A double-loop conductive hydrogel brain-computer interface electrode structure and a preparation method and application thereof

Abstract

This invention relates to a dual-ring conductive hydrogel brain-computer interface electrode structure, its preparation method, and its application, relating to the interdisciplinary fields of flexible electronics, biosensing technology, and electrophysiological monitoring. The dual-ring conductive hydrogel brain-computer interface electrode structure includes an inner ring main conductive channel layer and an outer ring secondary dissipative channel layer arranged coaxially. The raw materials for preparing the inner ring main conductive channel layer include a hydrogel matrix A, electronically conductive components, ionicly conductive components, and functional nanoparticles. The raw materials for preparing the outer ring secondary dissipative channel layer include a hydrogel matrix B, polarized modified nanofiller electret, a coordination crosslinking agent, a hydrogen bonding enhancer, and a segment relaxation modulation component. The dual-ring conductive hydrogel brain-computer interface electrode structure provided by this invention achieves a response characteristic of "high dissipation of low-frequency mechanical noise - low interference in the target signal frequency band" through spatial partitioning design and synergistic inner and outer ring formulation design.

Description

Technical Field

[0001] This invention relates to the interdisciplinary field of flexible electronics, biosensing technology and electrophysiological monitoring, and in particular to a double-ring conductive hydrogel brain-computer interface electrode structure, its preparation method and application. Background Technology

[0002] Physiological signals, such as alpha waves (8-13 Hz) and beta waves (14-30 Hz) in electroencephalography (EEG), are the core information carriers for clinical disease diagnosis, neuroscience research, and intelligent medical interaction. Non-invasive signal acquisition technology is widely used due to its safety and convenience, but existing acquisition devices have three major technical bottlenecks that seriously restrict signal fidelity: (1) Lack of selective damping performance: human respiration (0.1-1 Hz), limb shaking (1-10 Hz) Dynamic mechanical noise (Hz) and other frequencies partially overlap with the target electrophysiological signal frequency band. Traditional electrodes (such as Ag / AgCl) rely on post-processing algorithms for filtering, which can easily lead to signal distortion or loss of key information. Ordinary conductive hydrogels are mostly designed for broadband damping. While dissipating noise, they will attenuate high-frequency electrophysiological signals and cannot achieve a selective response of "high dissipation in the noise frequency band and low interference in the signal frequency band". (2) Poor compatibility between nanofillers and the matrix interface: The dielectric ceramics, metal oxides and other nanofillers commonly used in existing damping hydrogels are prone to aggregation due to their high surface energy. They form weak interfacial interactions with the hydrogel matrix (such as polyvinylpyrrolidone (PVP), polyvinyl alcohol (PVA), methacrylic anhydride modified gelatin (GelMA)), resulting in damping performance fluctuations (tanδ coefficient of variation > 20%). Moreover, the type and intensity of the interfacial interaction are not specifically optimized, and it is impossible to accurately match the chain segment relaxation requirements of the target noise frequency band. (3) Contradictory relationship between conductivity and damping function: Enhancing damping performance often requires increasing crosslinking density or filler content, but this will lead to a decrease in hydrogel conductivity and an increase in interfacial impedance (> 5). kΩ), poor impedance matching with traditional signal amplification circuits; while simply pursuing high conductivity (such as increasing the content of conductive filler) will destroy the damping network, resulting in weakened noise dissipation ability, making it difficult to achieve the synergistic performance of "high conductivity-high damping-low interface impedance"; (4) Insufficient interface stability and reusability: Existing hydrogel electrodes may cause skin residue and stratum corneum damage due to excessive adhesion (>30 kPa), or fall off in dynamic scenarios due to insufficient adhesion (<15 kPa). After repeated use 20 times, the interface impedance fluctuates by more than 30%, which cannot meet the needs of continuous clinical monitoring (such as 72-hour sleep EEG).

[0003] To address these issues, existing technologies attempt to optimize the composition or structure of hydrogels, but a systematic solution has yet to be found: some solutions only regulate damping performance through a single dynamic bond, making it difficult to cover the entire frequency range of 0.1-10 Hz noise; some solutions neglect the modification of the nanofiller interface, resulting in poor damping stability; and some solutions fail to achieve functional partitioning of conductivity and damping, making it impossible to avoid signal attenuation.

[0004] Therefore, there is an urgent need to develop a conductive hydrogel electrode structure that achieves performance decoupling and synergistic optimization through structural functional partitioning, interface engineering regulation, and multi-mechanism synergy, so as to improve the fidelity and stability of electrophysiological signal acquisition in complex dynamic environments. Summary of the Invention

[0005] To address the aforementioned technical problems, this invention provides a dual-ring conductive hydrogel brain-computer interface electrode structure, its preparation method, and its application. Through spatial partitioning design, the conductive path and dissipation path are physically separated. Combined with the formulation design of the inner ring main conductive channel layer and the outer ring secondary dissipation channel layer, the response characteristics of "high dissipation of low-frequency mechanical noise and low interference of target signal frequency band" are synergistically achieved. It is suitable for dynamic high-fidelity acquisition of non-invasive electrophysiological signals such as EEG and can be integrated into terminal products such as brain-computer interfaces, wearable medical devices, and transcranial nerve modulation systems.

[0006] To achieve this objective, the present invention adopts the following technical solution: In a first aspect, the present invention provides a dual-ring conductive hydrogel brain-computer interface electrode structure, the dual-ring conductive hydrogel brain-computer interface electrode structure comprising an inner ring main conductive channel layer and an outer ring secondary dissipative channel layer arranged coaxially. The raw materials for preparing the inner ring main conductive channel layer include hydrogel matrix A, electronically conductive components, ionicly conductive components, and functional nanoparticles. The raw materials for preparing the outer ring secondary dissipation channel layer include hydrogel matrix B, polarized modified nanofiller electret, coordination crosslinking agent, hydrogen bond enhancer, and segment relaxation regulating component.

[0007] The dual-ring conductive hydrogel brain-computer interface electrode structure provided by this invention achieves physical separation of conductive and dissipative paths through spatial partitioning design. Combined with the formulation design of the inner ring main conductive channel layer and the outer ring secondary dissipative channel layer, it synergistically achieves the response characteristics of "high dissipation of low-frequency mechanical noise and low interference of target signal frequency band". It suppresses motion artifacts from the source, reduces dependence on back-end signal processing algorithms, and avoids mutual interference between conductive and damping networks. It achieves a synergistic unity of high conductivity, low interface impedance and high damping performance, while also having frequency-selective damping and signal protection functions.

[0008] Preferably, the raw materials for preparing the inner ring main conductive channel layer further include solvent A.

[0009] Preferably, the raw materials for preparing the inner ring main conductive channel layer include, by mass percentage, 11-19 wt% hydrogel matrix A, 1.1-3.5 wt% electronically conductive component, 0.3-0.8 wt% ionicly conductive component, 0.5-2 wt% functional nanoparticles, and 74.7-87.1 wt% solvent A.

[0010] Among these, 11-19 wt% can be, for example, 11 wt%, 12 wt%, 13 wt%, 14 wt%, 15 wt%, 16 wt%, 17 wt%, 18 wt%, or 19 wt%, etc.; 1.1-3.5 wt% can be, for example, 1.1 wt%, 1.5 wt%, 2 wt%, 2.5 wt%, 3 wt%, or 3.5 wt%, etc.; 0.3-0.8 wt% can be, for example, 0.3 wt%, 0.4 wt%, 0.5 wt%, 0.6 wt%, 0.7 wt%, or 0.8 wt%, etc.; 0.5-2 wt% can be, for example, 0.5 wt%, 0.6 wt%, 0.8 wt%, 1 wt%, 1.2 wt%, 1.4 wt%, 1.5 wt%, 1.6 wt%, 1.8 wt%, or 2 wt%, etc.; 74.7-87.1 wt% can be, for example, 74.7 wt%. wt%, 75 wt%, 76 wt%, 78wt%, 80 wt%, 82 wt%, 84 wt%, 85 wt%, 86 wt%, 87 wt% or 87.1 wt%, etc.

[0011] Preferably, the hydrogel matrix A includes PVA and PVP.

[0012] Preferably, the hydrogel matrix A further includes gelatin and / or sodium alginate hydrogel.

[0013] Preferably, the hydrogel matrix A is a combination of PVA and PVP.

[0014] Preferably, based on the mass percentage of the raw materials used to prepare the inner ring main conductive channel layer being 100%, the raw materials used to prepare the inner ring main conductive channel layer contain 8-12 wt% PVA, for example, 8 wt%, 8.5 wt%, 9 wt%, 9.5 wt%, 10 wt%, 10.5 wt%, 11 wt%, 11.5 wt%, or 12 wt%, etc.

[0015] Preferably, based on the mass percentage of the raw materials used to prepare the inner ring main conductive channel layer being 100%, the raw materials used to prepare the inner ring main conductive channel layer contain 3-7 wt% PVP, for example, 3 wt%, 3.5 wt%, 4 wt%, 4.5 wt%, 5 wt%, 5.5 wt%, 6 wt%, 6.5 wt%, or 7 wt%, etc.

[0016] Preferably, the electronically conductive component includes electronically conductive fillers and electronically conductive polymers.

[0017] Preferably, based on the mass percentage of the raw materials used to prepare the inner ring main conductive channel layer being 100%, the raw materials used to prepare the inner ring main conductive channel layer contain 1-3 wt% electronic conductive filler, for example, 1 wt%, 1.5 wt%, 2 wt%, 2.5 wt%, or 3 wt%.

