Apparatus and method for electrohydrodynamic jetting of liquid metal microwire strain sensors

Abstract

The application discloses an electrohydrodynamic jet preparation device and method of a liquid metal microwire strain sensor. By building a device suitable for carrying out an electrohydrodynamic jet process, the formation of the liquid metal microwire can avoid the support of expensive equipment, the implementation of complicated steps and the selection of specific materials. By providing an electrostatic elimination module, the negative effects of the discontinuity of the jet structure and the uneven manufacturing caused by the deposition of the substrate charge in the continuous electrohydrodynamic jet process are solved.

Description

TECHNICAL FIELD

[0001] The application belongs to the field of advanced manufacturing technology, and relates to a device and a method for electrohydrodynamic jet printing of liquid metal microwire strain sensor. BACKGROUND

[0002] Liquid metal is a kind of metal or metal alloy that presents liquid state at room temperature or near room temperature, usually composed of low melting point metals such as gallium, indium and tin, and can maintain liquid state at room temperature. Liquid metal has similar high conductivity and excellent processability as solid metal, and exhibits flexible deformation ability, so it has attracted attention in many frontier fields such as flexible electronics. However, due to the material characteristics of large surface tension and low viscosity, liquid metal has the disadvantages of difficulty in forming and difficulty in high-precision patterning. Existing liquid metal forming techniques often involve cumbersome steps, expensive equipment and specific substrate material requirements, which limit the popularization and application of liquid metal materials, and new forming methods need to be developed.

[0003] Flexible strain sensor is a research hotspot in the field of sensors in recent years. Compared with traditional rigid strain sensors, flexible strain sensors can better work on irregular and dynamically changing surfaces, and are usually light, thin, portable and easy to integrate. With the development of human society, the demand for intelligent wearable devices, soft robots, self-powered technology and other technologies is constantly driving the research of flexible strain sensors. The characteristics of liquid metal are very suitable for manufacturing flexible strain sensors, and it has great potential in specific applications such as stretchable electrodes.

[0004] Electrohydrodynamic jet printing applies thousands of volts to the jet needle, thereby establishing a strong electric field between the jet needle and the substrate. Under the action of the strong electric field, the surface of the jet printing ink is subjected to a large electric field force, which can help the solution overcome the surface tension, flow out of the nozzle outlet and form a Taylor cone, and finally form a stable jet. The size of the stable electrohydrodynamic jet can be as small as nanoscale, and by controlling the movement of the substrate, the jet liquid can be received to build functional structures on the substrate. By adjusting the process parameters, microstructures of different sizes can be manufactured and excellent resolution control ability can be achieved. In recent years, electrohydrodynamic jet printing technology has attracted widespread attention in the field of nanomaterials and flexible electronic device preparation due to its strong ink compatibility and high processing resolution. These advantages of electrohydrodynamic jet printing can break through the bottleneck of efficient and high-resolution patterning of liquid metal functional structures, effectively change the limitations in existing liquid metal microwire structure forming technology, and provide a feasible process path for the application and popularization of liquid metal. SUMMARY

[0005] The purpose of this invention is to solve some of the problems of cumbersome molding steps, expensive equipment, and high requirements for substrate materials in existing liquid metal materials. It develops a method for electrohydraulic inkjet printing of liquid metal micron-line strain sensors, invents an apparatus suitable for this manufacturing method, and solves the negative impact caused by substrate charge deposition during electrohydraulic inkjet printing of liquid metal microstructures.

