synthetic or natural material, and even further, the synthetic material is at least one of plastics, rubber, and fibers, and the natural material is at least one of wood and leaves.

[0032] In some of these schemes, the substrate is a PDMS (polydimethylsiloxane) substrate.

[0033] In some of these schemes, the dry film is a photosensitive film, and the dry film patterning step involves selectively irradiating the photosensitive dry film to obtain the dry film pattern. This selective irradiation can be achieved using a maskless lithography system based on a DMD (Digital Micro-mirror Device) spatial light modulator, allowing the fabrication of photosensitive dry film patterns of arbitrary shapes on the surface of a substrate material. Irradiation of the photosensitive dry film surface can selectively induce a chemical reaction in the photosensitizer, subsequently dissolving the unreacted dry film to obtain the dry film pattern.

[0034] In some of these schemes, the dry film pattern is obtained by developing the irradiated dry film in a developer to obtain the dry film pattern.

[0035] Understandably, the above-mentioned dry film and developing methods can be achieved using photosensitive dry films commonly used in this field and corresponding conventional developing methods.

[0036] In some of these schemes, the liquid metal patterning step involves applying the liquid metal to the substrate surface using a scraping method.

[0037] In some of these schemes, the PDMS substrate is prepared by mixing a PDMS prepolymer and a curing agent evenly, curing, and cutting it to a predetermined size.

[0038] In some of these schemes, the PDMS substrate is prepared by mixing PDMS prepolymer and curing agent Sylgard184 at a mass ratio of 8-12:1, first refrigerating at 3-7°C to remove air bubbles, then curing at 60-100°C, and cutting to a predetermined size.

[0039] In some of these schemes, the PDMS substrate is prepared by mixing PDMS prepolymer and curing agent Sylgard184 at a mass ratio of 10:1, first refrigerating at 5°C to remove air bubbles, and then curing at 80°C.

[0040] In some of these schemes, the substrate surface activation step involves first immersing the substrate in anhydrous ethanol and then in deionized water for ultrasonic cleaning, followed by treatment in a cleaning agent.

[0041] In some of these embodiments, during the substrate surface activation step, the aqueous glass solution is a mixed solution of deionized water and water glass in a volume ratio of 7-11:1, preferably 9:1.

[0042] In some of these schemes, the plasma treatment in the substrate surface activation step is performed using a plasma surface treatment machine.

[0043] In some of these schemes, the selective irradiation conditions in the dry film patterning step are: wavelength of 400-410 nm, for example 405 nm, exposure time of 3-10 min, for example 5 min, and power of 5-15 W, for example 10 W.

[0044] In some of these embodiments, the developer in the developing step is an aqueous solution of Na2CO3, preferably a 0.5-3% aqueous solution of Na2CO3, such as a 1.0% aqueous solution of Na2CO3, and the developing time is 60-120 s, preferably 90 s.

[0045] In some of these embodiments, during the step of preparing the liquid metal pattern, the coating thickness of the liquid metal is 0.01-0.5 mm, preferably 0.1-0.3 mm, and more preferably 0.2 mm.

[0046] The present invention also provides a flexible sensor, comprising a flexible substrate and a liquid metal pattern attached to the flexible substrate, wherein the liquid metal pattern is prepared from the modified liquid metal described above.

[0047] In some of these solutions, the flexible substrate is a flexible substrate made of PDMS, glass, or hydrogel, for example, a PDMS flexible substrate.

[0048] In some of these schemes, the thickness of the liquid metal pattern is 0.01-0.5 mm, more specifically 0.1-0.3 mm, for example 0.2 mm.

[0049] On the other hand, the present invention also provides a method for preparing the above-mentioned flexible sensor, comprising the following steps: encapsulating a flexible substrate having a liquid metal pattern, thereby obtaining the sensor.

[0050] In some of these schemes, the encapsulation step involves coating the surface of the flexible substrate with a substrate material prepolymer and then curing it to prepare the encapsulation layer.

[0051] In some of these solutions, the thickness of the encapsulation layer is 0.01-0.5 mm, more specifically 0.1-0.3 mm, for example 0.2 mm.

[0052] Based on common knowledge in the field, the above-mentioned preferred conditions can be combined arbitrarily to obtain various preferred embodiments of the present invention.

[0053] The reagents and raw materials used in this invention are all commercially available.

[0054] The positive and progressive effects of this invention are as follows:

[0055] The present invention discloses a modified liquid metal, which reduces the surface tension of the liquid metal by adding sodium magnesium lithium silicate. This helps to solve the problems of low precision in patterning, high fluidity, weak adhesion, and serious leakage of liquid metal. It also has self-healing and recyclability, which is conducive to promoting the practical application of liquid metal.