[0018] Preferably, based on the mass percentage of the raw materials used to prepare the inner ring main conductive channel layer being 100%, the raw materials used to prepare the inner ring main conductive channel layer contain 0.1-0.5 wt% of an electronically conductive polymer, for example, 0.1 wt%, 0.2 wt%, 0.3 wt%, 0.4 wt%, or 0.5 wt%.

[0019] Preferably, the electronically conductive filler comprises any one or a combination of at least two of silver nanowires, carbon nanotubes, graphene, carbon dots, silver nanoparticles, or conductive carbon black.

[0020] Preferably, the electronically conductive filler is silver nanowire.

[0021] Preferably, the diameter of the silver nanowire is 50-100 nm, for example, it can be 50 nm, 60 nm, 70 nm, 80 nm, 90 nm or 100 nm.

[0022] Preferably, the aspect ratio of the silver nanowire is 1:(50-100), for example, it can be 1:50, 1:60, 1:70, 1:80, 1:90 or 1:100, etc.

[0023] Preferably, the electronically conductive polymer comprises any one or a combination of at least two of poly(3,4-ethylenedioxythiophene), polystyrene sulfonate, polyaniline, polypyrrole, or polythiophene derivatives.

[0024] Preferably, the electronically conductive polymer is poly(3,4-ethylenedioxythiophene):polystyrene sulfonate.

[0025] Preferably, the ionic conductive component comprises an ionic liquid.

[0026] Preferably, the ionic liquid includes any one or a combination of at least two of imidazole ionic liquids, pyridine ionic liquids, quaternary ammonium salt ionic liquids, or lithium salt electrolytes.

[0027] Preferably, the imidazole ionic liquid comprises 1-butyl-3-methylimidazolium tetrafluoroborate.

[0028] Preferably, the functional nanoparticles include metal oxide nanoparticles.

[0029] Preferably, the metal oxide nanoparticles include any one or a combination of at least two of zinc oxide, titanium dioxide, iron tetroxide, silicon dioxide, aluminum oxide, cerium dioxide, or metal-organic framework materials.

[0030] Preferably, the metal oxide nanoparticles are zinc oxide.

[0031] Preferably, the particle size distribution range of the metal oxide nanoparticles is 30-100 nm, for example, it can be 30 nm, 40 nm, 50 nm, 60 nm, 70 nm, 80 nm, 90 nm or 100 nm.

[0032] Preferably, solvent A comprises water.

[0033] Preferably, the conductivity of the inner ring main conductive channel layer is 0.5-1.5 S / m, for example, it can be 0.5 S / m, 0.6 S / m, 0.8 S / m, 1 S / m, 1.2 S / m, 1.4 S / m or 1.5 S / m, etc.

[0034] The conductivity was tested using an ST2258C four-probe conductivity meter in accordance with ASTM F84-02 standard.

[0035] Preferably, the raw materials for preparing the inner ring main conductive channel layer include, by mass percentage, 8-12 wt% PVA, 3-7 wt% PVP, 1-3 wt% electronically conductive filler, 0.1-0.5 wt% electronically conductive polymer, 0.3-0.8 wt% ionicly conductive component, 0.5-2 wt% functional nanoparticles, and 74.7-87.1 wt% solvent A.

[0036] Specifically, 8-12 wt% can be, for example, 8 wt%, 8.5 wt%, 9 wt%, 9.5 wt%, 10 wt%, 10.5 wt%, 11 wt%, 11.5 wt%, or 12 wt%, etc.; 3-7 wt% can be, for example, 3 wt%, 3.5 wt%, 4 wt%, 4.5 wt%, 5 wt%, 5.5 wt%, 6 wt%, 6.5 wt%, or 7 wt%, etc.; 1-3 wt% can be, for example, 1 wt%, 1.5 wt%, 2 wt%, 2.5 wt%, or 3 wt%, etc.; 0.1-0.5 wt% can be, for example, 0.1 wt%, 0.2 wt%, 0.3 wt%, 0.4 wt%, or 0.5 wt%, etc.; 0.3-0.8 wt% can be, for example, 0.3 wt%, 0.4 wt%, 0.5 wt%, 0.6 wt%, 0.7 wt%, or 0.8 wt%, etc. wt% etc.; 0.5-2 wt% can be, for example, 0.5 wt%, 0.6 wt%, 0.8 wt%, 1 wt%, 1.2 wt%, 1.4 wt%, 1.5 wt%, 1.6 wt%, 1.8 wt% or 2 wt% etc.; 74.7-87.1 wt% can be, for example, 74.7 wt%, 75 wt%, 76 wt%, 78 wt%, 80 wt%, 82 wt%, 84 wt%, 85 wt%, 86 wt%, 87 wt% or 87.1 wt% etc.

[0037] The inner ring main conductive channel layer provided by this invention combines electronic conductive components, ionic conductive components and functional nanoparticles. The electronic conductive components form electronic conductive pathways, the ionic conductive components provide ionic conductive pathways, and the functional nanoparticles are used to optimize the interfacial charge distribution and improve the stability of the system, together constructing an "ionic-electronic hybrid conductive network".

[0038] Preferably, the raw materials for preparing the outer ring secondary dissipation channel layer also include solvent B.

[0039] Preferably, the raw materials for preparing the outer ring secondary dissipative channel layer include, by mass percentage, 10-18 wt% hydrogel matrix B, 1-5 wt% polarized modified nanofiller electret, 0.1-0.3 wt% coordination crosslinking agent, 0.5-1 wt% hydrogen bond enhancer, 5-8 wt% segment relaxation regulating component, and 67.7-83.4 wt% solvent B.

[0040] Among them, 10-18 wt% can be, for example, 10 wt%, 11 wt%, 12 wt%, 13 wt%, 14 wt%, 15 wt%, 16 wt%, 17 wt%, or 18 wt%, etc.; 1-5 wt% can be, for example, 1 wt%, 1.5 wt%, 2 wt%, 2.5 wt%, 3 wt%, 3.5 wt%, 4 wt%, 4.5 wt%, or 5 wt%, etc.; 0.1-0.3 wt% can be, for example, 0.1 wt%, 0.15 wt%, 0.2 wt%, 0.25 wt%, or 0.3 wt%, etc.; 0.5-1 wt% can be, for example, 0.5 wt%, 0.6 wt%, 0.7 wt%, 0.8 wt%, 0.9 wt%, or 1 wt%, etc.; 5-8 wt% can be, for example, 5 wt%, 5.5 wt%, 6 wt%, 6.5 wt%, 7 wt%, 7.5 wt%, or 8 wt%, etc. wt% etc.; 67.7-83.4 wt% for example, could be 67.7 wt%, 68 wt%, 69 wt%, 80 wt%, 81 wt%, 82 wt%, 83 wt% or 83.4 wt%, etc.

[0041] Preferably, the hydrogel matrix B comprises PVA and GelMA.

[0042] Preferably, the hydrogel matrix B further includes any one or a combination of at least two of silk fibroin, sodium alginate, gelatin, or hyaluronic acid.

[0043] Preferably, the hydrogel matrix B is a combination of PVA and GelMA.

[0044] In this invention, the hydrogel matrix B in the outer ring dissipation channel layer is a combination of PVA and GelMA. The side chains of GelMA (methacrylamide gelatin) are rich in carboxyl and amide active sites, which can coordinate with the coordination crosslinking agent. Under medium-frequency deformation under external force, the coordination bonds can be reversibly broken and recombined to achieve medium-frequency energy dissipation. The PVA (polyvinyl alcohol) main chain is densely covered with a large number of hydroxyl groups. The hydroxyl groups form dense intermolecular hydrogen bonds with the hydrogen bond enhancer. The hydrogen bond energy is low, corresponding to repeated dissociation and association under low-frequency vibration of 0.1~10 Hz, which achieves low-frequency mechanical noise dissipation. Silk fibroin, sodium alginate, gelatin and hyaluronic acid can be selected as auxiliary substrates: the carboxyl groups of sodium alginate can participate in coordination in a small amount; the hydroxyl groups of silk fibroin and hyaluronic acid can help generate hydrogen bonds and finely adjust the damping range.

[0045] Preferably, the degree of methacrylation of the GelMA is 60-80%, for example, it can be 60%, 65%, 70%, 75% or 80%, etc.

[0046] Preferably, based on the mass percentage of the raw materials used to prepare the outer ring secondary dissipation channel layer being 100%, the raw materials used to prepare the outer ring secondary dissipation channel layer contain 5-8 wt% PVA, for example, 5 wt%, 5.5 wt%, 6 wt%, 6.5 wt%, 7 wt%, 7.5 wt%, or 8 wt%, etc.

[0047] Preferably, based on the mass percentage of the raw materials used to prepare the outer ring secondary dissipation channel layer being 100%, the raw materials used to prepare the outer ring secondary dissipation channel layer contain 5-10 wt% GelMA, for example, 5 wt%, 6 wt%, 7 wt%, 8 wt%, 9 wt%, or 10 wt%.

[0048] Preferably, the modified nanofiller electret comprises any one or a combination of at least two of modified barium titanate, modified zinc oxide, modified MXene, or modified carbon nanotubes.

[0049] This invention defines the modified nanofiller electret as including any one or a combination of at least two of modified barium titanate, modified zinc oxide, modified MXene, or modified carbon nanotubes. Modified barium titanate effectively reduces the dielectric loss of the system and improves charge storage stability. Modified zinc oxide has a high content of phenolic hydroxyl groups on its surface, which can form strong coordination bonds with the coordinating crosslinking agent, significantly improving the dispersion uniformity and interfacial bonding stability of the modified nanofiller electret in the hydrogel matrix. Modified MXene can improve the overall flexibility and mechanical buffering performance of the material by utilizing interlayer slip properties. Modified carbon nanotubes optimize filler dispersion and improve the material's deformation adaptability through the regulation of surface flexible chains. These can be selected individually or in combination according to actual application requirements.