[0006] Some embodiments of the present invention provide an electrofluid printing fabrication apparatus for a liquid metal microwire strain sensor. The liquid metal microwire strain sensor includes liquid metal microwires printed on a first flexible film, terminals connected to the liquid metal microwires, and a second flexible film heat-pressed onto the first flexible film, the liquid metal microwires, and the terminals. The electrofluid printing fabrication apparatus includes an electric field control module, a paste supply module, a printing motion module, a visual observation module, and an electrostatic elimination module. The paste supply module supplies the raw materials for electrofluid printing. The printing motion module includes a three-axis motion platform, a printing substrate, and a printhead. The printing substrate is fixed on the Y-axis, and the printhead is mounted on the crossbeam of the three-axis motion platform and connected to a high-voltage DC power supply via wires. The electric field control module applies an electric field to the electrofluid printing substrate. On the printing motion module; the visual observation module observes the jet state of the electrohydraulic printing and provides the observed jet state to the electric field control module and the slurry supply module; the electrostatic elimination module includes an ion air bar, a high-voltage ion power supply, and a fixed support assembly; the ion air bar is fixed to the crossbeam of the three-axis motion platform through the fixed support assembly, so that it is positioned further forward than the nozzle in the printing direction of the liquid metal microwire; the ion air bar is configured to ionize the air to generate a large number of positive and negative charges when the electrohydraulic printing of the liquid metal microwire structure begins and eject them from the ion emission needle; so that when the printing substrate passes under the ion air bar with the three-axis motion platform, the ionized ions will collide with the first flexible film on the printing substrate and cancel out the charges generated on the first flexible film by the high-voltage electric field excited by the electric field control module during the continuous electrohydraulic printing process.

[0007] In some embodiments, the electric field control module includes a high-voltage DC power supply; the output voltage is changed by adjusting the knob on it, and the electric field is applied to the electro-hydraulic inkjet printing motion module by connecting it to the nozzle through a wire; the slurry supply module includes a precision injection pump, a fixing rod assembly, a push plate, and a syringe container; wherein the fixing rod assembly is fixed to the precision injection pump, the push plate has a through hole that mates with the fixing rod assembly and is mounted thereon, one end of the syringe container is fixed to the fixing rod assembly, and the other end is in contact with the push plate. When the precision injection pump starts working, the push plate is subjected to pressure and pushes the syringe container to move, thereby pushing out the liquid metal slurry in the syringe container.

[0008] In some embodiments, the high-voltage DC power supply and the syringe container are connected to the printhead via pipelines and electrical circuits, respectively. The voltage and flow rate of the electrofluid printing process are controlled by controlling the output voltage of the high-voltage DC power supply and the mass flow rate of the precision injection pump.

[0009] In some embodiments, the three-axis motion platform of the printing motion module provides three-dimensional motion in three-dimensional space, wherein the motion in the X and Y directions is used to change the spatial position of the printing substrate, and the motion in the Z direction is used to change the spatial position of the printhead. The combination of the two allows the printing substrate and the printhead to reach any relative position in three-dimensional space.

[0010] In some embodiments, the electrostatic elimination module is installed above the movement path of the printing substrate and does not interfere with the printhead.

[0011] The embodiments of the present invention propose a liquid metal micron-wire strain sensor electrohydrodynamic inkjet printing method based on any one of the above-described devices, which includes the following steps: Step S1, selecting and preparing a liquid metal paste suitable for electrohydrodynamic inkjet printing, selecting and preparing a pair of TPU films as the first flexible film and the second flexible film, and preparing a pair of terminals;

[0012] Step S2: Place and fix the first TPU film on the printing substrate as the printing base; adjust the nozzle position up and down to a suitable printing height; Step S3: Draw the prepared liquid metal slurry into the syringe container, install the syringe container on the fixing rod assembly, move the push plate to contact the syringe container and make the needle slightly dispense liquid; Step S4: Adjust the observation camera of the visual observation module so that its focus is near the nozzle to clearly image and observe the electrofluid jet pattern of the liquid metal slurry; Step S5: Turn on the precision injection pump and high-voltage DC power supply, adjust the flow rate and voltage until a stable cone jet pattern of liquid metal slurry is observed in the observation camera; according to the main structure design of the manufactured liquid metal micron strain sensor, fine-tune the output flow rate of the precision injection pump and the output of the high-voltage DC power supply. The voltage and the height of the nozzle from the printing substrate are adjusted to stabilize the jet diameter at a predetermined size; Step S6: Turn on the high-voltage ion power supply, turn on the ion air bar, and confirm that the ion air bar is working properly; Step S7: Control the three-axis motion platform to make the first TPU film substrate on the printing substrate completely pass over the nozzle along the X or Y direction, and the current fluid jet of the liquid metal paste prints a stable micron-line structure on the first TPU film; Step S8: Place wiring terminals at both ends of the liquid metal micron-lines printed on the first TPU film substrate, and lead out wires from the wiring terminals; Step S9: Take a second TPU film and cover it on the first TPU film substrate that has been printed with liquid metal micron-lines, and use a hot pressing process to bond the two films together to complete the encapsulation of the liquid metal micron-line strain sensor.

