Electrification-ionization double-layer structure epidermal electrode and preparation method and application thereof

Abstract

The invention relates to the technical field of epidermal signal acquisition equipment, and provides an ionization-electricity double-layer structure epidermal electrode and a preparation method and application thereof.The ionization-electricity double-layer structure epidermal electrode comprises an electronic conducting layer, the electronic conducting layer is provided with a concave-convex first surface, an ion conducting layer is arranged on the first surface of the electronic conducting layer, and the ion conducting layer is arranged on the second surface of the electronic conducting layer. And a concave-convex ionization-electricity interface is formed between the electron conducting layer and the ion conducting layer. According to the ionization-electricity double-layer structure skin electrode, the ionization-electricity coupling efficiency is improved, the interface impedance is reduced, then the baseline noise level of electrophysiological signals is reduced, and high-fidelity electrophysiological signal collection is achieved.

Description

Technical Field

[0001] The present application belongs to the technical field of epidermal signal acquisition equipment, and in particular, relates to an ion-electric double-layer structure epidermal electrode and a preparation method and application thereof. Background Art

[0002] Electrophysiological signals are important information that reflects the complex life phenomena of organisms. Obtaining high-fidelity electrophysiological signals is of great significance for clinical diagnosis, health testing, rehabilitation medicine, etc. Electrophysiological signals are the potential differences between different parts of the body due to the difference in ion concentrations inside and outside the cell membrane. Common electrophysiological signals include electrocardiogram, electroencephalogram, electromyography, etc. Using electrodes to convert the ion potential generated by biological activities into the electronic potential in the measurement system is the most common means of detecting electrophysiological signals. Among them, epidermal electrodes are widely used in the collection of various types of electrophysiological signals because they cause almost no damage to the human body during use.

[0003] However, electrophysiological signals are usually difficult to measure accurately due to their weak signal strength (microvolt to millivolt level), high impedance of the signal source, and complex interface phenomena between the organism and the electrode. Impedance is an important source of thermal noise. The relationship between thermal noise and impedance can be expressed as V noise 2 =4kTfZ, where k is the Boltzmann constant, T is temperature, f is bandwidth, and Z is impedance. Therefore, it is necessary to reduce the interface impedance between the electrode and the epidermis to improve the fidelity of the electrophysiological signal. Summary of the invention

[0004] The purpose of the present application is to provide an ion-electric double-layer structure epidermal electrode and its preparation method and application, aiming to solve the problem of poor fidelity of electrophysiological signals collected by existing epidermal electrodes.

[0005] In order to achieve the above application purpose, the technical solution adopted in this application is as follows:

[0006] In a first aspect, the present application provides an ion-electrode double-layer structure epidermal electrode, comprising an electron conductive layer, the electron conductive layer having a concave-convex first surface, an ion conductive layer being arranged on the first surface of the electron conductive layer, and a concave-convex ion-electrode interface being formed between the electron conductive layer and the ion conductive layer.

[0007] In a second aspect, the present application provides a method for preparing an ion-electric double-layer structure epidermal electrode, comprising the following steps:

[0008] Providing a mold, wherein the mold has a surface with a concave-convex structure;

[0009] coating an electronically conductive polymer solution on the surface of the concavo-convex structure of the mold, and obtaining the electronically conductive layer having the first surface through drying;

[0010] The ion conductive layer pre-curing solution is coated on the first surface of the electronic conductive layer, and the ion conductive layer is obtained by curing, thereby obtaining an ion-electrode double-layer structure epidermal electrode with a concave-convex ion-electrode interface.

[0011] In a third aspect, the present application provides an application of an ion-electric double-layer structure epidermal electrode, wherein the ion-electric double-layer structure epidermal electrode is used to collect electrophysiological signals of the epidermis.

[0012] The ion-electrode double-layer structure epidermal electrode provided in the first aspect of the present application adopts a double-layer structure of an electronic conductive layer and an ion conductive layer, and realizes the integration of the electronic conductive layer and the ion conductive layer by forming a concave-convex ion-electrode interface between the electronic conductive layer and the ion conductive layer, which can increase the physical anchoring effect between the electronic conductive layer and the ion conductive layer, thereby improving the bonding strength between them and reducing the possibility of interlayer separation; in addition, the ion-electrode interface area is increased, the ion-electrode coupling efficiency is improved, and the interface impedance is reduced, thereby improving the conversion efficiency of ion signals to electronic signals near the interface between the ion conductive layer and the electronic conductive layer, reducing the baseline noise level of the electrophysiological signal, and realizing the acquisition of high-fidelity electrophysiological signals.

