Flexible electrode and preparation method

Abstract

The invention relates to the technical field of biological electric conduction, in particular to a flexible electrode and a preparation method thereof.The flexible electrode is prepared from a composite material solution, and the composite material solution comprises (1) a thermoplastic polyurethane elastomer, poly (ethylene glycol adipate), polyether amide, polyacrylonitrile or polyurethane and (2) benzodifuran diketone; wherein the concentration of the elastomer material in the composite material solution is about 2.5%-10% (w / v), and the concentration of the benzodifuran diketone in the composite material solution is about 0.1%-2% (w / v). And the flexible electrode can be prepared by printing by adopting an aerosol spraying technology. The flexible electrode provided by the invention has excellent conductivity and tensile property, and has good application value in the fields of flexible electrodes, brain-computer interfaces and the like.

Description

[0001] Priority application This application claims priority to Chinese patent application No. 2024116761595, filed on November 21, 2024, entitled "A Flexible Electrode and a Method for its Preparation", which is incorporated herein by reference in its entirety. Technical Field

[0002] This invention relates to the field of bioconductive technology, specifically to a flexible electrode and its preparation method. Background Technology

[0003] With the rapid development of cutting-edge technologies such as wearable electronic devices, biomedical sensing, soft robotics, and brain-computer interfaces, traditional rigid electrodes can no longer meet the application requirements of close and comfortable fit with human tissue or dynamic curved surfaces. Flexible electrodes, as a key component capable of withstanding mechanical deformations such as bending, folding, and stretching while maintaining their electrical functions, are playing an increasingly important role. Currently, commonly used flexible electrodes are mainly based on metals and polymers. Metal flexible electrodes have high conductivity, but their inherent ductility is poor, and they are prone to microcracks under small strains, leading to a sharp decline in conductivity or even complete failure. Conductive polymer flexible electrodes have a certain degree of flexibility and stretchability, but suffer from low conductivity. Summary of the Invention

[0004] High-frequency signal transmission or low-signal acquisition can lead to significant signal loss and low signal-to-noise ratio, making it difficult to meet the extremely high signal quality requirements of applications such as brain-computer interfaces. Benzodifuran dione is a highly conductive polymer material, but it is inherently brittle with extremely low elongation at break, making it unsuitable for direct application in flexible electronic devices requiring deformation. The purpose of this invention is to provide a flexible electrode and its preparation method, partially addressing or mitigating the aforementioned shortcomings of the prior art, and enabling the fabrication of an electrode that combines both conductivity and tensile strength.

[0005] To solve the aforementioned technical problems, the present invention specifically adopts the following technical solution: A first aspect of the present invention is to provide a flexible electrode, the flexible electrode being prepared by means of a composite material solution, the composite material solution comprising: (1) an elastomer material, wherein the type of the elastomer material includes one or more of the following: urethane elastomer, polyethylene adipate, polyetheramide, polyacrylonitrile, polyurethane; and (2) benzodifurandione; The concentration of the elastomer material in the composite material solution is 2.5%-10% (w / v), and the concentration of the benzodifurandione in the composite material solution is 0.1%-2% (w / v).

[0006] In some embodiments, the concentration of the elastomer material in the composite material solution is 3%-5% (w / v); the concentration of the benzodifuran dione in the composite material solution is 1%-2% (w / v).

[0007] In some embodiments, the structure of the flexible electrode includes at least one of the following types: sheet-like, mesh-like, and strip-like.

[0008] In some embodiments, the flexible electrode further includes an active functional component; In some embodiments, the flexible electrode is configured as a bioelectrical interface, and the bioelectrical interface includes one or more of an electroencephalogram (EEG) interface, an electromyogram (EMG) interface, and an electrocardiogram (ECG) interface.

[0009] The present invention also provides a composite material, wherein the composite material is a composite material solution or is made from the composite material solution, the composite material solution comprising: (1) an elastomer material, and the type of the elastomer material includes one or more of the following: urethane elastomer, poly(ethylene adipate), polyetheramide, polyacrylonitrile, polyurethane; and (2) benzodifuran dione; The concentration of the elastomer material in the composite material solution is 2.5%-10% (w / v), and the concentration of the benzodifurandione in the composite material solution is 0.1%-2% (w / v).

[0010] In some embodiments, the concentration of the elastomer material in the composite material solution is approximately 3%-5% (w / v); the concentration of the benzodifurandione in the composite material solution is approximately 1%-2% (w / v).

[0011] The present invention also provides a preparation method, comprising the steps of: Obtain at least one elastomer material to be tested, and test the intermolecular forces between the elastomer material and benzodifurandione; Determine whether the intermolecular forces are greater than a set threshold force; if so, then use the elastomer material to be tested as the recommended elastomer material. The recommended elastomer material is mixed with benzodifurandione.

[0012] This invention also provides a method for preparing a flexible electrode, comprising the following steps: S1 provides a composite material solution as described in any one of the embodiments; S2 uses an aerosol jetting device to atomize the composite material solution, so that the composite material solution is converted into a number of droplets; S3 causes the plurality of droplets to be deposited on the substrate at a first velocity of 0.0005-10 µL / mm² / s.

