Method for preparing stretchable wire of laser in-situ activated liquid metal composite material

Abstract

The present application relates to the technical field of flexible materials, and particularly relates to a preparation method of stretchable conductive wire based on laser in-situ activation of liquid metal composite material. The method first carries out ultrasonic treatment on the liquid metal to obtain liquid metal particles, then fully mixes the liquid metal particles with a solution of elastic polymer SEBS to prepare ink, further prepares a stretchable conductive wire pattern by means of the ink and in combination with laser cutting and laser in-situ activation technology, and finally transfers and encapsulates to realize preparation of the stretchable conductive wire. The method uses two self-healing materials, i.e. liquid metal and SEBS, to form a composite material, and proposes a technology of laser scanning in-situ activation of liquid metal composite material, which not only overcomes the shortcomings of the prior art, but also meets the demand of flexible electronic devices for stretchable conductive wire.

Description

Technical Field

[0001] The present invention relates to the technical field of flexible materials, and in particular to a method for preparing a stretchable conductor of a laser in-situ activated liquid metal composite material. Background Art

[0002] Flexible electronics hold great promise for applications in areas such as personalized medicine. Currently, most flexible electronic devices rely on wires to transmit signals. However, traditional wires, made of solid metal, are only bendable and lack stretchability, limiting their application within the human body. Therefore, achieving stretchability in flexible electronic wires remains a major challenge in this field.

[0003] Liquid metal (LM, here refers to gallium-indium liquid alloy) is liquid at room temperature. It combines the deformable and reconfigurable fluid properties of liquids with the high electrical and thermal conductivity of metals. Its good plasticity and electrical conductivity make it suitable for the preparation of flexible electronic devices. Gallium-based liquid metal has certain biocompatibility and is suitable as a material for wearable flexible circuits and flexible wires. However, due to the presence of a surface oxide layer, liquid metal has high surface tension, making it difficult to pattern using traditional printing or printing methods. It is usually injected into microfluidic channels or ultrasonically dispersed into particles and then assembled on a flexible substrate to achieve patterning. However, these methods are complicated and costly to operate. Due to differences in individual operating levels, the wire patterning effect will be unstable. In addition, the liquid metal particles assembled on the flexible substrate are usually not conductive and require laser selective sintering activation. There are problems such as the activated liquid metal being easily overflowed and broken by external forces, and residual liquid metal particles affecting the wire performance. Therefore, it is urgently needed to be solved.

[0004] The above content is only used to assist in understanding the technical solution of the present invention and does not mean that the above content is the closest prior art. Summary of the Invention

[0005] The technical problem to be solved by the present invention is to provide a method for preparing stretchable wires of laser in-situ activated liquid metal composite materials. The method utilizes liquid metal and SEBS, two self-healing materials, to form a composite material, and proposes a technology for in-situ activation of the liquid metal composite material by laser scanning. This method not only overcomes the shortcomings of the existing technology, but also meets the needs of flexible electronic devices for stretchable wires.

[0006] To achieve the above-mentioned purpose, the technical solution of the present invention is implemented as follows: a method for preparing a stretchable conductor made of laser in-situ activated liquid metal composite material; the preparation method comprises the following steps:

[0007] S1. Preparation of liquid metal:

[0008] The molten gallium and indium are mixed according to the mass ratio and heated in an oil bath to obtain liquid metal LM.

[0009] Compared with gallium, which has a melting point of 29.76°C, gallium-indium liquid alloy has a lower melting point (15.5°C) and can be liquid at room temperature.

[0010] S2. Preparation of liquid metal particles:

[0011] S21, placing liquid metal (LM) into a surfactant solution diluted with anhydrous ethanol, and performing water bath sonication to obtain a LM particle suspension;

[0012] S22, after standing, taking out the upper layer of LM particle suspension, centrifuging and pouring out the liquid, adding anhydrous ethanol to wash away excess surfactant, and centrifuging and washing several times to obtain solid LM particles;

[0013] S3. Preparation of SEBS solution:

[0014] SEBS and an organic solvent are mixed according to a mass ratio and then ultrasonicated in a water bath until SEBS is completely dissolved to obtain a SEBS solution;

[0015] Preparation of S4 and LM ink:

[0016] LM particles and SEBS solution were mixed in proportion, shaken, and then magnetically stirred to obtain LM ink;

[0017] Magnetic stirring not only saves manpower but also ensures that the LM particles and SEBS solution are fully mixed.