[0013] The preparation method of the ion-electric double-layer structure epidermal electrode provided in the second aspect of the present application is by coating an electronic conductive polymer solution on a mold having a concave-convex structure on the surface, and forming a concave-convex first surface while the electronic conductive polymer solution forms an electronic conductive layer through drying. Then, the ion conductive layer pre-curing solution is coated on the first surface of the electronic conductive layer, and while the ion conductive layer is formed by curing, a concave-convex ion-electric interface is formed between the electronic conductive layer and the ion conductive layer, so that the electronic conductive layer and the ion conductive layer are integrated to obtain an ion-electric double-layer structure epidermal electrode. In addition, the ion-electric interface area is also improved, the ion-electric coupling efficiency is improved, the interface impedance is reduced, and then the conversion efficiency of the ion signal-electronic signal near the interface between the ion conductive layer and the electronic conductive layer is improved, the baseline noise level of the electrophysiological signal is reduced, and the collection of high-fidelity electrophysiological signals is achieved.

[0014] The application of the ion-electric double-layer structure epidermal electrode provided in the third aspect of the present application can be used to collect electrophysiological signals of the epidermis. Since it has an electronic conductive layer and an ion conductive layer with high electrical conductivity, it provides a higher carrier concentration for the ion-electric double-layer structure epidermal electrode to conduct electrophysiological signals, and provides a material basis for converting the electrophysiological signals in the form of ions of the human body into electronic signals of the circuit. In addition, due to the concave-convex ion-electric interface, the interface impedance and baseline noise level of the ion-electric double-layer structure epidermal electrode are greatly reduced, thereby realizing the collection of high-fidelity electrophysiological signals. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings required for use in the embodiments or prior art descriptions are briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application, and for ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0016] Figure 1 This is a schematic diagram of the structure of an ion-electric double-layer epidermal electrode provided in an embodiment of the present application;

[0017] Figure 2 It is a schematic flow chart of a method for preparing an ion-electric double-layer structure epidermal electrode provided in an embodiment of the present application;

[0018] Figure 3 This is a comparison diagram of the interface impedance of the ion-electric double-layer structure epidermal electrode prepared in Example 1 of the present application and the commercial Ag / AgCl electrode.

[0019] Among them, the reference numerals in the figure are:

[0020] 1-Electronic conductive layer; 2-Ionic conductive layer; 3-Ion-electron interface. DETAILED DESCRIPTION

[0021] In order to make the technical problems, technical solutions and beneficial effects to be solved by the present application more clearly understood, the present application is further described in detail below in conjunction with the embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application.

[0022] In this application, the term "and / or" describes the association relationship of associated objects, indicating that there may be three relationships. For example, A and / or B can mean: A exists alone, A and B exist at the same time, and B exists alone. A and B can be singular or plural. The character " / " generally indicates that the associated objects are in an "or" relationship.

[0023] In this application, "at least one" means one or more, and "plurality" means two or more. "At least one of the following" or similar expressions refers to any combination of these items, including any combination of single items or plural items. For example, "at least one of a, b, or c", or "at least one of a, b, and c" can all mean: a, b, c, ab (i.e., a and b), ac, bc, or abc, where a, b, c can be single or multiple, respectively.

[0024] It should be understood that in the various embodiments of the present application, the size of the serial numbers of the above-mentioned processes does not mean the order of execution, some or all of the steps can be executed in parallel or sequentially, and the execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of the present application.

[0025] The terms used in the embodiments of the present application are only for the purpose of describing specific embodiments, and are not intended to limit the present application. The singular forms "a", "said" and "the" used in the embodiments of the present application and the appended claims are also intended to include plural forms, unless the context clearly indicates other meanings.

[0026] The weight of the relevant components mentioned in the embodiment description of the present application can not only refer to the specific content of each component, but also represent the proportional relationship between the weights of the components. Therefore, as long as the content of the relevant components is proportionally enlarged or reduced according to the embodiment description of the present application, it is within the scope disclosed in the embodiment description of the present application. Specifically, the mass described in the embodiment description of the present application can be a mass unit known in the chemical industry such as μg, mg, g, kg, etc.

[0027] The terms "first" and "second" are used only for descriptive purposes to distinguish objects such as substances from each other, and should not be understood as indicating or implying relative importance or implicitly indicating the number of indicated technical features. For example, without departing from the scope of the embodiments of the present application, the first XX may also be referred to as the second XX, and similarly, the second XX may also be referred to as the first XX. Thus, features defined as "first" and "second" may explicitly or implicitly include one or more of the features.

[0028] Epidermal electrodes refer to electrodes used on the surface of the skin of an organism, and can be used to test the electrophysiological signals of the organism. The organism can be various animals (such as mammals) or humans.

[0029] A first aspect of an embodiment of the present application provides an ion-electrode double-layer structure epidermal electrode, comprising an electronic conductive layer 1, wherein the electronic conductive layer 1 has a concave-convex first surface, an ion conductive layer 2 is provided on the first surface of the electronic conductive layer 1, and a concave-convex ion-electrode interface 3 is formed between the electronic conductive layer 1 and the ion conductive layer 2.