[0056] The method for preparing liquid metal patterns according to the present invention does not require the fabrication of a template. Patterns can be prepared by selective irradiation onto a dry film, such as using a maskless lithography system with a DMD spatial light modulator. The image can be designed autonomously via software. To prepare liquid metal micropatterns of different shapes or sizes, the corresponding pattern only needs to be designed and loaded onto the DMD controller. Compared with traditional methods requiring template fabrication (e.g., flatbed printing, microfluidic injection), the preparation method of the present invention has advantages such as simplicity, controllable process, and potential for large-scale industrial application. It can be used to prepare high-precision liquid metal patterns. Furthermore, this method is simple, material-saving, and environmentally friendly, and has broad application prospects in flexible electronic devices.

[0057] The present invention discloses a flexible sensor that exhibits excellent conductivity under bending and stretching conditions by fabricating liquid metal micropatterns with good flexibility on a flexible substrate (such as a PDMS substrate). Attached Figure Description

[0058] Figure 1 This is a flowchart of the fabrication of liquid metal micropatterns based on maskless photolithography.

[0059] Figure 2 This is a schematic diagram of liquid metal forming nanoparticles under the influence of an acoustic field.

[0060] Figure 3 The images show SEM images of the modified liquid metal before and after the addition of sodium magnesium lithium silicate.

[0061] Figure 4 This is a SEM image of the modified liquid metal after the addition of sodium magnesium lithium silicate.

[0062] Figure 5 Optical microscope images of photosensitive dry film patterns and liquid metal patterns on PDMS substrate surfaces.

[0063] Figure 6 This is a schematic diagram of the flexible sensor structure in Example 2.

[0064] Figure 7 This is a physical image of the flexible pressure sensor prepared in Example 2.

[0065] Figure 8 The graph shows the change in resistance of the flexible sensor in Experiment Example 1 over time under pressure.

[0066] Figure 9 The graph shows the resistance change of the flexible sensor in Experiment Example 1 during the stretching process.

[0067] Figure 10 This is a schematic diagram of recyclability in Experiment Example 2.

[0068] Figure 11 This is a schematic diagram of the self-healing mechanism in Experiment Example 3.

[0069] Figure 12 This is the transistor-based running light circuit in Experiment Example 4.

[0070] Figure 13 This is a SEM image of the liquid metal pattern in Experiment Example 4. Detailed Implementation

[0071] The present invention is further illustrated below by way of embodiments, but the invention is not limited to the scope of the embodiments described herein. Experimental methods in the following embodiments that do not specify specific conditions were performed according to conventional methods and conditions, or as selected according to the product instructions.

[0072] Example 1

[0073] A method for fabricating liquid metal micropatterns on flexible substrate surfaces, the process flow of which is as follows: Figure 1 As shown, it includes the following steps:

[0074] S1: Flexible substrate fabrication

[0075] (1) Mix PDMS prepolymer (CAS#:9016-00-6, source: Dow Corning-PDMS184) and curing agent (model: Sylgard184, manufacturer: Dow Corning) at a mass ratio of 10:1, and stir rapidly with a glass rod for 15 minutes to ensure that the curing agent and prepolymer are mixed evenly.

[0076] (2) Place the mixed PDMS prepolymer in a refrigerator at 5°C for 2 hours to remove the air bubbles generated during stirring, and then cure it at 80°C for 4 hours.

[0077] (3) Cut the cured PDMS film into substrates of a specific size, wash with ethanol and deionized water, and dry in an oven to obtain the PDMS substrate.

[0078] S2: PDMS substrate surface activation treatment

[0079] (1) The PDMS substrate was placed in anhydrous ethanol and deionized water in sequence for ultrasonic cleaning and then dried.

[0080] (2) The cleaned PDMS substrate was placed in a mixed solution of deionized water and glass water (volume ratio 9:1) for cleaning. After ultrasonic vibration for 3 minutes, it was cleaned sequentially with anhydrous ethanol and deionized water. Then, it was treated with a plasma surface treatment machine with the following parameters: input power supply AC220V / 50Hz, gas flow rate 10-30L / min, and gas pressure 0.5-4 kg / cm³. 2 (Compressed air) is used to process PDMS substrates at a speed of 10-500 mm / s.

[0081] S3: Preparation of photosensitive dry film patterns on PDMS substrate surface

[0082] (1) A photosensitive dry film (ETERTEC: HT-115T) is pasted onto the surface of the activated PDMS substrate.