[0018] S5. Patterning of LM ink:

[0019] S51. Apply LM ink on a polytetrafluoroethylene substrate, and transfer the ink and substrate to a glass slide after the solvent has evaporated completely.

[0020] Doctor coating can ensure uniform and adjustable film thickness. After the organic solvent is completely volatilized, the LM ink becomes a solid film. Compared with assembling LM particles on the elastomer polymer, the LM particles only exist on the surface of the elastomer. The LM particles in the ink are evenly distributed in the SEBS elastomer. After activation, SEBS can encapsulate the LM, improve the stretchability and prevent LM leakage.

[0021] S52. Cutting a conductor pattern on the LM ink by laser.

[0022] Compared to patterning liquid metal using photolithographic microfluidic channels, laser cutting of liquid metal inks is simple, low-cost, and requires a short patterning process. Compared to patterning using liquid metal inks printed on flexible printers, which can be prone to needle clogging and greatly impact the patterning effect, laser cutting of liquid metal inks offers high precision and stable results. Laser cutting removes excess ink after patterning, preventing excess liquid metal from affecting the electrical or radio frequency performance of the pattern.

[0023] S6. In-situ activation of LM ink:

[0024] By in-situ activating the ink through laser scanning, the conductor pattern is transformed from non-conductive to conductive.

[0025] Laser scanning evaporates the oxide layer on the surface of the LM particles, activating them in situ and converging them into a conductive network. Compared to mechanical activation, laser scanning activation allows for precise control of power and area, enabling complete pattern coverage. Activated conductivity is high and stable, regardless of operator skill.

[0026] S7. Transfer and packaging of wires:

[0027] The wire pattern was transferred onto a SEBS substrate film and encapsulated with a layer of SEBS film to obtain a stretchable wire based on liquid metal ink.

[0028] Compared with PDMS, the most commonly used elastomeric polymer in flexible electronic devices, SEBS has better stretchability (elongation at break can reach 1000%) and good self-healing properties. The self-healing properties of SEBS are used to achieve encapsulation, and the bond between the encapsulation and the substrate is strong, which effectively protects the wire pattern and improves its durability.

[0029] Preferably, in step S1, the mass ratio of gallium to indium is 75.5:24.5; the oil bath heating time is 3 hours; the oil bath heating conditions are as follows: oil bath heating is performed on a hot plate at 85°C, magnetic stirring is turned on while heating, the speed is 600-800 r / min, and nitrogen needs to be continuously introduced during heating.

[0030] Preferably, in step S21, the liquid metal is a gallium-indium alloy, and the added volume of the liquid metal is 0.5 mL; the surfactant is ethyl 3-mercaptopropionate, the added volume of the surfactant solution is 15 mL, and the concentration of the surfactant solution is 0.1 mM / L, and the water bath ultrasound time is 30 min (water bath ultrasound power 30%, working 3 s, rest 2 s).

[0031] Preferably, in step S22, the solution of the LM particle suspension is 30 mL; the amount of anhydrous ethanol added for washing is 25-30 mL; the centrifugal speed of the centrifugal washing is 5000 r / min, the centrifugal time of the centrifugal washing is 15 min, and the number of centrifugal washing times is 2-3 times; the particle size of the prepared LM particles is 0.8-1.2 μm.

[0032] Preferably, in step S3, the organic solvent is a mixed solution of toluene and n-hexane; the mass ratio of SEBS particles to organic solvent in the SEBS solution is SEBS:n-hexane:toluene=1:1:4; and the water bath ultrasonic mixing time is 3-6 h.