[0030] The above-mentioned concavo-convex first surface is a surface with a microscopic uneven or textured structure, so that a concavo-convex ion-electron interface 3 is formed at the junction of the electronic conductive layer 1 and the ion conductive layer 2 .

[0031] The ion-electrode double-layer structure epidermal electrode provided in the embodiment of the present application adopts a double-layer structure of an electronic conductive layer 1 and an ion conductive layer 2, and realizes the integration of the electronic conductive layer 1 and the ion conductive layer 2 by forming a concave-convex ion-electrode interface 3 between the electronic conductive layer 1 and the ion conductive layer 2, which can increase the physical anchoring effect between the electronic conductive layer 1 and the ion conductive layer 2, thereby improving the bonding strength between them and reducing the possibility of interlayer separation; in addition, the area of ​​the ion-electrode interface 3 is increased, the ion-electrode coupling efficiency is improved, and the interface impedance is reduced, thereby improving the conversion efficiency of ion signals-electronic signals near the interface between the ion conductive layer 2 and the electronic conductive layer 1, reducing the baseline noise level of the electrophysiological signal, and realizing the collection of high-fidelity electrophysiological signals.

[0032] In some embodiments, the first surface may be formed by a roughening treatment. Here, "roughening treatment" refers to a process of creating or increasing microscopic unevenness or texture on the surface of a material.

[0033] In some embodiments, the Ra value of the first surface is greater than 0.15 μm. The Ra value of the first surface refers to the arithmetic mean roughness of the first surface, which refers to the average height of the protrusions and depressions on the first surface measured within a certain length range. The larger the Ra value, the rougher the surface; the smaller the Ra value, the smoother the surface.

[0034] When the Ra value of the first surface is greater than 0.15 μm, it can be considered that the first surface at this time is rougher than the surface of the conventional electronic conductive layer. The use of the roughened first surface can form a roughened ion-electrode interface 3 between the electronic conductive layer 1 and the ion conductive layer 2, thereby increasing the area of ​​the ion-electrode interface 3, and further improving the conversion efficiency of ion signal-electronic signal near the interface between the ion conductive layer 2 and the electronic conductive layer 1.

[0035] In some embodiments, the total thickness of the electronic conductive layer 1 and the ion conductive layer 2 is 0.1 mm to 5 mm.

[0036] By controlling the total thickness of the electronic conductive layer 1 and the ion conductive layer 2, the signal transmission efficiency of the epidermal electrode can be ensured while ensuring that the epidermal electrode is not too thick to affect the conformality with the skin surface, so as to avoid possible impact on the accuracy of signal acquisition. In addition, if the electronic conductive layer 1 and the ion conductive layer 2 are too thick, the material cost will increase, and if the electronic conductive layer 1 and the ion conductive layer 2 are too thin, the difficulty of the epidermal electrode preparation process will be greatly increased, and the epidermal electrode will be prone to cohesive failure, which will affect the durability and reliability of the epidermal electrode.

[0037] In some embodiments, raw materials for preparing the electronic conductive layer 1 include a polymer substrate and a conductive material.

[0038] In the formulation system of the electronic conductive layer 1 , the conductive material provides conductivity, and the polymer matrix provides dispersion, mechanical support and elasticity, thereby obtaining a flexible electronic conductive layer 1 .

[0039] In some embodiments, the mass ratio of the conductive material to the water-soluble polymer substrate is (0.2-5): 10. Specifically, the mass ratio of the conductive material to the water-soluble polymer substrate can be 0.2:10, 0.5:10, 0.75:10, 1:10, 1.25:10, 2:10, 5:10, or any value between the above adjacent values.

[0040] In some embodiments, the conductive material includes poly(3,4-ethylenedioxythiophene)-polystyrene sulfonic acid.

[0041] Poly(3,4-ethylenedioxythiophene)-polystyrene sulfonic acid (PEDOT:PSS) is a conductive polymer, in which poly(3,4-ethylenedioxythiophene) (PEDOT) is a conductive polymer with a conjugated structure, has high conductivity and good chemical stability, and polystyrene sulfonate (PSS) is a water-soluble polymer. The combination of the two can produce PEDOT:PSS with good water dispersibility.

[0042] In some embodiments, the polymer substrate includes at least one of polyvinyl alcohol and styrene-butadiene rubber.

[0043] Polyvinyl alcohol (PVA) and styrene butadiene rubber (SBR) can provide good mechanical strength and flexibility.

[0044] In some embodiments, the raw materials for preparing the electronic conductive layer 1 include PEDOT:PSS, PVA and SBR, wherein the mass ratio of PEDOT:PSS, PVA and SBR is (0.75-1.25):1.5:8.5. Specifically, the mass ratio of PEDOT:PSS, PVA and SBR can be 0.75:1.5:8.5, 1:1.5:8.5, 1.25:1.5:8.5, or any value between the above adjacent values.