[0050] Preferably, the particle size distribution (CV) of the modified nanofiller electret in the outer ring secondary dissipation channel layer is ≤15%, for example, it can be 2%, 4%, 5%, 6%, 8%, 10%, 12%, 14% or 15%, etc.

[0051] Preferably, the interfacial binding energy of the modified nanofiller electret in the outer ring secondary dissipation channel layer is 50-100 mJ / m. 2 For example, it could be 50 mJ / m 2 60 mJ / m 2 80 mJ / m 2 or 100 mJ / m 2 wait.

[0052] The method for testing the CV value of dispersed particle size distribution is as follows: After freezing and fracturing the outer ring secondary dissipative channel layer sample and sputtering with gold, a scanning electron microscope is used to acquire microscopic images of the cross-section. ImageJ software is used to statistically analyze at least 10 groups of equivalent particle sizes of the filler particles, calculate the average particle size and standard deviation, and calculate the average particle size D for all particles. avg 1. Standard deviation of particle size (SD); 2. Coefficient of variation of dispersed particle size distribution (CV) formula: CV(%) = SD / D avg ×100%.

[0053] The interfacial binding energy testing method involved contact angle testing combined with calculation using the Owens-Wendt interfacial energy model. Thin sheets of pure modified nanofiller electret samples and thin sheets of outer ring secondary dissipation channel layers without pure modified nanofiller electret samples were pressed separately. The surface contact angles (denoted as θ1 and θ2) of the two sample materials were measured using water and diiodomethane as probe solutions, respectively. The dispersive components (denoted as γ) of the surface energy of the modified nanofiller electret and the outer ring secondary dissipation channel layer were then fitted to obtain their respective surface energies. d 1. γ d 2) Polar component (denoted as γ) p 1. γ p 2), Substitute into the two-phase adhesion work formula ( )Calculate the interface binding energy.

[0054] Preferably, the coordination crosslinking agent includes any one or a combination of at least two of the following: trivalent aluminum salt, divalent copper salt, divalent zinc salt, trivalent chromium salt, divalent cobalt salt, or divalent nickel salt.

[0055] Preferably, the coordination crosslinking agent is ferric chloride.

[0056] Preferably, the hydrogen bond enhancer includes any one or a combination of at least two of tannic acid, citric acid, gallic acid, polydopamine, dopamine, tannic acid derivatives, or ethylene glycol.

[0057] Preferably, the hydrogen bonding enhancer is tannic acid.

[0058] Preferably, the segment relaxation regulating component includes any one or at least two of the following: a combination of polyethylene glycol with different molecular weights, a combination of polypropylene glycol with different molecular weights, a combination of polylactic acid with different molecular weights, a combination of polycaprolactone with different molecular weights, or a combination of polyols with different molecular weights.

[0059] Preferably, the combination of polyethylene glycols with different molecular weights includes a combination of low-molecular-weight polyethylene glycol, medium-molecular-weight polyethylene glycol, and high-molecular-weight polyethylene glycol.

[0060] Preferably, the number average molecular weight of the oligomeric polyethylene glycol is 800-1200 g / mol, for example, it can be 800 g / mol, 900 g / mol, 1000 g / mol, 1100 g / mol or 1200 g / mol.

[0061] Preferably, the number average molecular weight of the polyethylene glycol is 8000-12000 g / mol, for example, it can be 8000 g / mol, 9000 g / mol, 10000 g / mol, 11000 g / mol or 12000 g / mol.

[0062] Preferably, the number average molecular weight of the high-polymer polyethylene glycol is 80,000-120,000 g / mol, for example, it can be 80,000 g / mol, 90,000 g / mol, 100,000 g / mol, 110,000 g / mol or 120,000 g / mol.

[0063] Preferably, the mass ratio of the oligomeric polyethylene glycol, the medium-polymer polyethylene glycol, and the high-polymer polyethylene glycol is 1:(0.8-1.2):(0.8-1.2).

[0064] Among them, 0.8-1.2 can be, for example, 0.8, 0.9, 1, 1.1 or 1.2, etc.

[0065] Preferably, solvent B comprises water.

[0066] Preferably, the raw materials for preparing the outer ring secondary dissipative channel layer include, by mass percentage, 5-8 wt% PVA, 5-10 wt% GelMA, 1-5 wt% polarized modified nanofiller electret, 0.1-0.3 wt% coordination crosslinking agent, 0.5-1 wt% hydrogen bond enhancer, 5-8 wt% segment relaxation regulating component, and 67.7-83.4 wt% solvent B.

[0067] Among them, 5-8 wt% can be, for example, 5 wt%, 5.5 wt%, 6 wt%, 6.5 wt%, 7 wt%, 7.5 wt%, or 8 wt%, etc.; 5-10 wt% can be, for example, 5 wt%, 6 wt%, 7 wt%, 8 wt%, 9 wt%, or 10 wt%, etc.; 1-5 wt% can be, for example, 1 wt%, 1.5 wt%, 2 wt%, 2.5 wt%, 3 wt%, 3.5 wt%, 4 wt%, 4.5 wt%, or 5 wt%, etc.; 0.1-0.3 wt% can be, for example, 0.1 wt%, 0.15 wt%, 0.2 wt%, 0.25 wt%, or 0.3 wt%, etc.; 0.5-1 wt% can be, for example, 0.5 wt%, 0.6 wt%, 0.7 wt%, 0.8 wt%, 0.9 wt%, or 1 wt%, etc.; 5-8 wt% can be, for example, 5 wt%, 6 wt%, 7 wt%, 8 wt%, 9 wt%, or 10 wt%, etc.; 1-5 wt% can be, for example, 1 wt%, 1.5 wt%, 2 wt%, 2.5 wt%, 3 wt%, 3.5 wt%, 4 wt%, 4.5 wt%, or 5 wt%, etc.; 0.1-0.3 wt% can be, for example, 0.1 wt%, 0.15 wt%, 0.2 wt%, 0.25 wt%, or 0.3 wt%, etc.; 0.5-1 wt% can be, for example, 0.5 wt%, 0.6 wt%, 0.7 wt%, 0 wt%, 5.5wt%, 6 wt%, 6.5 wt%, 7 wt%, 7.5 wt%, or 8 wt%, etc.; 67.7-83.4 wt%, for example, can be 67.7 wt%, 68wt%, 69 wt%, 80 wt%, 81 wt%, 82 wt%, 83 wt%, or 83.4 wt%, etc.

[0068] Preferably, the raw materials for preparing the modified barium titanate include barium titanate and a silane coupling agent.

[0069] Preferably, the mass ratio of barium titanate to silane coupling agent is 1:(0.01-0.03), for example, it can be 1:0.01, 1:0.015, 1:0.02, 1:0.025 or 1:0.03, etc.

[0070] Preferably, the barium titanate has a particle size distribution range of 50-200 nm, such as 50 nm, 100 nm, 150 nm or 200 nm.

[0071] Preferably, the silane coupling agent comprises γ-methacryloyloxypropyltrimethoxysilane (KH-570). Preferably, the modified barium titanate is subjected to thermal polarization treatment.

[0072] Preferably, the double bond density on the surface of the modified barium titanate is 0.5-1.0 mmol / g, for example, it can be 0.5 mmol / g, 0.6 mmol / g, 0.7 mmol / g, 0.8 mmol / g, 0.9 mmol / g or 1.0 mmol / g, etc.

[0073] Preferably, the covalent bond rate between the modified barium titanate and GelMA is ≥80%, for example, it can be 80%, 85%, 90% or 95%.

[0074] The double bond density on the surface of modified barium titanate was determined by the addition reaction of thiol groups with carbon-carbon double bonds. Using isopropanol thioglycolic acid solution (0.1 mol / L) as the reaction reagent, 1 g of modified barium titanate sample was mixed with 20 mL of isopropanol thioglycolic acid solution and stirred at room temperature (25℃) for 4 h in the dark to allow the thiol groups to fully react with the double bonds on the powder surface. After the reaction, the powder was separated by filtration. Using phenolphthalein as an indicator, the remaining thiol groups in the filtrate were titrated with sodium hydroxide standard solution (0.05 mol / L). The double bond density (mmol / g) was calculated according to the following formula: Double bond density (mmol / g) = (Amount of initial thiol substance - Amount of remaining thiol substance) / Mass of modified barium titanate sample.

[0075] The method for testing the covalent bonding rate between modified barium titanate and GelMA is as follows: Modified barium titanate sample and GelMA are mixed according to the formulation of the raw materials for preparing the outer ring dissipative channel layer. Free components are removed by water extraction for 24 h, and the sample is prepared by vacuum drying at 60℃. A pure modified barium titanate sample is also prepared. Thermogravimetric analysis (TGA) is performed on both the sample and the pure modified barium titanate sample under a nitrogen atmosphere at a rate of 10℃ / min, increasing the temperature from room temperature (25℃) to 600℃. Organic thermogravimetric data are recorded, and the covalent bonding rate (%) between modified barium titanate and GelMA is calculated using the following formula: The covalent bond rate (%) of modified barium titanate to GelMA = (organic thermal weight loss of the sample to be tested - weight loss of pure modified barium titanate sample) / theoretical amount of GelMA added × 100%.

[0076] Preferably, the modified barium titanate is prepared by the following method, the preparation method comprising: Barium titanate was dispersed in solvent E, a silane coupling agent was added to react, and then thermally polarized to obtain the modified barium titanate.

[0077] Preferably, the solvent E comprises ethanol.

[0078] Preferably, the concentration of barium titanate in solvent E is 8-12 mg / mL, for example, it can be 8 mg / mL, 9 mg / mL, 10 mg / mL, 11 mg / mL or 12 mg / mL, etc.