[0033] Preferably, in step S4, the mass ratio of the LM particles to the SEBS solution is 7:1-8:1; the oscillation time is 1-3 min, the magnetic stirring time is 30-60 min, and the magnetic stirring speed is 600 r / min.

[0034] Preferably, in step S51, the coating is performed using an adjustable scraper coater with a scraper height of 500 μm; the volume of the LM ink is 3-5 mL; the glass sheet is 14 cm long, 7 cm wide, and 2 mm thick; and the solvent takes more than 12 hours to completely evaporate.

[0035] Preferably, in step S52, the laser is an ultraviolet laser; the cutting parameters are a rate of 500-1000 mm / s, a power of 50-70%, a frequency of 40-60 kHz, and a number of laser cutting circles of 10.

[0036] Preferably, in step S6, the laser scanning range should completely include the conductor pattern, and the parameters of the laser in-situ activation are a rate of 500-1000 mm / s, a power of 40-60%, a frequency of 40-60 kHz, and a laser scanning circle of 1.

[0037] Preferably, in step S7, the SEBS base film is prepared by spin coating of a SEBS solution, the components of the SEBS solution are SEBS: n-hexane: toluene = 1:1:2 by weight, and the spin coating speed during the spin coating preparation is 300-500 r / min, and the transfer is performed in a semi-cured state after 10-15 minutes; the SEBS film for encapsulation is obtained by spin coating a SEBS solution with a composition of SEBS: n-hexane: toluene = 1:1:3 or 1:1:2 on a silicon wafer and then volatilizing it, and the volatilization time is more than 12 hours.

[0038] The beneficial effects of the present invention are embodied in:

[0039] (1) The method provided by the present invention prepares a stretchable conductor by mixing liquid metal particles and a SEBS solution to prepare an ink, and then scraping, laser cutting, and laser activating the ink. The operation process is relatively simple. Scraping allows for uniform ink coating, and laser cutting allows for precise patterning. This improves preparation accuracy and ensures good patterning results, avoiding the unstable patterning results caused by differences in operating levels in photolithographic microfluidic channels and flexible electronic printing.

[0040] (2) The method provided by the present invention uses laser in-situ activation of liquid metal ink, which is simple to operate and greatly ensures the success rate of activation. The SEBS in the ink also acts as an encapsulator for the liquid metal after in-situ activation, protecting the integrity of the pattern. Compared with laser selective activation of the liquid metal conductive layer, the present invention effectively avoids the problem that the activated liquid metal is easily overflowed by external forces, thereby destroying the pattern, and the problem that the liquid metal particles left after activation have a negative impact on the electrical properties.

[0041] (3) The method provided by the present invention utilizes the synergistic effect of liquid metal and SEBS dual self-healing materials to enable the activated conductor pattern to exhibit good stretchability and conductivity. The resistance remains stable under strains up to 100%, and it can well adapt to different deformation requirements. In addition, the excellent self-healing ability of SEBS makes the pattern easy to transfer and encapsulate, and has excellent durability after encapsulation.

[0042] (4) The method provided by the present invention can also be applied to the preparation of flexible radio frequency devices and has great application potential in the field of flexible electronics. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] Figure 1 It is a schematic flow chart of the patterning method and activation method of the liquid metal ink of the present invention;

[0044] Figure 2 is a scanning electron microscope image of the liquid metal ink before activation in the present invention;

[0045] Figure 3 is a scanning electron microscope image of the liquid metal ink after laser scanning activation in the present invention;

[0046] Figure 4 is the square resistance diagram of the liquid metal ink after being activated by laser scanning at different powers in the present invention;

[0047] Figure 5 This is a graph showing the change in resistance of the activated liquid metal ink with continuous 100% stretching in the present invention;

[0048] Figure 6 This is a graph showing changes in S11 of the coil prepared with liquid metal ink in the present invention under different degrees of stretching. DETAILED DESCRIPTION

[0049] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of the embodiments. In the absence of conflict, the embodiments in this application and the features in the embodiments can be combined with each other. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0050] like Figure 1-6 As shown:

[0051] The present invention provides a method for preparing stretchable conductors using laser in-situ activated liquid metal composite materials. The principle of the method provided by the present invention is as follows: first, liquid metal is ultrasonically treated to obtain liquid metal particles, which are then thoroughly mixed with a solution of the elastic polymer SEBS to prepare an ink. The ink is then used in combination with laser cutting and laser in-situ activation techniques to prepare a stretchable conductor pattern. Finally, the stretchable conductor is transferred and packaged to achieve the preparation of the stretchable conductor. The mass ratio between the liquid metal particles and the SEBS solution is one or more of 7:6, 5:4, and 4:3. The mixing method of the liquid metal particles and the SEBS solution is selected from one or more of water bath sonication, oscillation, and magnetic stirring. The laser frequency is selected from one or more of 40 kHz, 50 kHz, and 60 kHz. The laser scanning activation power is selected from one or more of 40%, 50%, and 60%.

[0052] Example 1

[0053] In this example, the aforementioned method was used to heat 100 g of gallium and 32.5 g of indium in an 85°C oil bath with nitrogen continuously introduced for 3 hours to produce liquid gallium-indium metal. 0.5 mL of LM was added to 15 mL of a 0.1 mM / L ethanol solution of ethyl 3-mercaptopropionate, and ultrasonication at 30% power for 30 minutes produced a LM particle suspension.

[0054] Centrifuge 30 mL of the LM particle suspension at 5000 r / s for 15 minutes to obtain a LM particle precipitate. Mix the LM particle precipitate with 30 mL of anhydrous ethanol by vortexing and let it stand for 5 minutes. Wash the supernatant by centrifugation three times to obtain LM particles.

[0055] 5 g of SEBS particles, 5 g of n-hexane and 20 g of toluene solution were mixed and ultrasonicated in a water bath for 6 h until the SEBS particles were completely dissolved to obtain a SEBS solution.

[0056] 3.5 g of LM particles were mixed with 3 g of SEBS solution, shaken for 3 minutes, and then magnetically stirred for more than 30 minutes to obtain LM ink; the LM ink was scraped onto a polytetrafluoroethylene substrate using a scraper coater to a thickness of 500 μm and placed in a fume hood for more than 12 hours to allow the organic solvent to evaporate.

[0057] The evaporated ink was transferred to a glass slide along with a polytetrafluoroethylene substrate. Ten circles of the evaporated LM ink were cut using an ultraviolet laser at a speed of 500 mm / s, a power of 60%, and a frequency of 50 kHz. The excess part was torn off with tweezers to obtain a conductor pattern.

[0058] A UV laser scans a single conductor pattern at a speed of 500 mm / s, 40% power, and a frequency of 50 kHz. The liquid metal particles in the ink are activated in situ, transforming the pattern from non-conductive to conductive.

[0059] Spin coat the SEBS solution on the silicon wafer at a speed of 500 r / min, place the silicon wafer in a fume hood and wait for 10 minutes, the toluene in the SEBS solution will partially evaporate, and the SEBS base film will be semi-cured. Paste the conductor pattern together with the polytetrafluoroethylene base with the pattern facing down on the semi-cured SEBS base film, place it in a fume hood and wait for 12 hours until the SEBS base is completely cured, tear off the polytetrafluoroethylene, and the transfer is complete.

[0060] The SEBS solution was spin-coated at a speed of 500 r / min, and the film was obtained after being placed in a fume hood and waiting for 12 hours. The SEBS film was cut to the appropriate size before pasting it on the transferred wire pattern. After packaging, a stretchable wire based on liquid metal ink was obtained.

[0061] Example 2

[0062] In this example, the above method was used to heat 100 g of gallium and 32.5 g of indium in an 85°C oil bath with nitrogen continuously introduced for 3 hours to produce gallium-indium liquid metal. 0.5 mL of LM was added to 15 mL of a 0.1 mM / L ethanol solution of ethyl 3-mercaptopropionate. Ultrasonication at 30% power was then performed for 30 minutes to obtain a LM particle suspension.