[0045] In the formula system of the electronic conductive layer 1, the conductive material and the polymer matrix in a specific mass ratio can ensure the high conductivity and good conformality of the electronic conductive layer 1, an appropriate amount of polyvinyl alcohol provides mechanical support and dispersion to form a stable conductive network, ensuring the continuity and stability of the conductive path, and an appropriate amount of styrene-butadiene rubber ensures the elasticity of the electronic conductive layer 1.

[0046] In some embodiments, the raw materials for preparing the ion conductive layer 2 include the following components in parts by weight:

[0047] 1 to 20 parts of 3-methacryloyl dopamine;

[0048] 0.5 to 10 parts of photoinitiator;

[0049] 80-120 parts of acrylic acid;

[0050] 20 to 200 parts of deep eutectic solvent.

[0051] In the formula system of the ion conductive layer 2, the photoinitiator initiates the copolymerization of acrylic acid and 3-methacryloyl dopamine by absorbing light energy to form a polymer network, thereby providing adhesion and stability of the ion conductive layer 2. The deep eutectic solvent is a low melting point mixture formed by two or more components through hydrogen bonding. The addition of the deep eutectic solvent provides the conductivity and high moisture retention of the ion conductive layer 2, thereby obtaining an ion conductive layer 2 with high ion concentration, low volatility and high ion conductivity.

[0052] In some embodiments, the photoinitiator includes at least one of α-ketoglutaric acid, photoinitiator 127, photoinitiator 2959 and benzophenone. Among them, the chemical composition of photoinitiator 127 is 1,1'-(methylenedi-4,1-phenylene)bis[2-hydroxy-2-methyl-1-propanone], and the chemical composition of photoinitiator 2959 is 2-hydroxy-4'-(2-hydroxyethoxy)-2-methylpropiophenone. Both are new high-efficiency non-yellowing ultraviolet photoinitiators that can initiate the polymerization of monomers containing unsaturated double bonds to form polymers. In the formulation system of the ion conductive layer of the embodiment of the present application, the photoinitiator generates primary free radicals under the triggering of ultraviolet light, and the primary free radicals initiate monomers (3-methacryloyl dopamine and acrylic acid) to generate monomer free radicals. The monomer free radicals and monomers continue to react to achieve chain growth, and finally an ion conductive layer mixed with a polymer and a deep eutectic solvent is obtained.

[0053] In some embodiments, the deep eutectic solvent includes a hydrogen bond acceptor and a hydrogen bond donor in a molar ratio of 1:(1-3). The hydrogen bond acceptor and the hydrogen bond donor form a deep eutectic solvent through hydrogen bonding. Specifically, the molar ratio of the hydrogen bond acceptor to the hydrogen bond donor can be 1:1, 1:1.2, 1:1.5, 1:1.8, 1:2, 1:2.3, 1:2.5, 1:3, or any value between the above adjacent values.

[0054] In some embodiments, the hydrogen bond donor includes at least one of ethylene glycol, glycerol, urea and diethylene glycol. All of the above substances can act as hydrogen bond donors in the formulation system and form a deep eutectic solvent with a hydrogen bond acceptor.

[0055] In some embodiments, the hydrogen bond acceptor includes at least one of choline chloride, tetrabutylammonium chloride, tetrabutylammonium bromide and tetrabutylammonium iodide. All of the above substances can form a deep eutectic solvent with the hydrogen bond donor as a hydrogen bond acceptor. And as an ion conductive medium, it can form an ion channel in the polymer to enhance the ion conductivity of the ion conductive layer 2.

[0056] A second aspect of the present application provides a method for preparing an ion-electric double-layer structure epidermal electrode, comprising the following steps:

[0057] Providing a mold, wherein the mold has a surface with a concave-convex structure;

[0058] The electronic conductive polymer solution is coated on the surface of the concavo-convex structure of the mold, and after drying, an electronic conductive layer 1 having a first surface is obtained;

[0059] The ion conductive layer pre-curing solution is coated on the first surface of the electronic conductive layer 1, and the ion conductive layer 2 is obtained after curing, thereby obtaining an ion-electrode double-layer structure epidermal electrode.