[0083] (2) A beam pattern is generated on its projection plane by means of a maskless lithography system based on a DMD spatial light modulator (such as disclosed in CN 201910831350.5).

[0084] (3) Place the PDMS substrate with the photosensitive dry film attached on the projection plane of the maskless photolithography system and expose it for 10 min. Then develop it in the developer (1% Na2CO3) for 90 s to obtain a PDMS substrate with a photosensitive dry film pattern on the surface.

[0085] S4: Liquid metal modification

[0086] (1) Liquid metal (gallium-indium alloy, 1.35 g, containing 75% gallium and 25% indium, purchased from: Huatai Metal) was added to acetone (30 mL) solvent. The mixture was sonicated for 20 min at an amplitude of 64 mm (44%) using a probe sonicator. After centrifugation at 2200 rpm for 30 min, a layered solution was obtained. The upper solvent layer was removed, and the lower liquid layer was collected to obtain liquid metal particles, such as… Figure 2 As shown in the figure, the liquid metal is transformed into a nanoparticle with uneven particle size under the action of an acoustic field. Due to the presence of an oxide layer, the smaller particles will stick to the surface of the larger particles.

[0087] (2) 2g of sodium magnesium lithium silicate (CAS: 53320-86-8, particle size 10-20μm) and 10g of liquid metal particles were added to a beaker and stirred with a glass rod for 20min to obtain modified liquid metal. SEM images of this modified liquid metal before and after the addition of sodium magnesium lithium silicate are shown below. Figure 3 As shown, where, Figure 3 The left and right images are SEM images of liquid metal before and after mixing with sodium magnesium lithium silicate, respectively. The comparison of the images shows that mixing with sodium magnesium lithium silicate increases the oxide layer area of ​​the liquid metal.

[0088] Figure 4 The image shows a SEM image of the modified liquid metal after the addition of sodium magnesium lithium silicate. As can be seen from the image, the surface of the sodium magnesium lithium silicate coated with liquid metal also shows an increased oxide layer.

[0089] S5: Liquid Metal Patterning

[0090] (1) A layer of modified liquid metal with a thickness of 0.2 mm was scraped onto the surface of the PDMS substrate on which the photosensitive dry film pattern was prepared.

[0091] (2) After peeling off the photosensitive dry film used as a template, liquid metal micropatterns are obtained on the surface of the PDMS substrate.

[0092] Figure 5In the middle (a) and (b), optical microscope images of the photosensitive dry film pattern and liquid metal pattern on the surface of the PDMS substrate prepared in this embodiment are respectively.

[0093] Example 2

[0094] A flexible pressure sensor based on liquid metal micropatterns is fabricated by the following method:

[0095] S1: Fabrication of Ring-shaped Liquid Metal Micropatterns

[0096] Annular liquid metal micropatterns were prepared on the surface of a PDMS substrate using the method described in Example 1.

[0097] S2: PDMS packaging

[0098] (1) A PDMS prepolymer with a thickness of 0.2 mm was uniformly spin-coated onto the surface of a PDMS substrate containing annular liquid metal micropatterns.

[0099] (2) After curing at 80℃ for 4 hours, a flexible pressure sensor based on liquid metal micropatterns was obtained, the structure of which is as follows: Figure 6 As shown, an encapsulation layer, a sensing layer, and a substrate are stacked sequentially, with liquid metal micropatterns located in the sensing layer. This flexible pressure sensor is shown in the image. Figure 7 As shown.

[0100] Experimental Example 1

[0101] The electrical performance of the flexible sensor prepared in Example 2 was tested.

[0102] 1. Method

[0103] (1) Pressing process: Using a data acquisition device of model 2700, the device moves forward 8 steps and backward 8 steps at a speed of 1 mm / s on an electric displacement stage, repeating this process to simulate the pressing process and measure the change in resistance over time.

[0104] (2) Stretching process: The stretching process uses a stretching displacement stage. Each stretching is 10% deformation, and then the deformation is restored. The stretching-restoring cycle is repeated rapidly. The corresponding resistance is read using a data acquisition device to obtain the data and generate a resistance-time graph.

[0105] 2. Results

[0106] Electrical performance results are as follows Figure 8 As shown in the figure, the resistance changes are very sensitive during the pressing process. The pressing process lasts for 8 seconds, the rising process in the figure also lasts for 8 seconds, and the falling process is also stable at around 8 seconds, which shows that the flexible sensor is quite sensitive to the pressing process.