[0063] Centrifuge 30 mL of the LM particle suspension at 5000 r / s for 15 minutes to obtain a LM particle precipitate. Mix the LM particle precipitate with 30 mL of anhydrous ethanol by vortexing and let it stand for 5 minutes. Wash the supernatant by centrifugation three times to obtain LM particles.

[0064] 5 g of SEBS particles, 5 g of n-hexane and 20 g of toluene solution were mixed and ultrasonicated in a water bath for 6 h until the SEBS particles were completely dissolved to obtain a SEBS solution.

[0065] 4 g of LM particles were mixed with 3 g of SEBS solution, and the mixture was shaken for 10 minutes and then ultrasonicated in a water bath for more than 30 minutes to obtain LM ink. The LM ink was scraped onto a polytetrafluoroethylene substrate using a scraper coater with a thickness of 500 μm. The ink was placed in a fume hood for more than 12 hours to allow the organic solvent to evaporate.

[0066] The evaporated ink was transferred to a glass slide along with a polytetrafluoroethylene substrate. Ten circles of the evaporated LM ink were cut using an ultraviolet laser at a speed of 500 mm / s, a power of 60%, and a frequency of 50 kHz. The excess part was torn off with tweezers to obtain a conductor pattern.

[0067] SEBS substrate film was prepared by spin coating SEBS solution on silicon wafer at a speed of 500 r / min. The silicon wafer was placed in a fume hood and waited for 10 min. The toluene in the SEBS solution partially evaporated and the SEBS substrate film was semi-cured. The conductor pattern together with the polytetrafluoroethylene substrate was pasted on the semi-cured SEBS substrate film with the pattern facing down. After the SEBS substrate was completely cured in a fume hood and waited for 12 h, the polytetrafluoroethylene was removed and the transfer was completed.

[0068] A UV laser was used to scan a circle of the conductor pattern at a speed of 500 mm / s, 60% power and a frequency of 60 kHz. The liquid metal particles in the ink were activated in situ, and the pattern changed from non-conductive to conductive.

[0069] The transferred wire pattern was spin-coated with SEBS solution at a speed of 500 r / min. The wire was placed in a fume hood and waited for 12 hours for the toluene to completely evaporate. The packaging was completed, and a stretchable wire based on liquid metal ink was obtained.

[0070] It should be noted that the two packaging methods are differentiated according to the different practical applications of the present invention; if the present invention is applied to the preparation of flexible wires, since the wires need to leave interfaces for the connection of electronic components, the packaging method of Example 1 is adopted, and the SEBS film is pasted for packaging through the self-healing properties of the SEBS substrate. The SEBS film used for packaging can be cut to a suitable size by laser cutting before pasting and an interface is left for the subsequent connection of electronic components; if the present invention is applied to the preparation of flexible passive RF devices, the packaging method of Example 2 is adopted, and the SEBS solution is spin-coated on the pattern for packaging, and the packaging is completed after the organic solvent in the solution is completely volatilized. The packaging method of Example 2 can achieve complete packaging and can better protect the device.

[0071] like Figure 1Compared with the method of patterning liquid metal by photolithographic microfluidic channels or ultrasonic dispersion into particles and then assembling them on a flexible substrate, the present invention has a simple operation process, low cost and less time consumption, and the entire process can be completed within 24 hours. In addition, compared with the method of patterning liquid metal ink by flexible electronic printing, the present invention is less affected by personal operation level and has a stable pattern forming effect. After patterning by laser cutting, the present invention activates the liquid metal in the ink in situ by laser scanning. Since excess ink is removed after patterning by laser cutting, there is no problem of residual liquid metal particles affecting the performance of the conductor that exists in the laser selective sintering activation of liquid metal particles assembled on the flexible substrate.

[0072] like Figure 2 As shown, before activation, the liquid metal particles are discretely embedded in the SEBS elastomer, and there is an oxide layer on the surface of the liquid metal particles, and the ink is not conductive.