[0060] The preparation method of the ion-electric double-layer structure epidermal electrode provided in the embodiment of the present application is to coat an electronic conductive polymer solution on a mold having a concave-convex structure on the surface, and form a concave-convex first surface while the electronic conductive polymer solution forms an electronic conductive layer 1 through drying. Then, the ion conductive layer pre-curing solution is coated on the first surface of the electronic conductive layer 1, and while in-situ curing forms the ion conductive layer 2, a concave-convex ion-electric interface 3 is formed between the electronic conductive layer 1 and the ion conductive layer 2, so that the electronic conductive layer 1 and the ion conductive layer 2 are stably integrated together to obtain an ion-electric double-layer structure epidermal electrode. In addition, the ion-electric interface area is also improved, the ion-electric coupling efficiency is improved, the interface impedance is reduced, and then the conversion efficiency of the ion signal-electronic signal near the interface between the ion conductive layer 2 and the electronic conductive layer 1 is improved, the baseline noise level of the electrophysiological signal is reduced, and the collection of high-fidelity electrophysiological signals is achieved.

[0061] In some embodiments, the thickness of the liquid film of the electronic conductive polymer solution is 20 μm to 5000 μm. Specifically, the thickness of the liquid film of the electronic conductive polymer solution can be 20 μm, 50 μm, 100 μm, 200 μm, 500 μm, 1000 μm, 2000 μm or 5000 μm, or any value between the above adjacent values. The mass concentration of the conductive material in the electronic conductive polymer solution is 2 wt% to 50 wt%.

[0062] In some embodiments, the liquid film thickness of the ion conductive layer pre-curing solution is 25 μm to 5000 μm. Specifically, the liquid film thickness of the ion conductive layer pre-curing solution can be 25 μm, 75 μm, 150 μm, 500 μm, 1000 μm, 2000 μm or 5000 μm, or any value between the above adjacent values.

[0063] By controlling the liquid film thickness of the electronic conductive polymer solution, the liquid film thickness of the ion conductive layer pre-curing solution and the solid content in the electronic conductive polymer solution, the thickness of the electronic conductive layer 1 and the ion conductive layer 2 can be controlled. The thickness of the electronic conductive layer obtained by control is equivalent to the thickness of the ion conductive layer, ensuring the balance of the transmission of electrons and ions in the ion-electrode double-layer structure epidermal electrode, thereby ensuring the efficiency of signal collection.

[0064] In some embodiments, the preparation of the electronically conductive polymer solution includes the following steps: performing a first mixing process on a conductive material and a polymer substrate.

[0065] In some embodiments, the preparation of the ion conductive layer pre-curing solution includes the following steps: performing a second mixing process on 3-methacryloyldopamine, a photoinitiator, acrylic acid, and a deep eutectic solvent.

[0066] In some embodiments, the deep eutectic solvent comprises the following preparation step: mixing a hydrogen bond acceptor and a hydrogen bond donor under heating conditions to obtain a deep eutectic solvent.

[0067] In some embodiments, the heating temperature is 78°C to 95°C, and the heating time is 1.5 to 2.5 hours. Specifically, the heating temperature can be 78°C, 80°C, 82°C, 85°C, 90°C and 95°C, or any value between the above adjacent values. The heating time can be 1.5 hours, 1.8 hours, 2 hours and 2.5 hours, or any value between the above adjacent values.

[0068] In some embodiments, the preparation of the mold includes the following steps: coating the elastomeric material solution on sandpaper with a mesh size of 1000 to 20000, curing the solution, and then demoulding the solution to obtain the mold.

[0069] Specifically, the elastomer material includes SYLGARD TM 184. At least one of Ecoflex and Dragon skin. SYLGARD TM184 is a two-component room temperature curing silicone rubber, which is mainly composed of polydimethylsiloxane and curing agent. Ecoflex and Dragon skin are both commonly used silicone materials. The above substances can be used to prepare a mold. When preparing the mold, the elastomer material is first prepared into a solution and then coated on sandpaper for curing. After removing the sandpaper, a surface with a rough microstructure can be obtained on the mold.

[0070] In some embodiments, the mesh number of the sandpaper can be 1000 mesh, 2000 mesh, 5000 mesh, 6000 mesh, 7000 mesh, 10000 mesh, 11000 mesh, 12000 mesh, 15000 mesh, 18000 mesh and 20000 mesh, or any value between the above adjacent values.

[0071] In some embodiments, the drying step includes: natural drying for 3 to 12 hours.

[0072] In some embodiments, the curing step includes: UV curing for 3 to 10 minutes.

[0073] See also Figure 2 , Figure 2 A method for preparing an ion-electric double-layer structure epidermal electrode provided in an embodiment of the present application, as shown in the figure, comprises the following steps:

[0074] S10, providing a mold, wherein the mold has a surface with a concave-convex structure;

[0075] S20, performing a first mixing process on the conductive material and the polymer substrate to obtain an electronic conductive polymer solution;

[0076] S30, coating the electronic conductive polymer solution on the surface of the concavo-convex structure of the mold, and obtaining an electronic conductive layer having a first surface after drying;

[0077] S40, performing a second mixing process on 3-methacryloyl dopamine, a photoinitiator, acrylic acid and a deep eutectic solvent to obtain an ion conductive layer pre-curing solution;

[0078] S50, coating the ion conductive layer pre-curing solution on the first surface of the electronic conductive layer, and obtaining the ion conductive layer through curing to obtain an ion-electrode double-layer structure epidermal electrode.