[0107] The resistance-strain condition under tension is as follows: Figure 9As shown in the figure, the resistance changes rapidly during the rapid and repeated stretching-recovery process. The resistance is sensitive to the stretching changes and can recover quickly, making it quite sensitive to the stretching process.

[0108] Experiment Example 2

[0109] The liquid metal pattern prepared according to the method in Example 1 can be used to obtain liquid metal spheres in a very short time (about 1 second) by adding an appropriate amount of 5% sodium hydroxide solution to the pattern at room temperature without special conditions, thus achieving the purpose of recycling.

[0110] The recycling process is as follows Figure 10 As shown in the figure, A represents the state before the addition of sodium hydroxide solution, B represents the state after the addition of sodium hydroxide solution, and C represents the state of liquid metal automatically agglomerating into small spheres.

[0111] Experimental Example 3

[0112] The liquid metal pattern prepared according to the method in Example 1 was used to fabricate a circuit. Figure 9 The process shown involves using a needle to pierce the circuit. Figure 11 In case A), when powered on, the small light did not turn off, the brightness did not change significantly, and there was no leakage of liquid metal. Figure 11 (C). Then use scissors to cut the circuit; after cutting, the light goes out. Figure 11 (B) allows the PDMS substrate to automatically return to its original state. The circuit automatically repairs itself in a very short time, the circuit is restored, and the small LED lights up. Figure 11 (D).

[0113] The aforementioned liquid metal patterns exhibit restorative properties because the prepared liquid metal has strong adhesive properties, causing it to flow and stick together, thereby achieving the purpose of repair.

[0114] Experiment Example 4

[0115] Fabrication of 180-270µm linewidth metal patterns

[0116] More complex metal patterns with widths of 180-270 μm were prepared according to the method in Example 1, such as... Figure 12 As shown, A represents the prepared metal pattern, and B represents the flexible circuit obtained from the metal pattern. The above results demonstrate that the micropatterns prepared from the modified liquid metal of this invention can guarantee a circuit linewidth of 200 μm, making them practically applicable to flexible circuit boards, rather than merely remaining theoretically feasible.

[0117] Furthermore, the above pattern was observed under an optical microscope, and the results were as follows: Figure 13 As shown in the figure, A and B are magnified 20 times and 50 times respectively, indicating that the lines of the pattern are full and stable.

Claims

1. A modified liquid metal, characterized in that, It consists of liquid metal and sodium magnesium lithium silicate in a mass ratio of 4-10:

1.

2. The modified liquid metal as described in claim 1, characterized in that, The liquid metal is gallium or a gallium alloy, preferably a gallium alloy, such as a gallium-indium alloy; further, the gallium-indium alloy is an alloy of 70-80% gallium and 20-30% indium, preferably an alloy of 75% gallium and 25% indium; and / or The sodium magnesium lithium silicate is in solid particulate form. Preferably, the particle size of the sodium magnesium lithium silicate is less than 100 μm, for example: less than 50 μm, less than 20 μm, less than 10 μm, less than 1 μm, less than 100 nm, less than 10 nm. and / or The mass ratio of the liquid metal to sodium magnesium lithium silicate is 4-7:1, preferably 4.5-5.5:1, and more preferably 5:

1.

3. The method for preparing the modified liquid metal according to claim 1 or 2, characterized in that, Includes the following steps: The liquid metal is added to an organic solvent and ultrasonically treated to form granules. The lower layer of liquid metal granules is collected. The liquid metal granules are then mixed evenly with sodium magnesium lithium silicate to obtain the final product.

4. The method for preparing the modified liquid metal according to claim 3, characterized in that, Meets at least one of the following conditions: (1) The organic solvent is at least one of acetone and anhydrous ethanol, preferably acetone; (2) The ratio of liquid metal to organic solvent is 0.5-2.5g liquid metal: 10-50mL organic solvent, preferably 1-1.7g liquid metal: 20-40mL organic solvent, and more preferably 1.35g liquid metal: 30mL organic solvent; (3) The conditions for ultrasonic treatment are: ultrasonic treatment with an amplitude of 50-80 mm for 10-30 min; preferably, a probe ultrasonic device is used, and ultrasonic treatment with an amplitude of 64 mm for 20 min. (4) After the ultrasonic treatment is completed, the liquid metal particles are obtained by centrifugation. Preferably, the centrifugation conditions are centrifugation at 1500-3000 rap for 10-50 min, and more preferably centrifugation at 2200 rap for 30 min. (5) The liquid metal particles and the sodium magnesium lithium silicate are mixed evenly by stirring.