[0073] like Figure 3 As shown, after activation, the surface oxide layer of the liquid metal particles is evaporated and reassembled together to form a continuous liquid metal conductive network in situ in the SEBS elastomer, and the ink is conductive; under the synergistic effect of the two self-healing materials, SEBS and liquid metal, the activated ink has good conductivity and good stretchability, and can be used as a stretchable wire in flexible electronic devices; compared with the method of laser selective sintering to activate liquid metal particles assembled on a flexible substrate, the SEBS with good stretchability and self-healing properties in the present invention wraps the liquid metal after in situ activation therein, which plays a role of encapsulation, ensuring that the liquid metal will not overflow due to external force and destroy the pattern under continuous stretching.

[0074] like Figure 4 As shown in the figure, after laser activation, the ink changes from non-conductive to conductive. When the activation power is 40%, the sheet resistance of the ink decreases significantly. The sheet resistance measured by the four-probe sheet resistance meter reaches mΩ / □ After conversion, the conductivity can reach 10 6 S / m, compared to the conductivity of the ink after mechanical activation 10 4 The S / m ratio is significantly improved, and it can be used as a conductor in flexible electronic devices. When the power is 70%, most of the liquid metal evaporates, the pattern is destroyed and it is not conductive.

[0075] like Figure 5 As shown, compared with traditional metal wire materials commonly used in current flexible electronic devices that can only bend but not stretch, the liquid metal ink in the present invention has a resistance change rate of less than 10% during multiple consecutive 100% stretching and has good recovery properties, which is more in line with the needs of flexible electronic devices.

[0076] like Figure 6As shown, compared with most flexible antennas / coils currently prepared by combining thin solid metal materials or conductive nanomaterials on flexible substrates, which can only bend but do not have good stretchability, the flexible coil prepared by the method of the present invention still maintains a stable frequency under 100% stretching and the S11 value at the frequency is below -10 dB, which proves that the coil still has good signal transmission capability under high stretching conditions. Therefore, the present invention can be used to prepare flexible radio frequency devices.

[0077] From the above method and the preparation process of Example 1 and Implementation 2 using the method, it can be seen that the method provided by the present invention synergistically utilizes the properties of two self-healing materials, liquid metal and SEBS. Liquid metal is liquid at room temperature and has fluid-like deformability and reconfigurability, while having the high conductivity of metal. SEBS, as an elastic polymer, has good stretchability and self-healing ability, providing a good flexible foundation for composite materials. The synergistic effect of the two enables the prepared wires to have good conductivity and stretchability. At the same time, the structure and electrical properties can be kept relatively stable during the stretching process. In addition, through the key step of in-situ activation of the ink by laser scanning, the surface oxide layer of the liquid metal particles in SEBS can be accurately evaporated and sintered together, prompting the wire pattern to change from a non-conductive state to a conductive state. SEBS plays a packaging role after the liquid metal particles are activated in situ, preventing the liquid metal from overflowing and protecting the integrity of the pattern, thereby achieving high-quality preparation of stretchable wires.

[0078] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A method for preparing a stretchable conductor using laser in-situ activated liquid metal composite material, characterized in that: The preparation method comprises the following steps: S1. Preparation of liquid metal: The molten gallium and indium are mixed according to the mass ratio and heated in an oil bath to obtain liquid metal LM; S2. Preparation of liquid metal particles: S21, placing the liquid metal LM into a surfactant solution diluted with anhydrous ethanol, and performing water bath sonication to obtain a LM particle suspension; S22, after standing, taking out the upper layer of LM particle suspension, centrifuging and pouring out the liquid, adding anhydrous ethanol to wash away excess surfactant, and centrifuging and washing several times to obtain solid LM particles; S3. Preparation of SEBS solution: SEBS and an organic solvent are mixed according to a mass ratio and then ultrasonicated in a water bath until SEBS is completely dissolved to obtain a SEBS solution; Preparation of S4 and LM ink: LM particles and SEBS solution were mixed in proportion, shaken, and then magnetically stirred to obtain LM ink; S5. Patterning of LM ink: S51, apply LM ink on the polytetrafluoroethylene substrate, and transfer the ink and substrate to a glass slide after the solvent evaporates completely; S52, cutting a conductor pattern on the LM ink by laser; S6. In-situ activation of LM ink: By in-situ activating the ink through laser scanning, the conductor pattern is transformed from non-conductive to conductive; S7. Transfer and packaging of wires: The wire pattern was transferred onto a SEBS substrate film and encapsulated with a layer of SEBS film to obtain a stretchable wire based on liquid metal ink.