[0079] A third aspect of an embodiment of the present application provides an application of an ion-electric double-layer structure epidermal electrode, which is used to collect electrophysiological signals of the epidermis.

[0080] The ion-electrode double-layer structure epidermal electrode provided in the embodiment of the present application can be used to collect electrophysiological signals of the epidermis. Since it has an electronic conductive layer and an ion conductive layer with high electrical conductivity, it provides a higher carrier concentration for the epidermal electrode to conduct electrophysiological signals, and provides a material basis for converting the electrophysiological signals in the form of ions of the human body into electronic signals of the circuit. In addition, due to the concave-convex ion-electrode interface, the interface impedance and baseline noise level of the epidermal electrode are greatly reduced, thereby realizing the collection of high-fidelity electrophysiological signals.

[0081] Specifically, the obtained ion-electric double-layer epidermal electrode is processed into the required area and shape using a laser cutting machine, and the metal wire is integrated on the electronic conductive layer using conductive silver paste. When in use, the ion conductive layer of the ion-electric double-layer epidermal electrode is adhered to the skin just above the muscle, and the metal wire is connected to an external electrical device to collect the electromyographic signal of the epidermis. When in use, multiple patches can be used, and the distance between adjacent patches is 1-2 cm.

[0082] The following describes the invention in conjunction with specific embodiments.

[0083] Example 1

[0084] An ion-electrode double-layer structure epidermal electrode, composed of a stacked electronic conductive layer and an ion conductive layer, the overall thickness of the epidermal electrode is about 0.5 mm. The electronic conductive layer has a concave-convex first surface, the Ra value of the first surface is 0.846 μm, and a concave-convex ion-electrode interface is formed between the electronic conductive layer and the ion conductive layer.

[0085] The electronic conductive polymer solution consists of an aqueous dispersion of PEDOT:PSS with a mass concentration of 1wt%, an aqueous PVA solution with a mass concentration of 10wt% and an aqueous SBR dispersion with a mass concentration of 50wt%, and the mass ratio of PEDOT:PSS, PVA and SBR is 1:1.5:8.5.

[0086] The ion conductive layer pre-curing liquid consists of 5 parts of 3-methacryloyl dopamine, 1 part of a photoinitiator (α-ketoglutaric acid), 100 parts of acrylic acid and 115 parts of a deep eutectic solvent (consisting of a hydrogen bond acceptor (choline chloride) and a hydrogen bond donor (ethylene glycol) in a molar ratio of 1:2).

[0087] The ion-electric double-layer structure epidermal electrode is prepared by the following preparation steps:

[0088] Making mold: SYLGARD TM The elastomeric material solution prepared by 184 is coated on 10000 mesh sandpaper, and the sandpaper is demoulded after curing to obtain a mold with a surface having a concave-convex structure.

[0089] Preparation of electronic conductive polymer solution: polyvinyl alcohol was dissolved in water at 80° C. to prepare a 10 wt % aqueous solution, and the PEDOT:PSS aqueous dispersion, PVA aqueous solution and SBR aqueous dispersion were shaken and mixed to form an electronic conductive polymer solution.

[0090] Preparation of electronic conductive layer: coating electronic conductive polymer solution on the surface of the concave-convex structure of the mold, the liquid film thickness of the electronic conductive polymer solution is 1 mm, and naturally drying in air for 12 hours to obtain an electronic conductive layer having a concave-convex first surface.

[0091] Preparation of ion conductive layer pre-curing liquid: first, choline chloride and ethylene glycol are mixed at 80° C. to form a deep eutectic solvent. Then, α-ketoglutaric acid, 3-methacryloyldopamine, acrylic acid and the deep eutectic solvent are shaken and mixed to form an ion conductive layer pre-curing liquid.

[0092] Preparation of an ion conductive layer and an ion-electric double-layer structure epidermal electrode: coating the ion conductive layer pre-curing liquid on the first surface of the electronic conductive layer, controlling the thickness of the electronic conductive layer and the ion conductive layer pre-curing liquid to be 0.5 mm in total using a silicone gasket and a glass plate, in-situ UV-curing the ion conductive layer pre-curing liquid for 5 minutes to form an ion conductive layer, and obtaining an ion-electric double-layer structure epidermal electrode.

[0093] Application of the ion-electric double-layer epidermal electrode: Using a laser cutting machine to cut a 1cm 2 The patch has a large sensing area and is used to be attached to the muscle to collect electromyographic signals.

[0094] Example 2

[0095] An ion-electrode double-layer structure epidermal electrode is different from Example 1 in that the mass ratio of PEDOT:PSS, PVA and SBR is 0.75:1.5:8.5. The rest is the same as Example 1.