[0079] Preferably, the dispersion is performed under ultrasound.

[0080] Preferably, the dispersion time is 20-40 min, for example, it can be 20 min, 25 min, 30 min, 35 min or 40 min.

[0081] Preferably, the reaction temperature is 55-65℃, for example, 55℃, 56℃, 58℃, 60℃, 62℃, 64℃ or 65℃, and the reaction time is 1-3 h, for example, 1 h, 1.5 h, 2 h, 2.5 h or 3 h.

[0082] Preferably, the reaction is followed by centrifugation and drying steps.

[0083] Preferably, the centrifugation speed is 6000-10000 rpm, for example, it can be 6000, 7000, 8000, 9000 or 10000 rpm.

[0084] Preferably, the drying temperature is 55-65℃, for example, 55℃, 56℃, 58℃, 60℃, 62℃, 64℃ or 65℃, and the drying time is 1-3 h, for example, 1 h, 1.5 h, 2 h, 2.5 h or 3 h.

[0085] Preferably, the temperature of the thermal polarization treatment is 65-75℃, for example, it can be 65℃, 66℃, 68℃, 70℃, 72℃, 74℃ or 75℃, etc.

[0086] Preferably, the thermal polarization treatment is performed under an electric field.

[0087] Preferably, the electric field strength is 2-4 kV / mm, for example, it can be 2 kV / mm, 2.5 kV / mm, 3 kV / mm, 3.5 kV / mm or 4 kV / mm, etc.

[0088] Preferably, the thermal polarization treatment time is 15-25 min, for example, it can be 15 min, 16 min, 18 min, 20 min, 22 min, 24 min or 25 min, etc.

[0089] Preferably, the raw materials for preparing the modified zinc oxide include zinc oxide and tannic acid.

[0090] Preferably, the particle size distribution range of the zinc oxide is 30-100 nm, for example, it can be 30 nm, 40 nm, 50 nm, 60 nm, 80 nm or 100 nm.

[0091] Preferably, the mass ratio of zinc oxide to tannic acid is 1:(0.005-0.01), for example, it can be 1:0.005, 1:0.006, 1:0.007, 1:0.008, 1:0.009 or 1:0.01, etc.

[0092] Preferably, the modified zinc oxide is subjected to corona polarization treatment.

[0093] Preferably, the density of the surface phenolic hydroxyl groups of the modified zinc oxide is 1.0-2.0 mmol / g, for example, it can be 1.0 mmol / g, 1.2 mmol / g, 1.4 mmol / g, 1.5 mmol / g, 1.6 mmol / g, 1.8 mmol / g or 2.0 mmol / g, etc.

[0094] Preferably, the coordination bond constant between the modified zinc oxide and the coordination crosslinking agent is ≥10. 5 L / mol, for example, could be 10 5 L / mol, 2×10 5 L / mol, 5×10 5 L / mol, 8×10 5 L / mol or 10 6 L / mol, etc.

[0095] The density of phenolic hydroxyl groups on the surface of modified zinc oxide was determined using the Folin-Ciocalteu spectrophotometric method. First, Folin-Ciocalteu reagent (0.2 mol / L) was prepared. A modified zinc oxide sample was taken, and water was added. The sample was shaken at room temperature (25℃) to extract free phenolic hydroxyl groups. After centrifugation, the supernatant was collected. Sodium carbonate solution (12 wt%) and Folin-Ciocalteu reagent were added sequentially. For every 1 mL of supernatant, 1.5 mL of sodium carbonate solution and 0.5 mL of Folin-Ciocalteu reagent were added. The mixture was incubated in the dark at room temperature (25℃) for 30 min, and the absorbance was measured at 765 nm. The amount of phenolic hydroxyl groups was obtained using a standard curve. Finally, the density of phenolic hydroxyl groups (mmol / g) was calculated by the ratio of the total amount of phenolic hydroxyl groups to the mass of the modified zinc oxide sample.

[0096] The coordination bond constant between modified zinc oxide and the coordination crosslinking agent was tested using the following method: Modified zinc oxide was prepared as a zinc oxide suspension (2 g / L). With the concentration of the modified zinc oxide suspension fixed, 0.2703 g of ferric chloride hexahydrate was weighed, dissolved in water, and brought to a final volume of 100 mL to obtain a ferric chloride coordination crosslinking agent solution. The ferric chloride coordination crosslinking agent solution was then added dropwise to the modified zinc oxide suspension at room temperature (25℃). The concentration gradients of the three iron ions in the mixed system were 0 mol / L, 0.0005 mol / L, 0.001 mol / L, 0.002 mol / L, 0.003 mol / L, 0.004 mol / L, 0.005 mol / L, and 0.006 mol / L, respectively. Each mixed system was sealed and stored at room temperature (25℃) in the dark. The concentrations were increased every 2... The supernatant was centrifuged to remove the modified zinc oxide powder. The characteristic absorbance of the mixed system at 520 nm was measured using a UV-Vis spectrophotometer. When the absorbance difference measured at three consecutive intervals was ≤0.005, the system reached coordination equilibrium. At this time, the absorbance of the characteristic absorption peaks of each system was measured using a UV-Vis spectrophotometer. The coordination bond binding constant between the modified zinc oxide and the coordination crosslinking agent was calculated by fitting the Benesi-Hildebrand equation.

[0097] Preferably, the modified zinc oxide is prepared by the following method, the preparation method comprising: Zinc oxide was dispersed in solvent F, tannic acid was added to react, and then corona polarization treatment was performed to obtain the modified zinc oxide.

[0098] Preferably, the solvent F includes ethanol.

[0099] Preferably, the concentration of zinc oxide in solvent F is 8-12 mg / mL, for example, it can be 8 mg / mL, 9 mg / mL, 10 mg / mL, 11 mg / mL or 12 mg / mL, etc.

[0100] Preferably, the dispersion is performed under ultrasound.

[0101] Preferably, the dispersion time is 20-40 min, for example, it can be 20 min, 25 min, 30 min, 35 min or 40 min.

[0102] Preferably, the reaction temperature is 55-65℃, for example, 55℃, 56℃, 58℃, 60℃, 62℃, 64℃ or 65℃, and the reaction time is 1-3 h, for example, 1 h, 1.5 h, 2 h, 2.5 h or 3 h.

[0103] Preferably, the reaction is followed by centrifugation and drying steps.

[0104] Preferably, the centrifugation speed is 6000-10000 rpm, for example, it can be 6000, 7000, 8000, 9000 or 10000 rpm.

[0105] Preferably, the drying temperature is 55-65℃, for example, 55℃, 56℃, 58℃, 60℃, 62℃, 64℃ or 65℃, and the drying time is 1-3 h, for example, 1 h, 1.5 h, 2 h, 2.5 h or 3 h.

[0106] Preferably, the temperature of the corona polarization treatment is 20-30℃, for example, it can be 20℃, 22℃, 24℃, 25℃, 26℃, 28℃ or 30℃.

[0107] Preferably, the voltage of the corona polarization treatment is 8-12 kV, for example, it can be 8 kV, 9 kV, 10 kV, 11 kV or 12 kV.

[0108] Preferably, the corona polarization treatment time is 10-20 min, for example, it can be 10 min, 12 min, 14 min, 15 min, 16 min, 18 min or 20 min, etc.

[0109] Preferably, the modified MXene is prepared by the following method, the preparation method comprising: The modified MXene was obtained by subjecting MXene to plasma treatment and corona polarization treatment.

[0110] Preferably, the MXene is dispersed in solvent G.

[0111] Preferably, the solvent G comprises water.

[0112] Preferably, the concentration of MXene in solvent G is 1-3 mg / mL, for example, it can be 1 mg / mL, 1.5 mg / mL, 2 mg / mL, 2.5 mg / mL or 3 mg / mL, etc.

[0113] Preferably, the MXene has a wafer size distribution range of 500-1000 nm, such as 500 nm, 600 nm, 700 nm, 800 nm, 900 nm or 1000 nm.

[0114] Preferably, the thickness of the MXene is 1-5 nm, for example, it can be 1 nm, 2 nm, 3 nm, 4 nm or 5 nm, etc.

[0115] Preferably, the plasma treatment and the corona polarization treatment are each performed independently in an inert gas atmosphere.

[0116] Preferably, the inert gas includes argon.

[0117] Preferably, the power of the plasma treatment is 80-120 W, for example, it can be 80 W, 85 W, 90 W, 95 W, 100 W, 105 W, 110 W, 115 W or 120 W, etc.

[0118] Preferably, the plasma treatment time is 30-60 s, for example, it can be 30 s, 35 s, 40 s, 45 s, 50 s, 55 s or 60 s, etc.

[0119] Preferably, the voltage of the corona polarization treatment is 7-10 kV, for example, it can be 7 kV, 8 kV, 9 kV or 10 kV.

[0120] Preferably, the corona polarization treatment time is 8-15 min, for example, it can be 8 min, 9 min, 10 min, 11 min, 12 min, 13 min, 14 min or 15 min, etc.

[0121] Preferably, the percentage of hydroxyl terminator sites on the surface of the modified MXene is 30-50%, for example, it can be 30%, 35%, 40%, 45% or 50%.

[0122] The site ratio of surface hydroxyl terminators was measured using X-ray photoelectron spectroscopy (XPS). The modified MXene was vacuum dried at 60℃, and the O1s fine spectrum was acquired by XPS and peak fitting was performed to distinguish three types of oxygen signals: lattice Ti-O, Ti-OH, and adsorbed water. After deducting the peak area of ​​adsorbed water, the site ratio of surface hydroxyl terminators of the modified MXene was calculated by the ratio of the integrated area of ​​the Ti-OH characteristic peak to the total peak area of ​​oxygen-containing end groups on the surface.