2. The method for preparing a stretchable conductor of a laser in-situ activated liquid metal composite material according to claim 1, characterized in that: In step S1, the mass ratio of gallium to indium is 75.5:24.5; and the oil bath heating time is 3 hours.

3. The method for preparing a stretchable conductor of a laser in-situ activated liquid metal composite material according to claim 1, characterized in that: In step S21, the liquid metal is a gallium-indium alloy, and the added volume of the liquid metal is 0.5 mL; the surfactant is ethyl 3-mercaptopropionate, the added volume of the surfactant solution is 15 mL, and the concentration of the surfactant solution is 0.1 mM / L; the water bath ultrasonication time is 30 min.

4. The method for preparing a stretchable conductor of laser in-situ activated liquid metal composite material according to claim 3, characterized in that: In step S22, the solution of the LM particle suspension is 30 mL; the amount of anhydrous ethanol added for washing is 25-30 mL; the centrifugal speed of the centrifugal washing is 5000 r / min, the centrifugal time of the centrifugal washing is 15 min, and the number of centrifugal washings is 2-3 times; the particle size of the prepared LM particles is 0.8-1.2 μm.

5. The method for preparing a stretchable conductor of laser in-situ activated liquid metal composite material according to claim 1, characterized in that: In step S3, the organic solvent is a mixed solution of toluene and n-hexane; the mass ratio of SEBS particles to organic solvent in the SEBS solution is SEBS:n-hexane:toluene=1:1:4; and the water bath ultrasonic mixing time is 3-6 h.

6. The method for preparing a stretchable conductor of a laser in-situ activated liquid metal composite material according to claim 1, characterized in that: In step S4, the mass ratio of the LM particles to the SEBS solution is 7:1-8:1; the oscillation time is 1-3 min, the magnetic stirring time is 30-60 min, and the magnetic stirring speed is 600 r / min.

7. The method for preparing a stretchable conductor of a laser in-situ activated liquid metal composite material according to claim 1, characterized in that: In step S51, the coating is performed using an adjustable scraper coater with a scraper height of 500 μm; the volume of the LM ink is 3-5 mL; the glass sheet is 14 cm long, 7 cm wide, and 2 mm thick; and the solvent takes more than 12 hours to completely evaporate.

8. The method for preparing a stretchable conductor of laser in-situ activated liquid metal composite material according to claim 7, characterized in that: In step S52, the laser is an ultraviolet laser; the cutting parameters are a rate of 500-1000 mm / s, a power of 50%-70%, a frequency of 40-60 kHz, and a number of laser cutting circles of 10.

9. The method for preparing a stretchable conductor of laser in-situ activated liquid metal composite material according to claim 1, characterized in that: In step S6, the laser scanning range should completely include the conductor pattern, and the parameters of the laser in-situ activation are a rate of 500-1000 mm / s, a power of 40-60%, a frequency of 40-60 kHz, and a laser scanning circle of 1.

10. The method for preparing a stretchable conductor of laser in-situ activated liquid metal composite material according to claim 1, characterized in that: In step S7, the SEBS base film is prepared by spin coating a SEBS solution, the components of the SEBS solution are SEBS: n-hexane: toluene = 1:1:2 by weight, and the spin coating speed during the spin coating preparation is 100-500 r / min, and the transfer is performed in a semi-cured state after 10-15 minutes; the SEBS film for packaging is obtained by spin coating a SEBS solution with a composition of SEBS: n-hexane: toluene = 1:1:3 or 1:1:2 on a silicon wafer and then volatilizing it, and the volatilization time is more than 12 hours.

Images