[0013] In some embodiments, the droplets are droplet jets with a width on the micrometer scale; and / or, prior to S2, the step further includes: The composite material solution is subjected to a mixing process, wherein the mixing process includes magnetic stirring, vortexing, or ultrasonic mixing.

[0014] In some embodiments, the steps further include: Obtain the three-dimensional digital model to be formed; The three-dimensional digital model is cut to obtain multiple slice layers. The corresponding spray pattern is obtained based on the slice layer, and the spray pattern is associated with a set spray sequence or spray time; Correspondingly, in S3, the aerosol spraying device sprays the spray pattern onto the substrate sequentially according to the spraying order or the spraying time to form it layer by layer.

[0015] In some embodiments, the method further includes the step of: During the molding process, the first molding speed of the molding structure on the substrate is monitored within a first time period; When the first forming speed is less than the first set forming speed, the first speed will be reduced to obtain the second speed. Correspondingly, the aerosol jetting device will use the second speed for printing.

[0016] In some embodiments, the steps further include: The second forming speed of the formed structure on the substrate will continue to be monitored during the next second time period. When the second forming speed is greater than or equal to the second set forming speed, the second speed is maintained to continue inkjet printing.

[0017] In some embodiments, the method further includes the step of: During the next second time period, the second forming speed of the already formed structure on the substrate during the first time period will continue to be monitored. When the second molding speed is less than the second set molding speed, it is recommended that the user update the slicing results again; the slicing results include: the number of slice layers and the thickness of the slice layers.

[0018] Beneficial technical effects: It is worth noting that although some existing technologies have attempted to mix elastomeric materials (or simply elastomers) and conductive materials to create bioelectrodes, there are significant obstacles to the mixing of these materials. Consequently, the types of existing composite material systems are very limited, which in turn restricts the application of bioelectrodes.

[0019] Taking the mixing of PBFDO and elastomer materials as an example, the rigid structure of PBFDO is brittle and not easily bent. Therefore, when PBFDO and elastomer materials are mixed, the rigid segments of PBFDO may severely restrict the movement and stretching of molecular chains in the elastomer, resulting in the composite material being unable to possess both electrical conductivity and tensile strength.

[0020] In response, the applicant creatively mixed PBFDO at a specific concentration range with several special elastomer materials at a specific concentration range to prepare a composite material with both excellent electrical conductivity and tensile strength.

[0021] Preferably, a composite material (or flexible electrode) is prepared by mixing PBFDO with TPU at a specific concentration.

[0022] Preferably, the composite material is sprayed using an aerosol spraying process, which further improves the mixing uniformity of the composite material and ensures that the prepared electrode has significant advantages in conductivity and tensile strength.

[0023] Furthermore, in order to achieve the mass production of flexible electrode materials, a limiting parameter tuning process is also provided to maintain the quality stability of the products during long-term, high-volume printing. Attached Figure Description

[0024] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. In all the drawings, similar elements or parts are generally identified by similar reference numerals. The elements or parts in the drawings are not necessarily drawn to scale. Obviously, the drawings described below are some embodiments of the present invention, and those skilled in the art can obtain other drawings based on these drawings without any creative effort.

[0025] Figure 1a This is a schematic diagram of the fabrication process of a flexible electrode in an exemplary embodiment of the present invention; Figure 1b The molecular formula of PBFDO; Figure 2 This is a schematic diagram of the microstructure of a flexible electrode. Figure 3 This is a schematic diagram illustrating the stretching effect of a flexible electrode. Figure 4 A schematic diagram of a flexible electrode product; Figure 5 This is a schematic diagram of the conductivity test for a flexible electrode. Figure 6Electrode products prepared using aerosol jet printing to fabricate flexible electrodes; Figure 7 Electrode products prepared by electrospinning; Figure 8 Electrode products prepared using other molding methods. Detailed Implementation

[0026] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0027] In this document, suffixes such as "module," "part," or "unit" used to denote elements are used only for the purpose of illustrative purposes and have no specific meaning in themselves. Therefore, "module," "part," or "unit" may be used interchangeably.

[0028] In this document, the terms "upper," "lower," "inner," "outer," "front," "rear," "one end," and "the other end," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing the present invention and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the present invention. Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0029] In this document, unless otherwise explicitly specified and limited, the terms "installed," "equipped with," "connected," etc., should be interpreted broadly. For example, "connection" can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection, a direct connection, or an indirect connection through an intermediate medium; it can be a connection within two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0030] In this document, "and / or" includes any and all combinations of one or more of the listed related items.

[0031] In this article, "multiple" means two or more, that is, it includes two, three, four, five, etc.

[0032] As used in this specification, the term "about" typically means + / -5% of the value, more typically + / -4% of the value, more typically + / -3% of the value, more typically + / -2% of the value, even more typically + / -1% of the value, and even more typically + / -0.5% of the value.