[0123] Preferably, the raw materials for preparing the modified carbon nanotubes include carbon nanotubes and polyethylene glycol.

[0124] Preferably, the mass ratio of carbon nanotubes to polyethylene glycol is 1:(0.8-1.2), for example, it can be 1:0.8, 1:0.9, 1:1, 1:1.1 or 1:1.2, etc.

[0125] Preferably, the diameter of the carbon nanotube is 5-20 nm, for example, it can be 5 nm, 6 nm, 8 nm, 10 nm, 12 nm, 14 nm, 15 nm, 16 nm, 18 nm or 20 nm, etc.

[0126] Preferably, the length of the carbon nanotube is 100-500 nm, for example, it can be 100 nm, 200 nm, 300 nm, 400 nm or 500 nm.

[0127] Preferably, the number-average molecular weight of the polyethylene glycol is 1800-2200 g / mol, for example, it can be 1800 g / mol, 1900 g / mol, 2000 g / mol, 2100 g / mol or 2200 g / mol.

[0128] Preferably, the modified carbon nanotubes are subjected to thermal polarization treatment.

[0129] Preferably, the surface grafting rate of the modified carbon nanotubes is 30-50%, for example, it can be 30%, 35%, 40%, 45% or 50%, etc.

[0130] The surface grafting rate was determined using the following method: using pure carbon nanotubes as the blank sample, the modified carbon nanotube sample and the blank sample were placed in a nitrogen atmosphere, and the temperature was increased from 10℃ to 600℃ at a rate of 10℃ / min. The difference in weight loss between the blank sample and the modified carbon nanotube sample was recorded as organic thermal weight loss. The surface grafting rate (%) was calculated according to the following formula: Surface grafting rate (%) = Organic thermal weight loss / Theoretical feed mass of polyethylene glycol × 100%.

[0131] Preferably, the modified carbon nanotubes are prepared by the following method, the preparation method comprising: Carbon nanotubes were dispersed in solvent H, polyethylene glycol was added to react, and then thermally polarized to obtain the modified carbon nanotubes.

[0132] Preferably, the solvent H comprises DMSO.

[0133] Preferably, the concentration of the carbon nanotubes in solvent H is 8-12 mg / mL, for example, it can be 8 mg / mL, 9 mg / mL, 10 mg / mL, 11 mg / mL or 12 mg / mL, etc.

[0134] Preferably, the reaction temperature is 55-65℃, for example, 55℃, 56℃, 58℃, 60℃, 62℃, 64℃ or 65℃, and the reaction time is 2-5 h, for example, 2 h, 3 h, 4 h or 5 h.

[0135] Preferably, the reaction further includes dialysis and drying steps.

[0136] Preferably, the molecular weight cutoff for dialysis is 3-4 kDa, for example, it can be 3 kDa, 3.2 kDa, 3.4 kDa, 3.5 kDa, 3.6 kDa, 3.8 kDa or 4 kDa, etc.

[0137] Preferably, the dialysis time is 40-50 hours, for example, 40 hours, 42 hours, 44 hours, 45 hours, 46 hours, 48 ​​hours, or 50 hours.

[0138] Preferably, the drying includes freeze drying.

[0139] Preferably, the temperature of the thermal polarization treatment is 80-120°C, for example, it can be 80°C, 90°C, 100°C, 110°C or 120°C.

[0140] Preferably, the thermal polarization treatment is performed under an electric field.

[0141] Preferably, the electric field strength is 1.5-3 kV / mm, for example, it can be 1.5 kV / mm, 2 kV / mm, 2.5 kV / mm or 3 kV / mm, etc.

[0142] Preferably, the thermal polarization treatment time is 10-18 min, for example, it can be 10 min, 11 min, 12 min, 13 min, 14 min, 15 min, 16 min, 17 min or 18 min, etc.

[0143] Preferably, the energy storage modulus of the outer ring secondary dissipation channel layer is 1-5 kPa, for example, it can be 1 kPa, 2 kPa, 3 kPa, 4 kPa or 5 kPa.

[0144] The energy storage modulus was tested using a dynamic thermomechanical analyzer (DMA). The outer ring secondary dissipation channel layer was cut into a cuboid strip with dimensions of 15 mm × 5 mm × 4 mm. The compression mode was selected, and the test temperature was set to 25℃, the frequency to 1 Hz, and the dynamic strain to 0.5%. The instrument directly output the energy storage modulus in kPa.

[0145] The outer ring secondary dissipation channel layer provided by this invention combines polarized modified nanofiller electret, coordination crosslinking agent, hydrogen bond enhancer, and segment relaxation regulating component. The coordination crosslinking agent and hydrogen bond enhancer serve as dynamic bond regulating components. Through the formation of mid-frequency responsive coordination bonds between the coordination crosslinking agent and the hydrogel matrix, and the formation of low-frequency responsive hydrogen bonds between the hydrogen bond enhancer and the hydrogel matrix, dual dynamic reversible breakage and recombination are achieved. The dynamic bond synergistic units form a multi-scale energy dissipation mechanism, enhancing dynamic bond energy dissipation. The polarized modified nanofiller electret serves as an interfacial polarization dissipation unit, selecting high... Dielectric nanofillers (modified barium titanate, modified zinc oxide, modified MXene, or modified carbon nanotubes) enhance low-frequency dissipation through interfacial polarization and charge hysteresis effects. Furthermore, by modifying the electret of the nanofillers and synergistically regulating multiple types of interfacial interactions (hydrogen bonds, coordination bonds, etc.), the dispersibility and interfacial bonding strength of the fillers can be improved, thereby reducing the fluctuation of the loss factor and achieving stable and controllable damping performance. Further compounding with polyethylene glycol of different molecular weights as a segment relaxation regulating component can effectively broaden the segment relaxation time distribution of the system. The multi-mechanism damping regulation system synergistically achieves efficient dissipation of low-frequency mechanical noise in the 0.1-10 Hz range and maintains low-interference transmission in the 0.5-100 Hz electrophysiological signal frequency band.

[0146] Preferably, the diameter of the inner ring main conductive channel layer is 5-8 mm, for example, it can be 5 mm, 5.5 mm, 6 mm, 6.5 mm, 7 mm, 7.5 mm or 8 mm, etc.

[0147] Preferably, the outer diameter of the outer ring secondary dissipation channel layer is 10-15 mm, for example, it can be 10 mm, 11 mm, 12 mm, 13 mm, 14 mm or 15 mm, etc.

[0148] Preferably, the thickness of the dual-ring conductive hydrogel brain-computer interface electrode structure is 3-10 mm, for example, it can be 3 mm, 4 mm, 5 mm, 6 mm, 7 mm, 8 mm, 9 mm or 10 mm.

[0149] Preferably, the dual-ring conductive hydrogel brain-computer interface electrode structure has an asymmetric interface functional layer along the thickness direction.

[0150] Preferably, the asymmetric interface functional layer includes a modified hydrophilic layer and a modified hydrophobic layer respectively disposed on both sides along the thickness direction of the double-ring conductive hydrogel brain-computer interface electrode structure.

[0151] Preferably, the modified hydrophilic layer comprises, by mass percentage, 1-5 wt% hydrophilic agent, 0-1 wt% humectant, 0-0.5 wt% electrolyte, and 95-98% solvent C.

[0152] Among them, 1-5 wt% can be, for example, 1 wt%, 2 wt%, 3 wt%, 4 wt%, or 5 wt%; 0-1 wt% can be, for example, 0 wt%, 0.2 wt%, 0.4 wt%, 0.5 wt%, 0.6 wt%, 0.8 wt%, or 1 wt%; 0-0.5 wt% can be, for example, 0 wt%, 0.1 wt%, 0.2 wt%, 0.3 wt%, 0.4 wt%, or 0.5 wt%; 95-98% can be, for example, 95%, 96%, 97%, or 98%.

[0153] Preferably, the hydrophilic agent comprises sodium pyrrolidone carboxylate.

[0154] Preferably, the moisturizer includes glycerin.

[0155] Preferably, the electrolyte comprises sodium chloride.

[0156] Preferably, the solvent C comprises water.

[0157] Preferably, the modified hydrophobic layer comprises, by mass percentage, 1-5 wt% fluorosilane coupling agent and 95-99% solvent D.

[0158] Among them, 1-5 wt% can be, for example, 1 wt%, 2 wt%, 3 wt%, 4 wt% or 5 wt%; 95-99% can be, for example, 95%, 96%, 97%, 98% or 99% or so.

[0159] Preferably, the solvent D comprises water.

[0160] Preferably, the fluorosilane coupling agent comprises a long-chain perfluoroalkylsilane.

[0161] Preferably, the long-chain perfluoroalkylsilane includes any one or a combination of at least two of 1H,1H,2H,2H-perfluorooctyltriethoxysilane, 1H,1H,2H,2H-perfluorodecyltrimethoxysilane, or 1H,1H,2H,2H-perfluorodecyltriethoxysilane.

[0162] Preferably, the adhesion strength of the modified hydrophilic layer is 10-25 kPa, for example, it can be 10 kPa, 12 kPa, 14 kPa, 15 kPa, 16 kPa, 18 kPa, 20 kPa, 22 kPa, 24 kPa or 25 kPa.

[0163] Preferably, the adhesion strength of the modified hydrophobic layer is ≤ 3 kPa, for example, it can be 0.5 kPa, 1 kPa, 1.5 kPa, 2 kPa, 2.5 kPa or 3 kPa.