[0013] In some embodiments, the liquid metal slurry is a blend of liquid metal and polymer solvent; wherein a eutectic gallium indium alloy (EGaIn) is used as the liquid metal, and the weight percentage of Ga:In is 3~4:1.

[0014] The beneficial effects of this invention include: This invention provides an apparatus and method for electrohydraulic inkjet printing of liquid metal microwire strain sensors. By constructing an apparatus suitable for electrohydraulic inkjet printing, the molding of liquid metal microwires can avoid the need for expensive equipment, cumbersome steps, and specific material selection. The characteristics of electrohydraulic inkjet printing technology allow for quantitative control of the shape and molding resolution of the liquid metal microwires, enabling the on-demand manufacturing of liquid metal microwire structures according to the intended use of the strain sensor. It solves the negative impacts of substrate charge deposition on the manufacturing process during continuous electrohydraulic inkjet printing, such as discontinuous printing structures and uneven manufacturing. It also addresses some of the problems associated with existing liquid metal material molding processes, such as cumbersome steps, expensive equipment, and high requirements for substrate materials. This invention offers advantages such as rapid molding, uniform manufacturing, low cost, and strong material adaptability. Attached Figure Description

[0015] Figure 1 This is a schematic diagram of the device structure of a liquid metal micron-wire strain sensor for electrohydraulic inkjet printing according to the present invention.

[0016] Figure 2 This is a schematic diagram of the electric field control module proposed in this invention.

[0017] Figure 3 This is a schematic diagram of the slurry supply module proposed in this invention.

[0018] Figure 4 This is a schematic diagram of the printing motion module proposed in this invention.

[0019] Figure 5 This is a schematic diagram of the structure of the visual observation module proposed in this invention.

[0020] Figure 6 This is a schematic diagram of the static elimination module proposed in this invention.

[0021] Figure 7 This is a schematic diagram of the two-layer TPU film structure of the device to be realized in this invention in the open state.

[0022] Figure 8 This is a schematic diagram of the state structure of the device after hot-pressing and encapsulation of two TPU films as intended by the present invention.

[0023] In the diagram: 1 Electric field control module; 2 Slurry supply module; 3 Printing motion module; 4 Visual observation module; 5 Static electricity elimination module; 11 High-voltage DC power supply; 21 Precision injection pump; 22 Fixed rod assembly; 23 Push plate; 24 Needle container; 31 Three-axis motion platform; 32 Printing substrate; 33 Printhead; 41 Observation camera; 51 Ionizing air bar; 52 High-voltage ion power supply; 53 Fixed support assembly. Detailed Implementation

[0024] The present invention will be further described below with reference to the technical solution and accompanying drawings.

[0025] like Figure 7 , Figure 8 The diagram shown is a schematic of a liquid metal micron-wire strain sensor according to an embodiment of the present invention, wherein, Figure 7 The diagram shows the two TPU films in the open state, with liquid metal microwires printed on one of the TPU films. Figure 8 As shown Figure 7 A schematic diagram of a liquid metal micron-scale strain sensor obtained by hot-pressing another TPU film onto the structure.

[0026] The method for manufacturing this liquid metal micron-wire strain sensor may include the following steps:

[0027] Preparation: Select and prepare a liquid metal paste suitable for electrohydraulic inkjet printing, and select and prepare a pair of flexible films, such as a first TPU film and a second TPU film.