[0033] In this specification, certain embodiments may be disclosed in a range-bound format. It should be understood that this "range-bound" description is merely for convenience and brevity and should not be construed as a rigid limitation on the disclosed range. Therefore, the description of a range should be considered as having specifically disclosed all possible subranges and the individual numerical values ​​within those ranges. For example, a description of the range 1-6 should be considered as having specifically disclosed subranges such as from 1 to 3, from 1 to 4, from 1 to 5, from 2 to 4, from 2 to 6, from 3 to 6, etc., and the individual numbers within those ranges, such as 1, 2, 3, 4, 5, and 6. This rule applies regardless of the breadth of the range.

[0034] Currently, in existing technologies, electrode materials typically have poor tensile properties, making them unsuitable for biomedical applications. For example, when applied to brain-computer interfaces, they are difficult to fit perfectly. Similarly, when applied to wearable devices, they are difficult to adapt to the wearer's limb characteristics or specific activities.

[0035] To solve the above technical problems, see Figures 1a-5 As shown, this invention provides a flexible electrode prepared from a composite material solution, the composite material solution comprising: an elastomer material and a benzodifuran dione; wherein the elastomer material is preferably a thermoplastic polyurethane elastomer. An exemplary preparation process for the flexible electrode is as follows: Figure 1a As shown.

[0036] In the composite material solution system, the concentration of polyurethane elastomer (TPU) is approximately 2.5%-10%; the concentration of PBFDO is approximately 0.1%-2%. Figure 2 The molecular structure of PBFDO is shown.

[0037] In the composite material solution system: the concentration of the polyurethane elastomer (i.e., TPU) is preferably about 3%-5% (w / v); the concentration of the benzodifuran dione (i.e., PBFDO) is preferably about 1%-2% (w / v).

[0038] For example, in some embodiments, a TPU solution concentration in the range of approximately 6%-10% (w / v) can be used, and the TPU solution can be mixed with a PBFDO solution at approximately 1:1 to obtain a composite material solution with a final TPU concentration of approximately 3%-5% (w / v).

[0039] The bio-flexible conductive materials (such as flexible electrodes) provided by this invention also include active functional components, such as drugs and cytokines.

[0040] In some embodiments, DMF (dimethylformamide) or DMSO (dimethyl sulfoxide) can be used as solvents to dissolve PBFDO and TPU in the solvent, respectively.

[0041] In some embodiments, the composite material solution may be mixed before being used to prepare the electrode, and the mixing process may be one or more of the following: Magnetic stirring, vortexing, and ultrasound.

[0042] In some embodiments, the flexible electrodes provided by the present invention can be applied to electroencephalography (EEG), electromyography (EMG), electrocardiography (ECG), or neural signal acquisition.

[0043] In some embodiments, the flexible electrode provided by the present invention can also be used to achieve electrical stimulation.

[0044] In some embodiments, the structure of the flexible electrode includes at least one of the following types: sheet-like, mesh-like, strip-like, etc. Figures 3-5 As shown. Figure 5 The printed conductive materials with different line widths are shown, with conductivity of approximately 1100 S / m and 620 S / m, respectively, indicating good conductivity.

[0045] In this context, "sheet-like" typically refers to an object in three-dimensional space where one dimension (usually thickness) is much smaller than the other two dimensions (length and width), resulting in a flat, thin sheet-like shape. "Strip-like," on the other hand, refers to an object in three-dimensional space where one dimension (length) is much larger than the other two dimensions (width and thickness), resulting in a long, thin shape, such as... Figure 3 As shown. A network refers to a structure with a large number of gaps, formed by the intersection and connection of multiple lines or strips.

[0046] It is understood that the geometry and size of the flexible electrode can be adaptively adjusted according to the actual application scenario or application specifications, and the present invention does not impose any limitations on this. For example, when the flexible electrode is used as a wire, it can typically be configured as a strip.

[0047] In another respect, the present invention also provides a composite material, which is a composite material solution or made from the composite material solution, the composite material solution comprising: (1) an elastomer material, and the type of the elastomer material includes one or more of the following: urethane elastomer (TPU), polyethylene adipate (PEA), polyether amide (PEBA), polyacrylonitrile (PAN), polyurethane (PU); and (2) benzodifuran dione (PBFDO); The concentration of the elastomer material in the composite material solution is approximately 2.5%-10% (w / v), and the concentration of the benzodifurandione in the composite material solution is approximately 0.1%-2% (w / v).

[0048] Preferably, in some embodiments, the concentration of the elastomer material in the composite material solution is approximately 3%-5% (w / v); and the concentration of the benzodifurandione in the composite material solution is approximately 1%-2% (w / v).

[0049] For example, in some embodiments, the composite material is a composite solution, in which case the composite material can be used as printing ink.

[0050] For example, in some embodiments, the composite material may also be a conductive material obtained by processing (e.g., mixing) or molding a composite material solution, such as a sheet, strip, or mesh conductive material.

[0051] Preferably, the present invention also provides a method for preparing a flexible electrode, comprising the steps of: S1 provides the composite material solution; For example, in some embodiments, the composite material is composed of a mixture of benzodifuran dione and an elastomer material.

[0052] Preferably, before preparing the composite material, the method further includes the following steps: Obtain at least one elastomer material to be tested, and test the intermolecular forces between the elastomer material and benzodifurandione; Determine whether the intermolecular forces are greater than a set threshold force; if so, then use the elastomer material to be tested as the recommended elastomer material. The recommended elastomer material is mixed with benzodifurandione.