[0164] The adhesion strength was tested in accordance with GB / T 2790-1995 "Adhesives - 180° Peel Strength Test Method".

[0165] This invention uses long-chain perfluoroalkyl silane, which has mild hydrolysis, high grafting rate with hydroxyl groups on the surface of hydrogel, and forms a low surface energy hydrophobic layer, meeting the requirements of adhesion strength ≤3 kPa and easy disassembly and reuse, and is suitable for hydrophobic modification scenarios of hydrogel.

[0166] This invention utilizes an asymmetric interface functional layer (Janus interface functional layer) along the thickness direction of a dual-ring conductive hydrogel brain-computer interface electrode structure. A modified hydrophilic layer is formed on the skin-friendly side, while a modified hydrophobic layer is formed on the device side. The hydrophilic agent forms a hydrogen bond network with the skin's stratum corneum, glycerol forms a moisture-retaining layer, and the electrolyte enhances ion migration, thereby reducing interfacial contact impedance and improving signal stability. A fluorosilane coupling agent forms a low surface energy layer, inhibiting interfacial adhesion and enabling easy disassembly and reusability. The asymmetric interface functional layer design ensures good adhesion while reducing skin irritation and significantly reduces interfacial impedance fluctuations during repeated use, making it suitable for long-term continuous monitoring scenarios.

[0167] In a second aspect, the present invention provides a method for preparing a dual-ring conductive hydrogel brain-computer interface electrode structure as described in the first aspect, the method comprising the following steps: (1) Mix the raw materials for preparing the inner ring main conductive channel layer to obtain mixed solution A; The raw materials for preparing the outer ring secondary dissipation channel layer were mixed to obtain mixed solution B; (2) Inject the mixed solution A into the inner ring of the double-ring mold for pre-crosslinking treatment, and then inject the mixed solution B into the outer ring of the double-ring mold for crosslinking treatment to obtain the double-ring conductive hydrogel brain-computer interface electrode structure.

[0168] Preferably, the mixing of raw materials for preparing the inner ring main conductive channel layer in step (1) includes a first stage mixing, a second stage mixing, and a third stage mixing.

[0169] Preferably, the first stage of mixing in step (1) includes mixing the hydrogel matrix A and the solvent A.

[0170] Preferably, the second stage mixing includes mixing the mixture obtained after the first stage mixing with the electronically conductive component and the functional nanoparticles.

[0171] Preferably, the electronically conductive filler in the electronically conductive component is pre-ultrasonicated before the second stage of mixing.

[0172] Preferably, the third stage mixing includes mixing the mixture obtained after the second stage mixing with the ion-conducting component.

[0173] Preferably, the mixing temperature in the first stage is 90-100℃, such as 90℃, 92℃, 94℃, 95℃, 96℃, 98℃ or 100℃, and the time is 30-60 min, such as 30 min, 40 min, 50 min or 60 min.

[0174] Preferably, the mixing temperature in the second stage is 60-70°C, for example, 60°C, 62°C, 64°C, 65°C, 66°C, 68°C, or 70°C, and the time is 20-40 min, for example, 20 min, 25 min, 30 min, 35 min, or 40 min.

[0175] Preferably, the mixing temperature in the third stage is 60-70℃, for example, 60℃, 62℃, 64℃, 65℃, 66℃, 68℃ or 70℃, and the time is 20-40 min, for example, 20 min, 25 min, 30 min, 35 min or 40 min.

[0176] Preferably, the third stage of mixing further includes a vacuum degassing step.

[0177] Preferably, the vacuum degree of the vacuum degassing after the third stage of mixing is -0.05 to -0.1 MPa, for example, it can be -0.05 MPa, -0.06 MPa, -0.08 MPa or -0.1 MPa, etc., and the time is 5-15 min, for example, it can be 5 min, 6 min, 8 min, 10 min, 12 min, 14 min or 15 min, etc.

[0178] Preferably, the mixing of the raw materials for preparing the outer ring secondary dissipation channel layer in step (1) includes a first mixing, a second mixing, and a third mixing.

[0179] Preferably, the first mixing includes mixing the hydrogel matrix B and the solvent B.

[0180] Preferably, the second mixing includes mixing the mixture obtained after the first mixing with the modified nanofiller electret, hydrogen bond enhancer and segment relaxation modulator.

[0181] Preferably, the third mixing includes mixing the mixture obtained after the second mixing with a coordination crosslinking agent.

[0182] Preferably, the temperature of the first mixing is 85-90℃, for example, 85℃, 86℃, 87℃, 88℃, 89℃ or 90℃, and the time is 35-45 min, for example, 35 min, 36 min, 38 min, 40 min, 42 min, 44 min or 45 min.

[0183] Preferably, the temperature of the second mixing is 50-60℃, for example, 50℃, 52℃, 54℃, 55℃, 56℃, 58℃ or 60℃, and the time is 20-40 min, for example, 20 min, 25 min, 30 min, 35 min or 40 min.

[0184] Preferably, the temperature of the third mixing is 50-60℃, for example, 50℃, 52℃, 54℃, 55℃, 56℃, 58℃ or 60℃, and the time is 20-40 min, for example, 20 min, 25 min, 30 min, 35 min or 40 min.

[0185] Preferably, the third mixing process further includes a vacuum degassing step.

[0186] Preferably, the vacuum degree of the vacuum degassing after the third mixing is -0.05 to -0.1 MPa, for example, it can be -0.05 MPa, -0.06 MPa, -0.08 MPa or -0.1 MPa, etc., and the time is 5-15 min, for example, it can be 5 min, 6 min, 8 min, 10 min, 12 min, 14 min or 15 min, etc.

[0187] Preferably, the temperature of the pre-crosslinking treatment in step (2) is -15 to -5℃, for example, it can be -15℃, -12℃, -10℃, -8℃, -6℃ or -5℃, etc., and the time is 10-20 min, for example, it can be 10 min, 12 min, 14 min, 15 min, 16 min, 17 min, 18 min, 19 min or 20 min, etc.

[0188] Preferably, the temperature of the crosslinking treatment in step (2) is -45~-35℃, for example, it can be -45℃, -42℃, -40℃, -38℃, -36℃ or -35℃, etc., and the time is 25-35 min, for example, it can be 25 min, 26 min, 28 min, 30 min, 32 min, 34 min or 35 min, etc.

[0189] Preferably, the preparation method further includes performing hydrophilic modification treatment and hydrophobic modification treatment on both sides along the thickness direction of the hydrogel after crosslinking treatment in step (2).

[0190] Preferably, the hydrophilic modification treatment includes the following steps: The components of the modified hydrophilic layer are mixed to obtain a mixed solution C; one side of the hydrogel is immersed in the mixed solution C to complete the hydrophilic modification treatment.

[0191] Preferably, the immersion time is 10-15 min, for example, 10 min, 11 min, 12 min, 13 min, 14 min or 15 min.

[0192] Preferably, the impregnation process further includes standing at 20-30°C (e.g., 20°C, 22°C, 24°C, 25°C, 26°C, 28°C, or 30°C, etc.) for 10-30 minutes (e.g., 10 minutes, 15 minutes, 20 minutes, 25 minutes, or 30 minutes, etc.).

[0193] Preferably, the hydrophobic modification treatment includes the following steps: The components of the modified hydrophobic layer are mixed to obtain a mixed solution D; the mixed solution D is sprayed onto the other side surface of the hydrogel to complete the hydrophobic modification treatment.

[0194] Preferably, after spraying, the coating is further subjected to a standing temperature of 20-30℃ (e.g., 20℃, 22℃, 24℃, 25℃, 26℃, 28℃ or 30℃, etc.) for 10-30 minutes (e.g., 10 minutes, 15 minutes, 20 minutes, 25 minutes or 30 minutes, etc.).

[0195] Thirdly, the present invention provides an application of the dual-ring conductive hydrogel brain-computer interface electrode structure as described in the first aspect in an electrophysiological signal acquisition system.

[0196] Compared with the prior art, the present invention has at least the following beneficial effects: The dual-ring conductive hydrogel brain-computer interface electrode structure provided by this invention features wideband mechanical damping and active noise reduction. Through spatial partitioning design, it achieves physical separation of the conductive path and the dissipation path. Combined with the formulation design of the inner ring main conductive channel layer and the outer ring secondary dissipation channel layer, it synergistically achieves the response characteristics of "high dissipation of low-frequency mechanical noise - low interference of target signal frequency band" (achieving efficient energy dissipation in the 0.1-10 Hz mechanical noise frequency band, while maintaining low interference transmission in the 0.5-100 Hz electrophysiological signal frequency band). Furthermore, by setting an asymmetric interface functional layer along the thickness direction of the dual-ring conductive hydrogel brain-computer interface electrode structure, it reduces interface contact impedance, improves signal stability, inhibits interface adhesion, and achieves easy disassembly and reusability. It achieves synergistic optimization of conductivity, damping performance, and interface impedance in the same electrode system, and is suitable for dynamic high-fidelity acquisition of non-invasive electrophysiological signals such as EEG. It can be integrated into brain-computer interfaces, wearable medical devices, transcranial nerve modulation systems, and other terminal products. Attached Figure Description