[0028] The liquid metal slurry can be a blend of liquid metal and polymer solvent. A eutectic gallium-indium alloy (EGaIn) can be used as the liquid metal, with a Ga:In weight percentage of 3-4:1 to balance fluidity and stability.

[0029] The polymer solvent can be a polymer with a viscosity of 1~10 cP (centipoise) at 20℃, such as polyethylene oxide (PEO), polydimethylsiloxane (PDMS), or polyvinylpyrrole (PVP). The solvent can be ethylene glycol / propylene glycol / water, and the evaporation rate can be set to be less than 1 mm / s to prevent clogging.

[0030] Liquid metal slurry preparation can be carried out by melting / ultrasonic dispersion of liquid metal; dissolving polymer in solvent; blending the two; and filtering to the desired particle size, such as less than 10 μm, reaching 5 μm.

[0031] Printing of a liquid metal strain monitoring network: including fixing a first TPU film as a printing substrate; forming the liquid metal microwires by high-voltage jet printing under visual monitoring and ion blowing conditions;

[0032] Placement of terminals: Place terminals at both ends of the liquid metal microwires printed on the TPU film substrate, and lead out wires from the terminals.

[0033] Thermo-press encapsulation of the second TPU film: The second TPU film is placed on top of the first TPU film, which has been printed with the micron lines and has terminals placed on it. The two films are then joined together using a thermo-pressing process to complete the encapsulation of the liquid metal micron line strain sensor.

[0034] The above process can be achieved using the following apparatus.

[0035] like Figure 1 As shown, an electrofluid printing device for a liquid metal micron-wire strain sensor includes an electric field control module 1, a slurry supply module 2, a printing motion module 3, a visual monitoring module 4, and an electrostatic elimination module 5. The electric field control module 1 is equipped with a high-voltage DC power supply, enabling adjustment of the electric field strength for electrofluid printing. The slurry supply module 2 includes a precision injection pump, a fixing rod assembly, a push plate, and a needle container, controlling the slurry discharge for electrofluid printing through shaft-hole fitting and pressure control. The printing motion module 3 controls the relative positional relationship between the printing substrate and the printhead to achieve planar forming of the liquid metal micron-wire. The visual monitoring module 4 observes the electrofluid jet state in real time to help make decisions on process parameter adjustments, enabling stable electrofluid printing. The electrostatic elimination module 5 uses the positive and negative charge generation and emission capabilities of an ion bar to neutralize the charge deposited on the first flexible film in real time, preventing the negative impact of deposited charge on the printing jet and the manufacturing structure.

[0036] like Figure 2 As shown, the electric field control module 1 includes a high-voltage DC power supply 11. The output voltage can be changed by adjusting the knob on it. It is connected to the printhead 33 through a wire to apply an electric field to the electro-hydraulic printing motion module 3, thereby controlling the electric field strength of the electro-hydraulic printing.

[0037] like Figure 3 As shown, the slurry supply module 2 includes a precision injection pump 21, a fixing rod assembly 22, a push plate 23, and a syringe container 24. The fixing rod assembly 22 is fixed to the precision injection pump 21. The push plate 23 has through holes that mate with the fixing rod assembly and is mounted thereon. One end of the syringe container 24 is fixed to the fixing rod assembly, and the other end contacts the push plate 23. When the precision injection pump 21 starts working, the push plate 23 is pressurized, pushing the syringe container 24 to move, thereby pushing out the liquid metal slurry within the syringe container 24, thus supplying the raw material for electrohydraulic inkjet printing. By adjusting the relevant parameters of the precision injection pump 21, precise control of the flow rate of the liquid metal slurry for electrohydraulic inkjet printing can be achieved.