[0053] In this embodiment, the prediction of intermolecular forces can, to a certain extent, ensure the degree of mixing between the elastomer material and benzodifurandione, or in other words, ensure the bonding strength between the two, thereby comprehensively improving the conductivity and tensile properties of the composite material.

[0054] S2 uses an aerosol jetting device to atomize the composite material solution, converting the composite material solution into several droplets; S3 causes the plurality of droplets to be deposited on the substrate at a first velocity, which is 0.0005-10 µL / mm² / s. Here, the velocity (such as the first velocity or the second velocity) in this embodiment refers to the printing flow rate per unit area per unit time.

[0055] In some embodiments, the printing flow rate can be set between 1 and 100 µL / h, and the moving speed of the deposition head is typically between 1 and 20 mm / s.

[0056] Of course, in other embodiments, if higher requirements are placed on the forming accuracy of the flexible electrode, the deposition head speed of the printing device can be set to about 0.1 mm / s. Alternatively, in other embodiments, if the forming accuracy requirements of the flexible electrode are relatively small, such as when printing large areas quickly, the moving speed of the deposition head may reach 50-100 mm / s.

[0057] To reduce the impact of airborne particulate contaminants on the printing process and improve print quality, it is preferable to operate in a cleanroom environment (typically an ISO 6–8 cleanroom) to minimize the influence of dust and impurities on the print results.

[0058] Preferably, the ambient humidity during the printing process is maintained within the range of 30–60% to avoid excessive humidity which may cause changes in surface tension after material deposition, affecting the shape of the pattern, while also avoiding excessively low humidity which may cause some aerosol materials to evaporate too quickly, leading to printing instability.

[0059] Preferably, the temperature during the printing process is set to a constant temperature, such that the temperature fluctuation does not exceed approximately 2°C.

[0060] Preferably, strong airflow or air disturbance (such as direct airflow from an air conditioner or excessive ventilation from the equipment) should be avoided in the environment. The maximum air velocity (or average air velocity) should be set to be less than a set threshold. Specifically, it can be set in combination with printing environment conditions, such as temperature and humidity.

[0061] Preferably, static electricity buildup should be avoided in the printing environment, especially when printing high-resolution, microstructured, or conductive materials. Static elimination devices or anti-static desktops can be used.

[0062] In some embodiments, the droplets are droplet jets with a width on the micrometer scale. In some embodiments, prior to S2, the following step is also included: The composite material solution is then mixed.

[0063] In some embodiments, prior to S2, the following step is also included: The mixing process includes magnetic stirring, vortexing, or ultrasound.

[0064] In some embodiments, the steps further include: Obtain the three-dimensional digital model to be formed; The three-dimensional digital model is cut to obtain multiple slice layers. The corresponding spray pattern is obtained based on the slice layer, and the spray pattern is associated with a set spray sequence or spray time; Correspondingly, in S3, the aerosol spraying device sprays the spray pattern onto the substrate sequentially according to the spraying order or the spraying time to form it layer by layer.

[0065] In some embodiments, the steps further include: During the molding process, the first molding speed (i.e., curing speed) of the molded structure on the substrate is monitored within the first time period. For example, in some embodiments, multiple images of the formed structure within a first time period can be captured by a camera device, and the corresponding forming speed can be calculated by comparing the images.

[0066] For example, in some embodiments, edge information of the structure in the image (such as edge sharpness, such as the clear boundary lines of the solidified structure, and the corresponding boundary line information - such as coordinates - can be identified by image processing technology, and the forming speed between two images can be identified by comparing the boundary lines).

[0067] When the first forming speed is less than the first set forming speed, the first speed will be reduced to obtain the second speed. Correspondingly, the aerosol jetting device will use the second speed for printing.

[0068] For example, in some embodiments, when a slightly low forming speed is detected, the printing speed can be appropriately slowed down (i.e., printing can be performed at a lower second speed).

[0069] In some embodiments, the steps further include: The second forming speed of the formed structure on the substrate will continue to be monitored during the next second time period. When the second forming speed is greater than or equal to the second set forming speed, the second speed is maintained to continue inkjet printing.

[0070] In this embodiment, in order to ensure that the adjustment of the printing speed is reliable, the printing effect after adjustment can be continuously monitored. If the adjusted forming speed meets the preset requirements, the current speed can be maintained to continue to complete the subsequent printing work.

[0071] In some embodiments, the steps further include: The second forming speed of the formed structure on the substrate will continue to be monitored during the next second time period. When the second molding speed is less than the second set molding speed, it is recommended that the user update the slicing results again; the slicing results include: the number of slice layers and the thickness of the slice layers.

[0072] It is understood that the settings used in this invention, such as the setting of molding speed and other parameters, can be preset by the user or selected by the user in combination with actual printing needs.

[0073] In this embodiment, if the molding speed is still not up to standard after adjustment and updating, the user can be advised to readjust the slicing results in the next printing process.

[0074] For example, when the molding speed is too slow, the number of slices can be increased appropriately (or the thickness of one slice can be reduced).