[0096] Example 3

[0097] An ion-electrode double-layer structure epidermal electrode is different from Example 1 in that the mass ratio of PEDOT:PSS, PVA and SBR is 1.25:1.5:8.5. The rest is the same as Example 1.

[0098] Example 4

[0099] An ion-electrode double-layer structure epidermal electrode is different from Example 1 in that propylene glycol is used as a hydrogen bond donor in the deep eutectic solvent instead of ethylene glycol. The rest is the same as Example 1.

[0100] Example 5

[0101] An ion-electric double-layer structure epidermal electrode is different from Example 1 in that: in the ion conductive layer pre-curing liquid, photoinitiator 127 is used instead of α-ketoglutaric acid as the photoinitiator. The rest is the same as Example 1.

[0102] Example 6

[0103] An ion-electrode double-layer structure epidermal electrode, which differs from Example 1 in that: in the electronic conductive polymer solution, the aqueous dispersion of the conductive material is an aqueous dispersion of carbon nanotubes with a mass concentration of 16.2wt%, and the mass ratio of the conductive material to the polymer substrate is the same. The rest is the same as Example 1.

[0104] Performance Testing

[0105] 1. Test of the conductivity of the electronic conductive layer: The conductivity of the electronic conductive layer of the ion-electric double-layer structure epidermal electrodes prepared in Examples 1-6 was tested using a four-probe method. The test results are shown in Table 1.

[0106] 2. Test of the conductivity of the ion conductive layer: The conductivity of the ion conductive layer of the ion-electric double-layer structure epidermal electrode prepared in Examples 1-6 was measured using an electrochemical workstation using an AC impedance spectroscopy method. The test results are shown in Table 1.

[0107] Table 1 Conductivity test results

[0108]

[0109]

[0110] It can be seen from Table 1 that the ion-electrode double-layer structure epidermal electrode prepared by the embodiment of the present application has a high-conductivity electronic conductive layer and a high-conductivity ion conductive layer. Among them, the conductivity of the electronic conductive layer prepared by using the carbon nanotube solution as the conductive material is as high as 3.4S cm -1 The conductivity of the ion conductive layer in each embodiment can reach 0.06mS cm -1 This highly conductive electronic conductive layer and highly conductive ionic conductive layer provide a higher carrier concentration for the epidermal electrode to conduct electrophysiological signals, and provide a material basis for converting the body's electrophysiological signals in the form of ions into electronic signals of the circuit.

[0111] 3. Interface impedance test: The ion-electric double-layer structure epidermal electrode prepared in Example 1 was cut into a 1 cm 2 For the patch samples with large sensing area, two patches were placed just above the arm muscles, 2 cm apart, and the interface impedance was measured using an electrochemical workstation. The same test method was used to conduct a synchronous comparative test on commercial Ag / AgCl electrodes. The test results are shown in Figure 2. Figure 3 As shown. Figure 3It can be seen that the interface impedance of the epidermal electrode with the ion-electrode double-layer structure of Example 1 is one order of magnitude lower than the interface impedance of the commercial Ag / AgCl electrode, indicating that the embodiment of the present application uses the ion-electrode double-layer structure and roughens the interface between the electronic conductive layer and the ion conductive layer to improve the conversion efficiency of ion signals to electronic signals near the interface between the ion conductive layer and the electronic conductive layer, that is, to improve the ion-electrode coupling efficiency and reduce the interface impedance.

[0112] 4. Electromyographic signal test: Baseline noise test and signal-to-noise ratio test were performed on Examples 1 and 4-6, respectively. While performing the experiments on Examples 1 and 4-6, conventional molds with smooth surfaces were also used for simultaneous comparison experiments. The surface Ra value of the electronic conductive layer was 0.118 μm, and an epidermal electrode with an unroughened interface was obtained. Baseline noise test and signal-to-noise ratio test were performed on the epidermal electrode with an unroughened interface, respectively. In addition, currently commercially available Ag / AgCl electrodes were used for baseline noise test and signal-to-noise ratio test.

[0113] a. Baseline noise test: Cut the epidermal electrode into a 1cm 2 For the patch sample with the largest sensing area, two patches are attached just above the arm muscles, with a distance of 2 cm between the two patches. The resting signal is measured when the muscles are relaxed, and the baseline noise data is calculated. The calculation method of the baseline noise data is: take each sample value of the baseline segment signal, square each sample value, calculate the average value of all square values, and square the average value. The formula is as follows: The data results are shown in Table 2.

[0114] b. Signal-to-noise ratio test: Cut the epidermal electrode into a 1cm 2 For the patch sample with large sensing area, two patches are attached just above the arm muscle, with a distance of 2 cm between the two patches. The signals of muscle contraction and relaxation are measured. The muscle relaxation segment is selected as the noise data segment, and the muscle contraction segment is selected as the signal data segment. The signal-to-noise ratio data is calculated by calculating the root mean square value (RMS noise) of the baseline noise segment and the root mean square value (RMS signal) of the signal segment. The formula is: The data results are shown in Table 2.