[0038] likeFigure 4 As shown, the printing motion module 3 includes a three-axis motion platform 31, a printing substrate 32, and a printhead 33. The printing substrate 32 is fixed to the Y-axis by screws, while the printhead 33 is mounted on the crossbeam of the three-axis motion platform 31 and connected to a high-voltage DC power supply 11 via wires. By controlling the movement of the three-axis motion platform 31 in three spatial directions, various relative movements between the printing substrate 32 and the printhead 33 can be achieved, thereby realizing the planar patterning conversion of electro-hydraulic printing.

[0039] like Figure 5 As shown, the visual observation module 4 includes an observation camera 41. By adjusting the focus of the observation camera to the vicinity of the nozzle 33, the jet state of the liquid metal paste of electrohydraulic printing can be observed. Based on the observed jet state, various printing process parameters can be easily adjusted.

[0040] like Figure 6 As shown, the electrostatic elimination module 5 includes an ion air bar 51, a high-voltage ion power supply 52, and a fixing bracket assembly 53. The ion air bar 51 is fixed to the crossbeam of the three-axis motion platform 31 via the fixing bracket assembly 53, positioning it slightly forward of the nozzle 33. When electrohydraulic inkjet printing to manufacture liquid metal micron-wire structures begins, the high-voltage ion power supply 52 is turned on, activating the ion air bar 51. The ion air bar 51 ionizes the air, generating a large number of positive and negative charges, which are then ejected from the ion emission needle. As the printing substrate 32 passes under the ion air bar 51 along with the three-axis motion platform 31, the ionized ions collide with the first TPU film, canceling out the charges generated on the printing substrate 32 by the high-voltage electric field excited by the high-voltage DC power supply 11 during continuous electrohydraulic inkjet printing. This prevents charge deposition on the first TPU film from affecting subsequent inkjet printing, thus avoiding defects such as discontinuous printing structures and uneven manufacturing. In particular, in the embodiment where EGaIn, PVP as polymer material, and ethylene glycol as solvent are used to blend liquid metal slurry, the use of PVP and ethylene glycol results in low viscosity of liquid metal slurry, amplifying the charge accumulation effect. Therefore, it is necessary to adjust the power of the static elimination module 5 to eliminate charge accumulation.

[0041] The ion bar 51 is positioned further forward of the printhead 33 in the direction of printhead 33's movement, which ensures that the first TPU film eliminates charge accumulation before printing.

[0042] The specific steps for fabricating a 100μm linewidth liquid metal micron-scale strain sensor using this device are as follows. The fabrication methods for liquid metal micron-scale strain sensors with other linewidths are essentially the same, differing only in parameters.

[0043] Step S1: Select and prepare a liquid metal paste suitable for electrohydraulic inkjet printing, such as the liquid metal paste mentioned above; select and prepare a pair of TPU films; and prepare a pair of terminal blocks.

[0044] Step S2: Place the first TPU film onto the printing substrate 32 and fix it in place as the printing base. Replace the printhead with one having an inner diameter of approximately 150 μm and adjust the position of the printhead 33 vertically to a suitable printing height.

[0045] Step S3: The prepared liquid metal slurry is drawn into the syringe container 24, the syringe container is installed on the fixed rod assembly 22, and the push plate 23 is moved to contact the syringe container 24 and the liquid is slightly discharged from the needle.

[0046] Step S4: Adjust the observation camera 41 of the visual observation module 4 so that its focus is near the nozzle 33 so that it can clearly image and observe the electrofluid jet pattern of the liquid metal slurry.

[0047] Step S5: Turn on the precision syringe pump 21 and the high-voltage DC power supply 11, and adjust the flow rate to approximately 20 μL / min. 1 The voltage was maintained at approximately 3.2 kV until a stable cone jet morphology of liquid metal slurry was observed in the observation camera 41. Based on the main structure design of the manufactured liquid metal micron strain sensor, the output flow rate of the precision injection pump 21, the output voltage of the high-voltage DC power supply 11, and the height of the nozzle 33 from the printing substrate 32 were finely adjusted to stabilize the jet diameter at approximately 100 μm.

[0048] Step S6: Connect the high-voltage ion power supply 52, turn on the ion fan bar 51, and confirm that the ion fan bar 51 is working normally.