[0075] In fact, the large-scale fabrication of flexible electrodes typically involves two major application stages: (1) Pre-printing stage, that is, the user conducts multiple pre-experiments with multiple sets of different printing parameters (or different printing conditions), and selects suitable printing parameters (such as printing speed, unit jet volume, moving path, moving speed, etc.) and printing environment (such as temperature, humidity, etc.) in combination with the actual quality of the flexible electrode (such as conductivity, tensile strength, etc.). (2) In the actual printing stage, the selected printing parameters and printing environment are used as the initial printing conditions for batch printing.

[0076] However, the applicant noted that when using aerosol jetting equipment to print flexible electrodes in large batches over a long period of time, the printing parameters or printing environment (such as humidity) are often prone to fluctuations, which may lead to a significant reduction in the final product quality of the flexible electrode (such as molding quality, tensile strength, and conductivity).

[0077] In response to the situation where there are slight fluctuations in printing parameters or one or more factors in the printing environment, this invention provides a restrictive automated parameter tuning mechanism. This restrictive parameter tuning mechanism can maintain the product quality of flexible electrodes while minimizing damage or interference to the initial printing conditions.

[0078] From another perspective, this restrictive mode can reduce the difficulty of automated parameter tuning (such as reducing the difficulty of decision-making), and on the other hand, it can reduce or avoid the introduction of new uncertainties in the correction process, which would instead increase the complexity of the printing process.

[0079] Specifically, the limiting parameter tuning mechanism provided by this invention may include the following process: (1) Obtain the three-dimensional digital model to be formed; (2) The three-dimensional digital model is cut to obtain multiple slice layers; (3) Obtain the corresponding standard spraying pattern based on the sliced ​​layer; (4) During the printing process, the first spray image corresponding to the slice layer at the current moment (such as a real photo captured by an image device) is obtained, and the second spray image at the previous moment is obtained (such as a real photo corresponding to the previous slice layer, or a real photo of the current slice layer at the previous moment). (5) Generate a first degree of deviation and a second degree of deviation based on the first spray image, the second spray image and the corresponding standard spray pattern (hereinafter referred to as the standard pattern); (6) Generate the first deviation risk based on the first deviation degree and the second deviation degree; (7) Select a correction scheme based on the first deviation risk.

[0080] For example, in some embodiments, the degree of deviation can be classified into Level 1 and Level 2 based on the magnitude of the difference between the sprayed image and the standard pattern, from smallest to largest. Exemplarily, the difference between the sprayed pattern and the standard pattern can be identified using image recognition technology. For example, the difference can be comprehensively evaluated by the morphological differences and area differences between the sprayed image (such as a photograph) and the standard pattern, or the difference can also be evaluated by the edge sharpness obtained by comparing the sprayed pattern and the standard pattern.

[0081] If both the first and second deviation levels are at level one, the deviation risk is level one; if one of the first and second deviation levels is at level one and the other is at level two, the deviation risk is level two; if both the first and second deviation levels are at level two, the deviation risk is level three.

[0082] Understandably, in some embodiments, during the initial pre-printing stage, the user will execute and record multiple sets of different printing conditions. Specifically, the user can also record the correction schemes adopted under different printing states (such as when the formed pattern deviates), and the final correction results obtained by executing different correction schemes (such as improved quality, no significant change, etc.). Based on this recorded historical data, the correspondence between different deviation levels and deviation risks can be statistically analyzed in advance, as well as the recommended correction strategies for different deviation risks.

[0083] In some embodiments, the step of selecting a correction scheme based on the deviation risk includes: When the deviation risk falls within the first risk range (e.g., deviation risk is level one), a first suggestion signal is generated. The first suggestion signal suggests parameter correction in a parameter tuning category, which includes at least one of the following: printing speed, temperature, humidity, and vacuum suction pressure. When the deviation risk falls within the second risk range (e.g., the deviation risk is level two), a second recommendation signal is generated. The second recommendation signal suggests parameter correction in a second-class parameter tuning category, which includes at least one of the following: ultrasonic vibration power and jet speed.

[0084] Printing speed refers to the moving speed of the printhead (or deposition head, deposition nozzle), while ejection speed refers to the average axial velocity of aerosol particles ejected from the printhead, which is mainly determined by the sheath gas flow rate.

[0085] Among them, ultrasonic vibration power is mainly used for the atomization rate of ink (i.e., composite material solution) and the initial droplet size distribution.

[0086] Vacuum suction pressure is an auxiliary printing parameter whose main function is to remove splashed droplets and ensure a clean pattern. In other words, vacuum suction pressure can be used to adjust the edge sharpness and fidelity of the pattern.

[0087] Furthermore, in some embodiments, the step of selecting a correction scheme based on the deviation risk further includes: After adjusting the parameters according to one type of parameter tuning, continue to monitor the second deviation risk in the next time period (understandably, the generation scheme of the second deviation risk is the same as that of the first deviation risk). The degree of risk reduction is calculated based on the first and second deviation risks. When the degree of risk reduction is greater than the preset risk threshold, one parameter tuning category will continue to be used as the recommended parameter tuning category. When the degree of risk reduction is less than or equal to a preset risk threshold, a second suggestion signal is generated, which suggests updating the parameter tuning category.