[0115] Table 2 EMG signal test results

[0116]

[0117] Note: The rough interface in Table 2 has a Ra value greater than 0.15 μm.

[0118] As can be seen from Table 2, the embodiment of the present application can significantly reduce the baseline noise level of the epidermal electrode and significantly improve the signal-to-noise ratio of the epidermal electrode by roughening the interface of the electronic conductive layer and the ion conductive layer. Among them, the baseline noise level and signal-to-noise ratio of Examples 1 to 5 are significantly better than the baseline noise level and signal-to-noise ratio of commercial Ag / AgCl electrodes. Secondly, by comparing Example 1 with Example 6, it can be found that although Example 6 is significantly better than Example 1 in terms of the conductivity of the electronic conductive layer, from the perspective of electromyographic signal testing, Example 6 is less effective than Example 1 in reducing the baseline noise level. Therefore, from the perspective of comprehensive conductivity and electromyographic signal testing, under the premise of other consistent conditions, the comprehensive performance of the ion-electric double-layer structure epidermal electrode prepared by using PEDOT:PSS as a conductive material to prepare the electronic conductive layer and finally prepared is better.

[0119] The above description is only a preferred embodiment of the present application and is not intended to limit the present application. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present application should be included in the protection scope of the present application.

Claims

1. An ion-electric double-layer structure epidermal electrode, characterized in that: The invention comprises an electronic conductive layer, wherein the electronic conductive layer has a concavoconvex first surface, an ion conductive layer is arranged on the first surface of the electronic conductive layer, and a concavoconvex ion-electron interface is formed between the electronic conductive layer and the ion conductive layer.

2. The ion-electric double-layer structure epidermal electrode according to claim 1, characterized in that: The Ra value of the first surface is greater than 0.15 μm; and / or, The total thickness of the electronic conductive layer and the ion conductive layer is 0.1 mm to 5 mm.

3. The ion-electric double-layer structure epidermal electrode according to claim 1, characterized in that: The raw materials for preparing the electronic conductive layer include a polymer substrate and a conductive material.

4. The ion-electric double-layer structure epidermal electrode according to claim 3, characterized in that: The mass ratio of the conductive material to the polymer substrate is (0.2-5):10; and / or, The conductive material includes poly(3,4-ethylenedioxythiophene)-polystyrene sulfonic acid; and / or, The polymer substrate includes at least one of polyvinyl alcohol and styrene-butadiene rubber.

5. The ion-electric double-layer structure epidermal electrode according to any one of claims 1 to 4, characterized in that: The raw materials for preparing the ion conductive layer include the following components in parts by weight: 1 to 20 parts of 3-methacryloyl dopamine; 0.5 to 10 parts of photoinitiator; 80-120 parts of acrylic acid; 20 to 200 parts of deep eutectic solvent.

6. The ion-electric double-layer structure epidermal electrode according to claim 5, characterized in that: The photoinitiator comprises at least one of α-ketoglutaric acid, photoinitiator 127, photoinitiator 2959 and benzophenone; and / or, The deep eutectic solvent comprises a hydrogen bond acceptor and a hydrogen bond donor in a molar ratio of 1:(1-3).

7. A method for preparing an ion-electric double-layer structure epidermal electrode according to any one of claims 1 to 6, characterized in that: The following steps are involved: Providing a mold, wherein the mold has a surface with a concave-convex structure; coating an electronically conductive polymer solution on the surface of the concavo-convex structure of the mold, and obtaining the electronically conductive layer having the first surface through drying; The ion conductive layer pre-curing solution is coated on the first surface of the electronic conductive layer, and the ion conductive layer is obtained by curing, thereby obtaining an ion-electrode double-layer structure epidermal electrode with a concave-convex ion-electrode interface.

8. The preparation method according to claim 7, characterized in that: The preparation of the electronic conductive polymer solution comprises the following steps: subjecting the conductive material and the polymer substrate to a first mixing process; and / or; The preparation of the ion conductive layer pre-curing solution comprises the following steps: performing a second mixing process on 3-methacryloyl dopamine, a photoinitiator, acrylic acid and a deep eutectic solvent.

9. The preparation method according to claim 7 or 8, characterized in that: The preparation of the mold comprises the following steps: The elastomer material solution is coated on sandpaper with mesh size of 1000-20000, and then cured and demoulded to obtain the mold.

10. An application of the ion-electric double-layer structure epidermal electrode according to any one of claims 1 to 6, characterized in that: The application of the ion-electric double-layer structure epidermal electrode in collecting epidermal electrophysiological signals.

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