[0197] Figure 1 This is a SEM image of the microstructure of the inner ring main conductive channel layer in the dual-ring conductive hydrogel brain-computer interface electrode structure provided in Embodiment 1 of the present invention, with a scale bar of 200 μm. Figure 2 This is a SEM image of the microstructure of the outer ring secondary dissipative channel layer in the dual-ring conductive hydrogel brain-computer interface electrode structure provided in Embodiment 1 of the present invention, with a scale bar of 200 μm. Figure 3 This is a SEM image of the microstructure of the outer ring secondary dissipative channel layer in the dual-ring conductive hydrogel brain-computer interface electrode structure provided in Embodiment 2 of the present invention, with a scale bar of 200 μm. Figure 4 This is a SEM image of the microstructure of the outer ring secondary dissipative channel layer in the dual-ring conductive hydrogel brain-computer interface electrode structure provided in Embodiment 3 of the present invention, with a scale bar of 200 μm. Figure 5 This is a SEM image of the microstructure of the outer ring secondary dissipative channel layer in the dual-ring conductive hydrogel brain-computer interface electrode structure provided in Embodiment 5 of the present invention, with a scale bar of 200 μm. Figure 6 This is a SEM image of the microstructure of the outer ring secondary dissipative channel layer in the dual-ring conductive hydrogel brain-computer interface electrode structure provided in Comparative Example 1 of this invention, with a scale bar of 200 μm. Figure 7 This is a SEM image of the microstructure of the outer ring secondary dissipative channel layer in the dual-ring conductive hydrogel brain-computer interface electrode structure provided in Comparative Example 2 of this invention. The scale bar is 200 μm. Figure 8This is a SEM image of the microstructure of the conductive hydrogel structure provided in Comparative Example 3 of the present invention, with a scale bar of 200 μm. Figure 9 These are the compressive stress-compressive strain test diagrams of the dual-ring conductive hydrogel brain-computer interface electrode structures provided in Embodiments 1-5 and Comparative Examples 1-3 of this invention. Figure 10 These are the compression modulus test diagrams of the dual-ring conductive hydrogel brain-computer interface electrode structures provided in Embodiments 1-5 and Comparative Examples 1-3 of this invention. Figure 11 The image shows the compressive stress-compressive strain test results of the dual-ring conductive hydrogel brain-computer interface electrode structure provided in Embodiment 1 of this invention after 47 compression cycles. The range of compressive stress is 0-0.2 MPa, and the range of compressive strain is 0-50%. Figure 12 This is a test diagram of the compression stress-compression time of the dual-ring conductive hydrogel brain-computer interface electrode structure provided in Embodiment 1 of the present invention after 47 compression cycles. Figure 13 This is a cyclic voltammetry curve of the dual-ring conductive hydrogel brain-computer interface electrode structure provided in Embodiment 1 of the present invention; Figure 14 This is a cyclic voltammetry curve of the dual-ring conductive hydrogel brain-computer interface electrode structure provided in Embodiment 3 of the present invention; Figure 15 This is a cyclic voltammetry curve of the dual-ring conductive hydrogel brain-computer interface electrode structure provided in Embodiment 5 of the present invention; Figure 16 This is a cyclic voltammetry curve of the dual-ring conductive hydrogel brain-computer interface electrode structure provided in Comparative Example 1 of this invention. Figure 17 This is a cyclic voltammetry test curve of the dual-ring conductive hydrogel brain-computer interface electrode structure provided in Comparative Example 3 of the present invention. Figure 18 This is the impedance-frequency test curve of the dual-ring conductive hydrogel brain-computer interface electrode structure provided in Embodiment 1 of the present invention; Figure 19 This is the impedance-frequency test curve of the dual-ring conductive hydrogel brain-computer interface electrode structure provided in Embodiment 3 of the present invention; Figure 20 This is the impedance-frequency test curve of the dual-ring conductive hydrogel brain-computer interface electrode structure provided in Embodiment 5 of the present invention; Figure 21 This is the impedance-frequency test curve of the dual-ring conductive hydrogel brain-computer interface electrode structure provided in Comparative Example 1 of the present invention. Figure 22 This is the impedance-frequency test curve of the dual-ring conductive hydrogel brain-computer interface electrode structure provided in Comparative Example 3 of the present invention. Figure 23 This is a phase angle-frequency test curve of the dual-ring conductive hydrogel brain-computer interface electrode structure provided in Embodiment 1 of the present invention; Figure 24 This is a phase angle-frequency test curve of the dual-ring conductive hydrogel brain-computer interface electrode structure provided in Embodiment 3 of the present invention; Figure 25 This is a phase angle-frequency test curve of the dual-ring conductive hydrogel brain-computer interface electrode structure provided in Embodiment 5 of the present invention; Figure 26 This is a phase angle-frequency test curve of the dual-ring conductive hydrogel brain-computer interface electrode structure provided in Comparative Example 1 of this invention; Figure 27 This is a phase angle-frequency test curve of the dual-ring conductive hydrogel brain-computer interface electrode structure provided in Comparative Example 3 of the present invention. Figure 28 This is a test diagram of the electrode signal input-output performance of the dual-ring conductive hydrogel brain-computer interface electrode structure provided in Embodiment 1 of the present invention. The voltage range is -1.0~1.0 V, and the time range is -2~2 s. Figure 29 This is a test diagram of the electrode signal input-output performance of the dual-ring conductive hydrogel brain-computer interface electrode structure provided in Embodiment 1 of the present invention. The voltage range is -1.0~1.0 V, and the time range is -0.04~0.04 s. Figure 30 The image shows an EEG test of the double-ring conductive hydrogel brain-computer interface electrode structure provided in Embodiment 1 of the present invention, with a time range of 0-150 s. Figure 31 The image shows an EEG test of the dual-ring conductive hydrogel brain-computer interface electrode structure provided in Embodiment 1 of the present invention, with a time range of 60-70 s. Detailed Implementation

[0198] The technical solution of the present invention will be further described below with reference to the accompanying drawings and specific embodiments. However, the following examples are merely simplified examples of the present invention and do not represent or limit the scope of protection of the present invention. The scope of protection of the present invention is determined by the claims.

[0199] The specific information of the materials used in the following specific embodiments of the present invention is as follows: PVA, with a degree of alcoholysis of 99% and a degree of polymerization of 1750±50, was purchased from Sinopharm Chemical Reagent Co., Ltd. PVP, K30, purchased from Aladdin Reagent Co., Ltd. GelMA, 70% methacrylamide, purchased from Shanghai Maclean Biochemical Technology Co., Ltd. Silver nanowires, with a single filament diameter of 50 nm and a length of 50 μm, were purchased from Beijing Zhongke Keyou Technology Co., Ltd. Poly(3,4-ethylenedioxythiophene): polystyrene sulfonate, Clevios PH1000; 1-Butyl-3-methylimidazolium tetrafluoroborate, [BMIM]BF4, purchased from Aladdin Reagent Co., Ltd. Zinc oxide with a particle size distribution range of 30-100 nm was purchased from Shanghai Maclean Biochemical Technology Co., Ltd. The oligomeric polyethylene glycol, with a number average molecular weight of 1000 g / mol, was purchased from Shanghai Maclean Biochemical Technology Co., Ltd. Medium-sized polyethylene glycol with a number average molecular weight of 10,000 g / mol was purchased from Shanghai Maclean Biochemical Technology Co., Ltd. High-molecular-weight polyethylene glycol with a number average molecular weight of 100,000 g / mol was purchased from Shanghai Maclean Biochemical Technology Co., Ltd. The modified barium titanate used in the following examples and comparative examples was prepared by the following method: Barium titanate (particle size distribution range of 50-200 nm, purchased from Aladdin Reagent Co., Ltd.) was ultrasonically dispersed with ethanol for 30 min, with the concentration of barium titanate in ethanol being 10 mg / mL. KH-570 (mass ratio of barium titanate to silane coupling agent of 1:0.03) was added and reacted at 60 °C for 2 h. After centrifugation at 8000 rpm and drying at 60 °C for 2 h, the dried powder was subjected to thermal polarization treatment under an electric field of 3 kV / mm and 70 °C for 20 min to obtain the modified barium titanate (the double bond density on the surface is 0.5 mmol / g, and the covalent bond binding rate with GelMA is 85%). The modified zinc oxide used in the following examples and comparative examples was prepared by the following method: Zinc oxide (particle size distribution range of 30-100 nm, purchased from Shanghai Maclean Biochemical Technology Co., Ltd.) was ultrasonically dispersed in ethanol for 30 min, with a zinc oxide concentration of 10 mg / mL in ethanol. Tannic acid (mass ratio of zinc oxide to tannic acid of 1:0.008) was added and reacted at 60 °C for 2 h. After centrifugation at 8000 rpm and drying at 60 °C for 2 h, the dried powder was subjected to corona polarization treatment at 25 °C and 10 kV for 15 min to obtain the modified zinc oxide (the density of surface phenolic hydroxyl groups is 1.5 mmol / g, and the coordination bond binding constant with the coordination crosslinking agent is 10). 5 L / mol); The modified Mxene used in the following examples and comparative examples was prepared by the following method: Mxene (Ti3C2T) x The particle size distribution range is 500-1000 nm, and the thickness is 3 nm (purchased from Aladdin Reagent Co., Ltd.). After being treated with plasma at 100 W under argon for 40 s, it was then subjected to corona polarization under argon at 8 kV for 10 min to obtain the modified Mxene (the hydroxyl content on the surface is 40%). Sodium pyrrolidone carboxylate, PCA-Na, was purchased from Aladdin Reagent Co., Ltd. Fluorosilane coupling agent, 1H,1H,2H,2H-perfluorooctyltriethoxysilane, purchased from Aladdin Reagent Co., Ltd.

[0200] For the remaining raw materials whose purchase sources are not separately listed in this invention, they are all conventional and commonly used components in the field of hydrogel preparation, and their commercially available specifications, key parameters, and usage methods are well known to those skilled in the art. Those skilled in the art can purchase raw materials that meet general industrial standards through conventional channels and, in conjunction with the process parameters disclosed in this invention, stably reproduce the technical solution of this invention. Therefore, no further information on the purchase source, manufacturer, or brand of these raw materials has been added.