[0088] In other words, in this embodiment, the correction process can be continuously monitored so that the correction plan can be updated in a timely manner when the correction effect is not as expected (e.g., the degree of risk reduction is less than or equal to the risk threshold, which indicates that the correction effect is not obvious).

[0089] Furthermore, in some embodiments, the step of selecting a correction scheme based on the deviation risk includes: When the deviation risk falls within the third risk range (e.g., deviation risk is level three), a third recommendation signal is generated. The third recommendation signal suggests parameter correction in three parameter adjustment categories, which include: atomizer and nozzle alignment status.

[0090] In this embodiment, the aerosol jetting device includes an atomizer for generating aerosol and a deposition head for focusing and depositing the aerosol onto a substrate. The atomizer and deposition head are typically two separate modules connected by a transfer tube. During long-term operation of the aerosol jetting device, when the position and angle of the atomizer are matched with the deposition head, a stable and centered aerosol jet can be formed to achieve stable printing.

[0091] It is worth noting that the present invention preferably targets the special composite material system of TPU and PBFDO, and provides a printing method for controlling the overall uniformity of material forming during the printing process based on restrictive parameter adjustment.

[0092] In particular, this invention selects three sets of parameter tuning categories for progressive adjustment, with the three sets of parameter tuning categories increasing progressively in terms of adjustment difficulty and impact.

[0093] In this embodiment, the focus is on controlling the uniformity of the elastomer material and PBFDO during the molding process using adjustable parameters in different dimensions.

[0094] Specifically, the present invention preferably uses simple parameters such as printing speed, environmental factors (such as temperature and humidity), or vacuum suction pressure to initially adjust the final molding speed. These simple parameters refer to those that are relatively easy to adjust, such as those that are relatively simple to adjust and calculate.

[0095] Furthermore, since preliminary adjustments cannot meet the adjustment requirements, this invention can attempt to achieve a deeper level of control over the uniformity of the molding process from the raw material port (i.e., the particle size of the solution, the amount of spray, etc.) by using ultrasonic vibration power and spray speed.

[0096] Furthermore, if neither of the current two types of adjustments can meet the adjustment expectations, adjustments will be made from unconventional parameters—the core injection structure (atomizer, nozzle alignment)—to avoid affecting the final product's molding quality or performance due to operational deviations of the aerosol injection device.

[0097] In summary, this invention provides a restrictive correction mechanism from conventional to unconventional parameters. This gradual progression from conventional to unconventional parameters is essentially a switch from being dominated by molding speed to being dominated by molding uniformity. In other words, this invention is actually based on the selection of restrictive parameters to achieve a switch in a restrictive-dominant control mode (e.g., when adjusting simple parameters such as printing speed and temperature, molding speed is the dominant factor in controlling the printing process; when adjusting parameters such as ultrasonic vibration power and jetting speed, uniformity is the dominant factor in controlling the printing process).

[0098] This restrictive correction mechanism, which shifts from conventional to unconventional parameters (or, in other words, the mechanism that switches from the dominant factor of forming speed to forming uniformity), can maintain the quality of printed products while minimizing interference with the original printing mode.

[0099] In other words, the restrictive correction mechanism provided by the invention can minimize pattern fluctuations during the printing process, thereby avoiding the introduction of new uncertainties due to corrections, which could increase the difficulty of printing.

[0100] To verify the superior performance of the aforementioned flexible electrode, see [link to relevant documentation]. Figures 2-5 As shown, the flexible electrode prepared by the above method has both conductivity and stretchability. The TPU concentration used is 5% w / v and the PBFDO concentration is 0.5% w / v.

[0101] Table 1 Examples of preparation and testing of PBFDO and TPU Table 1 shows the test results of electrode samples prepared by the mold method (silicone mold after plasma treatment). It can be seen that by combining PBFDO and TPU, an electrode material with both conductivity and tensile properties was unexpectedly prepared.

[0102] Furthermore, through comparative testing, the applicant noted that the electrode samples prepared using aerosol spraying technology exhibited significant advantages in conductivity and tensile strength compared to those prepared using the molding method. The applicant believes this is likely because the spraying process allows TPU to be more uniformly incorporated into PBFDO, thereby reducing defects in the composite material and improving overall strength performance.

[0103] See Figure 6As shown, this is an electrode circuit fabricated using aerosol jetting technology. It can be seen that the circuit structure is uniform (e.g., clear edge structure and uniform width). Furthermore, after conductivity testing, it was determined that it meets application requirements.

[0104] Comparative experiments show that the composite of TPU and PBFDO exhibits unexpected and outstanding advantages in terms of electrical conductivity and tensile properties.

[0105] Test 1: After molding by combining PEGDA and PBFDO, the material becomes conductive after the solvent evaporates, but it lacks flexibility and will break when bent or stretched.

[0106] Test 2: After molding using F127DA and PBFDO composites, the material can be stretched but is not conductive.