[0049] Step S7: Control the three-axis motion platform 31 so that the TPU film substrate on the printing substrate 32 completely passes over the nozzle 33 along the X or Y direction, and the conical jet of liquid metal paste prints a stable micron line structure on the first TPU film.

[0050] Step S8: Place terminals at both ends of the liquid metal microwires printed on the first TPU film substrate, and lead out wires from the terminals.

[0051] In step S9, the second TPU film is placed on the first TPU film substrate that has been printed with liquid metal microwires, and the two films are joined together using a hot pressing process to complete the encapsulation of the liquid metal microwire strain sensor.

[0052] In summary, this invention provides an apparatus and method for electrohydraulic inkjet printing of liquid metal micron-wire strain sensors. The apparatus includes an electric field control module, a slurry supply module, an inkjet printing motion module, a visual monitoring module, and an electrostatic elimination module. The electric field control module adjusts the electric field intensity during electrohydraulic inkjet printing; the slurry supply module controls the slurry output; the inkjet printing motion module enables planar forming of the liquid metal micron-wires; the visual monitoring module helps achieve stable electrohydraulic inkjet printing by real-time observation of the electrohydraulic jet state; and the electrostatic elimination module eliminates the negative impact of substrate-deposited charges on the stability and uniformity of the printed structure in real time. This invention solves the negative impacts of substrate-deposited charges on the inkjet printing process, such as discontinuous printing structures and uneven manufacturing, and also addresses the problems of cumbersome forming steps, expensive equipment, and high substrate material requirements in existing liquid metal material processing. It is simple to operate, has a wide range of applications, and can improve manufacturing efficiency in micro / nano manufacturing and flexible electronics fabrication, showing promising application prospects.

Claims

1. A method for electrohydraulic inkjet printing of liquid metal micron-wire strain sensors, characterized in that, A current-current printing fabrication apparatus employing a liquid metal microwire strain sensor includes a liquid metal microwire printed on a first flexible film, terminals connected to the liquid metal microwire, and a second flexible film hot-pressed onto the first flexible film, the liquid metal microwire, and the terminals; the current-current printing fabrication apparatus includes an electric field control module (1), a slurry supply module (2), a printing motion module (3), a visual observation module (4), and an electrostatic elimination module (5); the slurry supply module (2) supplies the raw materials for current-current printing; the printing motion module (3) includes a three-axis motion platform (31), a printing substrate (32), and a printhead (33); wherein the printing substrate (32) is fixed on the Y-axis, and the printhead (33) is mounted on the crossbeam of the three-axis motion platform (31) and connected to a high-voltage DC power supply (11) via a wire; the electric field control module (1) applies an electric field to the current-current printing motion module (3); the visual observation module (4) and the electrostatic elimination module (5) are all included in the apparatus. The observation module (4) observes the jet state of the electrohydraulic inkjet printing and provides the observed jet state to the electric field control module (1) and the slurry supply module (2); the electrostatic elimination module (5) includes an ion air bar (51), a high-voltage ion power supply (52), and a fixed support group (53); the ion air bar (51) is fixed to the crossbeam of the three-axis motion platform (31) through the fixed support group (53), so that it is in a more forward position than the nozzle (33) in the printing direction of the liquid metal micron line; The ion air bar (51) is configured to ionize air to generate a large number of positive and negative charges when electrofluid printing of liquid metal microwire structures begins and eject them from the ion emission needle; such that when the printing substrate (32) passes under the ion air bar (51) with the three-axis motion platform (31), the ionized ions will collide with the first flexible film on the printing substrate (32) and cancel out the charges generated on the first flexible film by the high voltage electric field excited by the electric field control module (1) during the continuous electrofluid printing process; Includes the following steps: Step S1: Select and prepare a liquid metal paste suitable for electrohydraulic inkjet printing; select and prepare a pair of TPU films as the first flexible film and the second flexible film; and prepare a pair of terminals. Step S2: Place the first TPU film on the inkjet printing substrate (32) and fix it as the inkjet printing base; adjust the position of the print head (33) up and down to a suitable inkjet printing height; Step S3: Draw the prepared slurry into the syringe container (24), install the syringe container onto the fixed rod assembly (22), move the push plate (23) to contact the syringe container (24) and make the needle dispense liquid; Step S4: Adjust the observation camera (41) of the visual observation module (4) so ​​that its focus is near the nozzle (33) so that it can clearly image and observe the shape of the electrohydrodynamic jet; Step S5: Turn on the precision injection pump (21) and the high-voltage DC power supply (11), and adjust the flow rate and voltage until a stable cone jet shape is observed in the observation camera (41); according to the main structure design of the manufactured liquid metal micron strain sensor, finely adjust the output flow rate of the precision injection pump (21), the output voltage of the high-voltage DC power supply (11) and the height of the nozzle (33) from the printing substrate (32) to stabilize the jet diameter at the predetermined size; Step S6: Connect the high-voltage ion power supply (52), turn on the ion fan bar (51), and confirm that the ion fan bar (51) is working normally. Step S7: Control the three-axis motion platform (31) to make the first TPU film substrate on the printing substrate (32) completely pass over the nozzle (33) along the X or Y axis direction, and the liquid metal jet prints a stable micron line structure on the first TPU film. Step S8: Place terminals at both ends of the liquid metal microwires printed on the first TPU film substrate, and lead out wires from the terminals. Step S9: Take the second TPU film and cover it on the first TPU film substrate that has been printed with liquid metal microwires. Use a hot pressing process to bond the two films together to complete the encapsulation of the liquid metal microwire strain sensor.