5. Use of the liquid metal according to claim 1 or 2 in the preparation of liquid metal patterns.

6. A method for preparing liquid metal patterns, characterized in that, Includes the following steps: Preparation of dry film pattern: Prepare a dry film pattern on the surface of the substrate to which the dry film has been adhered; Preparation of liquid metal pattern: Attach the liquid metal of claim 1 or 2 to the surface of a substrate with a dry film pattern, and remove the dry film to obtain the liquid metal pattern.

7. The method for preparing liquid metal patterns as described in claim 6, characterized in that, Meets at least one of the following conditions: (1) Before the dry film pattern preparation step, a substrate surface activation step is also included. The substrate surface activation step is as follows: the cleaned substrate is placed in a cleaning agent, ultrasonically treated, and then cleaned with anhydrous ethanol and deionized water in sequence, and then its surface is subjected to plasma treatment to obtain the activated substrate; the cleaning agent is, for example, a glass aqueous solution. (2) The material of the substrate is at least one of planar material or curved material, rigid material and flexible material, and the substrate is preferably a flexible substrate made of flexible material; (3) The material of the substrate is an inorganic material or an organic material; further, the inorganic material is at least one of the following: metal or its alloy, metal oxide or silicon-containing inorganic non-metallic material; the organic material is a synthetic material or a natural material, and even further, the synthetic material is at least one of the following: plastic, rubber and fiber, and the natural material is at least one of the following: wood and leaves; preferably, the substrate is a PDMS substrate; (4) The dry film is a photosensitive film. In the step of preparing the dry film pattern, the dry film pattern is prepared by selectively irradiating the photosensitive dry film. Preferably, the dry film pattern is obtained by developing. The developing step is: developing the irradiated dry film in a developing agent to obtain the dry film pattern. (5) In the step of preparing liquid metal pattern, the liquid metal is attached to the substrate surface by scraping.

8. The method for preparing liquid metal patterns as described in claim 7, characterized in that, Meets at least one of the following conditions: (1) The PDMS substrate is prepared by the following method: mixing PDMS prepolymer and curing agent evenly, curing, and cutting to a predetermined size; preferably, the PDMS substrate is prepared by the following method: mixing PDMS prepolymer and curing agent Sylgard184 evenly at a mass ratio of 8-12:1, first refrigerating at 3-7°C to remove air bubbles, then curing at 60-100°C, and cutting to a predetermined size; more preferably, the PDMS substrate is prepared by the following method: mixing PDMS prepolymer and curing agent Sylgard184 evenly at a mass ratio of 10:1, first refrigerating at 5°C to remove air bubbles, and then curing at 80°C; (2) In the substrate surface activation step, the substrate is first placed in anhydrous ethanol and deionized water for ultrasonic cleaning, and then placed in a cleaning agent for treatment. (3) In the substrate surface activation step, the glass aqueous solution is a mixed solution of deionized water and glass water in a volume ratio of 7-11:1, preferably 9:1; (4) In the substrate surface activation step, the plasma treatment is performed using a plasma surface treatment machine; (5) In the step of preparing the dry film pattern, the selective irradiation conditions are: wavelength of 400-410nm, for example 405nm, exposure time of 3-10min, for example 5min, and power of 5-15w, for example 10w; (6) In the developing step, the developing agent is an aqueous solution of Na2CO3, preferably a 0.5-3% aqueous solution of Na2CO3, for example a 1.0% aqueous solution of Na2CO3, and / or the developing time is 60-120s, preferably 90s; (7) In the step of preparing the liquid metal pattern, the coating thickness of the liquid metal is 0.01-0.5 mm, preferably 0.1-0.3 mm, and more preferably 0.2 mm.

9. A flexible sensor, characterized in that, The invention includes a flexible substrate and a liquid metal pattern attached to the flexible substrate, wherein the liquid metal pattern is prepared from the modified liquid metal according to claim 1 or 2; Preferably, the flexible substrate is a flexible substrate made of PDMS, glass, or hydrogel, for example, a PDMS flexible substrate; and / or, the thickness of the liquid metal pattern is 0.01-0.5 mm, more preferably 0.1-0.3 mm, for example, 0.2 mm.

10. The method for fabricating the flexible sensor according to claim 9, characterized in that, Includes the following steps: The result is obtained by encapsulating a flexible substrate with a liquid metal pattern. Preferably, the encapsulation step involves coating the surface of the flexible substrate with a substrate material prepolymer and curing it to prepare an encapsulation layer. More preferably, the thickness of the encapsulation layer is 0.01-0.5 mm, further 0.1-0.3 mm, for example 0.2 mm.

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