[0107] Additionally, Table 2 below provides test results for conductive materials prepared using other molding methods. In Table 2, the TPU concentration used was 5% w / v, and the PBFDO concentration was 0.5% w / v. The corresponding test diagram for Table 2 is shown below. Figure 8 As shown, the flexible electrode prepared by the film-forming method has relatively lower uniformity of electrode forming, conductivity, and tensile strength compared to the flexible electrode prepared by the aerosol jetting technique.

[0108] Figure 7 The conductive material prepared by electrospinning based on the same composite material solution shows that the grid lines are printed with uneven thickness, resulting in poor molding effect and failing to meet conductivity requirements.

[0109] Specifically, the test results in Table 2 can also be found in [reference needed]. Figure 8As shown in the figure. In comparison, it can be seen that the material selection based on PBFDO and TPU in this invention, combined with aerosol jet printing technology, can significantly improve the doping uniformity of PBFDO and TPU, thereby preparing a flexible electrode with excellent tensile strength and conductivity. It is worth noting that in existing technologies, although attempts have been made to mix conductive polymers and elastic materials to prepare bio-flexible conductive materials that balance excellent conductivity, mechanical properties, and biocompatibility, other methods have been employed. For example, PEDOT:PSS (e.g., Chinese patent applications CN115957181A and CN111154120A) can be added to polyether F127-diacrylate hydrogel, or PEDOT:PSS solution can be mixed with other polymers (e.g., polyethylene glycol dimethacrylate) and then polyether F127-diacrylate can be added as a dopant (e.g., Chinese patent application CN118079037A), or polyether F127-diacrylate and PEDOT:PSS can be mixed and then dopamine hydrochloride and sodium hydroxide can be added (e.g., Chinese patent application CN115957181A).

[0110] However, these existing technologies typically have low electrical conductivity (e.g., below 10 S / m, such as around 2 S / m), and therefore can only be used as patch layers for in-situ injection of hydrogels or electrodes, and cannot be used to fabricate flexible bioelectrodes.

[0111] Furthermore, the existing material systems for bioelectrodes are very limited. Because mixing elastomers and conductive materials presents extremely high challenges, the resulting composite materials often fail to possess both elasticity and conductivity; in fact, both properties are often significantly reduced, hindering further applications.

[0112] For example, the applicant noted, particularly with PBFDO and TPU, that PBFDO's molecular backbone is typically designed to be highly rigid and planar to achieve high charge mobility, promoting the delocalization and transport of π-electrons. This rigid structure makes it brittle and difficult to bend. TPU, on the other hand, provides elasticity through its softer polyester or polyether segments. Therefore, during the mixing process, the rigid segments of PBFDO severely restrict the movement and stretching of the TPU molecular chains; simultaneously, there are no strong chemical bonds (such as covalent bonds) or strong physical interactions (such as hydrogen bonds) between the PBFDO and TPU molecular chains. This weak interfacial bonding leads to at least the following defects in the composite material: 1) Deterioration of mechanical properties: During stretching, cracks easily initiate and propagate at the PBFDO / TPU interface; 2) Unstable electrical properties: Once the material is stretched or bent, the contact between PBFDO particles is rapidly lost, leading to a sharp increase in resistance or even a complete open circuit.

[0113] In response, this application creatively selects TPU and PBFDO within a specific concentration range for mixing, thereby unexpectedly breaking through the barriers in the mixing process of TPU and PBFDO, so that the mixed composite material has both excellent conductivity and tensile properties.

[0114] Furthermore, for composite materials formed by TPU and PBFDO within a specific concentration range, this invention creatively introduces an aerosol jetting process for printing preparation, thereby further improving the doping uniformity of the composite material system, that is, further improving the conductivity and tensile properties of the composite material.

[0115] The applicant believes that the long-chain molecular structure and excellent microscopic phase separation properties of the elastomer TPU provide continuous network support and stress dispersion points for the brittle PBFDO molecules. Furthermore, the aforementioned tests have proven that TPU can be effectively compounded with PBFDO, successfully endowing PBFDO materials with superior elasticity and flexibility. Therefore, the applicant believes that other elastomer materials with similar soft / hard segment structures (such as TPU, PEA, PEBA, PU) or strongly polar groups (such as -CN in PAN) also possess the potential to be compounded with PBFDO and impart elasticity to it.

[0116] Therefore, the aforementioned multi-composite material systems can ultimately exhibit the characteristics of PBFDO while also possessing the flexibility and stretchability of elastomer materials.

[0117] In other embodiments, when the requirements for the conductivity and tensile properties of the electrodes change, the elastomer material may be replaced with one or more of the following types: polyethylene adipate (PEA), polyetheramide (PEBA), polyacrylonitrile (PAN), and polyurethane (PU).

[0118] Preferably, in some embodiments, the composite material (or composite material solution) may include a first elastomer, which is TPU, and a second elastomer, the second elastomer being polyethylene adipate (PEA), polyetheramide (PEBA), polyacrylonitrile (PAN), or polyurethane (PU), wherein the concentration of the first elastomer is higher than the concentration of the second elastomer. The concentrations of the first and second elastomers are approximately 2.5%-10% (w / v). Further, the concentrations of the first and second elastomers are approximately 3%-5% (w / v).