2. The electrofluidic printing method for fabricating a liquid metal micron-wire strain sensor according to claim 1, characterized in that, The electric field control module (1) includes a high-voltage DC power supply (11); by adjusting the knob on it to change the magnitude of the output voltage, it is connected to the nozzle (33) through a wire to apply the electric field to the electro-hydraulic inkjet printing motion module (3); The slurry supply module (2) includes a precision injection pump (21), a fixing rod assembly (22), a push plate (23), and a syringe container (24). The fixing rod assembly (22) is fixed to the precision injection pump (21), and the push plate (23) has a through hole that matches the fixing rod assembly (22) and is mounted thereon. One end of the syringe container (24) is fixed to the fixing rod assembly (22), and the other end is in contact with the push plate (23). When the precision injection pump (21) starts working, the push plate (23) is subjected to pressure and pushes the syringe container (24) to move, thereby pushing out the liquid metal slurry in the syringe container (24).

3. The electrofluidic printing method for fabricating a liquid metal micron-wire strain sensor according to claim 2, characterized in that, The high-voltage DC power supply (11) and the syringe container (24) are connected to the printhead (33) through pipelines and electrical lines, respectively. The voltage and flow rate of the electrofluid printing process are controlled by controlling the output voltage of the high-voltage DC power supply (11) and the mass flow rate of the precision injection pump (21).

4. The electrofluidic printing method for fabricating a liquid metal micron-wire strain sensor according to claim 1, characterized in that, The three-axis motion platform (31) of the printing motion module (3) provides three-way motion in three-dimensional space. The X and Y directions of motion are used to change the spatial position of the printing substrate (32), and the Z direction of motion is used to change the spatial position of the printhead (33). The combination of the two allows the printing substrate (32) and the printhead (33) to reach any relative position in three-dimensional space.

5. The electrofluidic printing method for fabricating a liquid metal micron-wire strain sensor according to claim 1, characterized in that, The electrostatic elimination module (5) is installed above the movement path of the inkjet substrate (32) and does not interfere with the printhead (33).

6. The electrohydraulic inkjet printing method for liquid metal micron-wire strain sensors according to claim 1, characterized in that: The liquid metal slurry is a blend of liquid metal and polymer solvent; wherein a eutectic gallium indium alloy (EGaIn) is used as the liquid metal, and the weight percentage of Ga:In is 3~4:1.

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