[0119] It should be noted that, in this document, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Unless otherwise specified, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes that element.

[0120] Through the above description of the embodiments, those skilled in the art can clearly understand that the methods of the above embodiments can be implemented by means of software plus necessary general-purpose hardware platforms. Of course, they can also be implemented by hardware, but in many cases the former is a better implementation method. Based on this understanding, the technical solution of the present invention, or the part that contributes to the prior art, can be embodied in the form of a software product. This computer software product is stored in a storage medium (such as ROM / RAM, magnetic disk, optical disk) and includes several instructions to cause a computer terminal (which may be a mobile phone, computer, server, or network device, etc.) to execute the methods described in the various embodiments of the present invention.

[0121] The embodiments of the present invention have been described above with reference to the accompanying drawings. However, the present invention is not limited to the specific embodiments described above. The specific embodiments described above are merely illustrative and not restrictive. Those skilled in the art can make many other forms under the guidance of the present invention without departing from the spirit and scope of the claims. All of these forms are within the protection scope of the present invention.

Claims

1. A flexible electrode, characterized in that, The flexible electrode is prepared using a composite material solution, which includes: (1) an elastomer material, and the type of the elastomer material includes one or more of the following: urethane elastomer, poly(ethylene adipate), polyetheramide, polyacrylonitrile, polyurethane; and (2) benzodifuran dione. The concentration of the elastomer material in the composite material solution is 2.5%-10% (w / v), and the concentration of the benzodifurandione in the composite material solution is 0.1%-2% (w / v).

2. The flexible electrode according to claim 1, characterized in that, The concentration of the elastomer material in the composite material solution is 3%-5% (w / v); the concentration of the benzodifuran dione in the composite material solution is 1%-2% (w / v).

3. The flexible electrode according to claim 1, characterized in that, The flexible electrode has a structure including at least one of the following types: sheet-like, mesh-like, or strip-like; And / or, the flexible electrode further includes active functional components; And / or, the flexible electrode is configured as a bioelectrical interface, and the bioelectrical interface includes one or more of electroencephalogram (EEG), electromyography (EMG), and electrocardiogram (ECG).

4. A composite material, characterized in that, The composite material is a composite material solution or is made from the composite material solution, the composite material solution comprising: (1) an elastomer material, and the type of the elastomer material includes one or more of the following: urethane elastomer, poly(ethylene adipate), polyetheramide, polyacrylonitrile, polyurethane; and (2) benzodifuran dione; The concentration of the elastomer material in the composite material solution is 2.5%-10% (w / v), and the concentration of the benzodifurandione in the composite material solution is 0.1%-2% (w / v).

5. A composite material according to claim 4, characterized in that, The concentration of the elastomer material in the composite material solution is approximately 3%-5% (w / v); the concentration of the benzodifuran dione in the composite material solution is approximately 1%-2% (w / v).

6. A preparation method, characterized in that, Including the following steps: Obtain at least one elastomer material to be tested, and test the intermolecular forces between the elastomer material and benzodifurandione; Determine whether the intermolecular forces are greater than a set force threshold. If so, the elastomer material to be tested shall be used as the recommended elastomer material; The recommended elastomer material is mixed with benzodifurandione.

7. A method for preparing a flexible electrode, characterized in that, Including the following steps: S1 provides the composite material solution as described in claim 4 or 5; S2 uses an aerosol jetting device to atomize the composite material solution, so that the composite material solution is converted into a number of droplets; S3 causes the plurality of droplets to be deposited on the substrate at a first velocity of 0.0005-10 µL / mm² / s.

8. The preparation method according to claim 7, characterized in that, The droplets are droplet jets with a width on the micrometer scale; and / or, prior to S2, the step further includes: The composite material solution is subjected to a mixing process, wherein the mixing process includes magnetic stirring, vortexing, or ultrasonic mixing.

9. The preparation method according to claim 7, characterized in that, It also includes the following steps: Obtain the three-dimensional digital model to be formed; The three-dimensional digital model is cut to obtain multiple slice layers. The corresponding spray pattern is obtained based on the slice layer, and the spray pattern is associated with a set spray sequence or spray time; Correspondingly, in S3, the aerosol spraying device sprays the spray pattern onto the substrate sequentially according to the spraying order or the spraying time to form it layer by layer; And / or, the method further includes the step of: During the molding process, the first molding speed of the molding structure on the substrate is monitored within a first time period; When the first forming speed is less than the first set forming speed, the first speed will be reduced to obtain the second speed. Correspondingly, the aerosol jetting device will use the second speed for printing.

10. The preparation method according to claim 9, characterized in that, It also includes the following steps: The second forming speed of the formed structure on the substrate was monitored during the next second time period. When the second forming speed is greater than or equal to the second set forming speed, the second speed is maintained to continue printing. And / or, the method further includes the step of: During the next second time period, continue to monitor the second forming speed of the already formed structure on the substrate during the first time period; If the second forming speed is less than the second set forming speed, it is recommended that the user update the slicing results again. The slicing results include: the number of slice layers and the thickness of the slice layers.

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