[0201] Example 1 This embodiment provides a dual-ring conductive hydrogel brain-computer interface electrode structure and its preparation method. The dual-ring conductive hydrogel brain-computer interface electrode structure includes an inner ring main conductive channel layer and an outer ring secondary dissipation channel layer coaxially arranged; and a modified hydrophilic layer and a modified hydrophobic layer are respectively arranged on both sides along the thickness direction of the dual-ring conductive hydrogel brain-computer interface electrode structure.

[0202] The raw materials for preparing the inner ring main conductive channel layer include, by weight percentage, 10 wt% PVA, 5 wt% PVP, 2 wt% silver nanowires, 3 wt% poly(3,4-ethylenedioxythiophene):polystyrene sulfonate, 1 wt% zinc oxide, 0.5 wt% 1-butyl-3-methylimidazolium tetrafluoroborate, and the balance being water.

[0203] The raw materials for preparing the outer ring secondary dissipation channel layer include, by mass percentage, 6 wt% PVA, 8 wt% GelMA, 3 wt% modified barium titanate, 0.2 wt% ferric chloride, 0.8 wt% tannic acid, 6 wt% segment relaxation regulating component (a composition of low-molecular-weight polyethylene glycol, medium-molecular-weight polyethylene glycol, and high-molecular-weight polyethylene glycol in a mass ratio of 1:1:1) and the balance being water.

[0204] The preparation method includes: (1) PVA, PVP and water were stirred and mixed at 95°C for 45 min. The mixture was cooled to 65°C and silver nanowires, poly(3,4-ethylenedioxythiophene):polystyrene sulfonate and zinc oxide were added and stirred and mixed for 30 min. Then 1-butyl-3-methylimidazolium tetrafluoroborate was added at constant temperature and stirred and mixed for 30 min. The mixture was then degassed under vacuum at -0.1 MPa for 10 min to obtain mixed solution A. PVA, GelMA and water were stirred and mixed at 90℃ for 40 min. The mixture was cooled to 55℃ and modified barium titanate, tannic acid and chain relaxation regulating components were added and mixed for 30 min. Ferric chloride was added at constant temperature and stirred and mixed for 30 min. The mixture was then degassed under vacuum at -0.1 MPa for 10 min to obtain mixed solution B. (2) Inject the mixed solution A into the inner ring (inner ring diameter 7 mm, thickness 3 mm) of the double ring mold and perform pre-crosslinking treatment at -10℃ for 15 min. Then inject the mixed solution B into the outer ring (outer ring diameter 13 mm, thickness 3 mm) of the double ring mold and perform crosslinking treatment at -40℃ for 30 min. (3) Mix sodium pyrrolidone carboxylate with water to prepare a mixed solution C containing 3 wt% sodium pyrrolidone carboxylate; A fluorosilane coupling agent was mixed with water to prepare a mixed solution D containing 2 wt% fluorosilane coupling agent; The hydrogel obtained after crosslinking was immersed in mixed solution C for 10 min on one side and allowed to stand at 25°C for 10 min to complete the hydrophilic modification treatment; then mixed solution D was sprayed on the other side surface and allowed to stand at 25°C for 10 min to complete the hydrophobic modification treatment, thus obtaining the double-ring conductive hydrogel brain-computer interface electrode structure.

[0205] Example 2 This embodiment provides a dual-ring conductive hydrogel brain-computer interface electrode structure and its preparation method. The difference from Embodiment 1 is that the mass percentage of modified barium titanate in the outer ring secondary dissipation channel layer is replaced with modified zinc oxide.

[0206] Example 3 This embodiment provides a dual-ring conductive hydrogel brain-computer interface electrode structure and its preparation method. The difference from Embodiment 1 is that the mass percentage of modified barium titanate in the outer ring secondary dissipation channel layer is replaced with modified MXene.

[0207] Example 4 This embodiment provides a dual-ring conductive hydrogel brain-computer interface electrode structure and its preparation method. The difference from embodiment (1) is that the mixed solution C contains 3 wt% sodium pyrrolidone carboxylate, 0.5 wt% glycerol, 0.2 wt% sodium chloride and the balance water.

[0208] Example 5 This embodiment provides a dual-ring conductive hydrogel brain-computer interface electrode structure and its preparation method. The difference from embodiment (1) is that the raw materials for preparing the outer ring secondary dissipation channel layer include, by mass percentage, 6 wt% PVA, 8 wt% GelMA, 3 wt% modified barium titanate, 0.3 wt% ferric chloride, 1 wt% tannic acid, 6 wt% segment relaxation regulation component (a composition of low-molecular-weight polyethylene glycol, medium-molecular-weight polyethylene glycol and high-molecular-weight polyethylene glycol in a mass ratio of 1:1:1) and the balance being water.

[0209] Comparative Example 1 This comparative example provides a conductive hydrogel structure and its preparation method. The conductive hydrogel structure comprises, by mass percentage, 16 wt% PVA, 5 wt% PVP, 8 wt% GelMA, 2 wt% silver nanowires, 3 wt% poly(3,4-ethylenedioxythiophene):polystyrene sulfonate, 1 wt% zinc oxide, 0.5 wt% 1-butyl-3-methylimidazolium tetrafluoroborate, 3 wt% modified barium titanate, 0.2 wt% ferric chloride, 0.8 wt% tannic acid, 6 wt% segment relaxation modulator (a composition of low-molecular-weight polyethylene glycol, medium-molecular-weight polyethylene glycol, and high-molecular-weight polyethylene glycol in a mass ratio of 1:1:1), and the balance being water.

[0210] (1) PVA, PVP, GelMA and water were stirred and mixed at 95°C for 45 min. The mixture was cooled to 65°C and silver nanowires, poly(3,4-ethylenedioxythiophene): polystyrene sulfonate, zinc oxide, modified barium titanate, tannic acid and chain relaxation regulating components were added and stirred for 30 min. Then, 1-butyl-3-methylimidazolium tetrafluoroborate and ferric chloride were added at a constant temperature and stirred for 30 min. The mixture was then degassed under vacuum at -0.1 MPa for 10 min to obtain a mixed solution. (2) The mixed solution was injected into a single-ring mold (20 mm in diameter) and subjected to freeze crosslinking treatment at -40°C for 30 min; (3) Mix sodium pyrrolidone carboxylate with water to prepare a mixed solution C containing 3 wt% sodium pyrrolidone carboxylate; A fluorosilane coupling agent was mixed with water to prepare a mixed solution D containing 2 wt% fluorosilane coupling agent; The hydrogel obtained after crosslinking was immersed in mixed solution C for 10 min on one side and allowed to stand at 25°C for 10 min to complete the hydrophilic modification treatment; then mixed solution D was sprayed on the other side surface and allowed to stand at 25°C for 10 min to complete the hydrophobic modification treatment, thus obtaining the conductive hydrogel structure.

[0211] Comparative Example 2 This comparative example provides a dual-ring conductive hydrogel brain-computer interface electrode structure and its preparation method. The difference from Example (1) is that the mass percentage of modified barium titanate in the outer ring secondary dissipation channel layer is replaced with unmodified barium titanate (particle size distribution range of 50-200 nm, purchased from Aladdin Reagent Co., Ltd.).

[0212] Comparative Example 3 This comparative example provides a dual-ring conductive hydrogel brain-computer interface electrode structure and its preparation method. The difference from Example (1) is that the outer ring secondary dissipation channel layer does not contain modified barium titanate.

[0213] Test methods (1) Microscopic morphological characterization: The inner ring main conductive channel layer and outer ring secondary dissipation channel layer provided in Example 1 of this invention, as well as the outer ring secondary dissipation channel layers provided in Examples 2, 3, 5, and Comparative Examples 1-3, were each cut into thin sheet-like samples of 5 mm × 5 mm × 0.2 mm. All samples underwent 5-10 nm thick ion sputtering gold conductive treatment, were then fixed on a conductive adhesive sample stage, and their microstructure was characterized using a Zeiss EVO 10 tungsten filament scanning electron microscope under high vacuum conditions (≤1.3 × 10⁻⁶). -4 mbar), with an accelerating voltage of 10 kV and a working distance of 11 mm, imaging was performed using secondary electron SE2 mode. The microstructure results are as follows: Figure 1-8 As shown, the image scale bar is 200 μm.

[0214] As shown in the figures, the inner ring main conductive channel layer provided in Example 1 of this invention has a uniform and interconnected three-dimensional porous network structure with pore sizes distributed in the range of 20-200 μm. The pore walls are smooth and flat, with excellent continuity and no obvious crack defects. The regular and interconnected pore structure provides sufficient and stable conduction channels for ion migration and electron transport within the system, which is the core structural basis for the hydrogel to achieve low-loss signal transmission. The outer ring secondary dissipation channel layers provided in Examples 1-5 all exhibit a regular multi-level porous structure with uniform pore distribution and dense and complete cross-linking of pore walls. The modified nanofiller electret is uniformly attached and dispersed in the pore wall matrix without defects such as agglomeration or stacking. This proves that the modified nanofiller electret has excellent interfacial compatibility with the hydrogel matrix and can fully dissipate low-frequency vibration energy through filler interface slippage and pore structure deformation, giving the material good damping and anti-interference performance.

[0215] In contrast, the outer ring secondary dissipation channel layer provided in Comparative Examples 1-3 has a dense overall matrix structure, a small number of pores, and a disordered arrangement, making it impossible to form a regular multi-level pore network. At the same time, the modified nanofiller electret exhibits significant agglomeration within the system, with numerous interface defects. It lacks a multi-level pore structure that can dissipate energy and a stable filler interface, making it difficult to achieve effective dissipation of vibration energy. Its damping noise reduction and anti-artifact interference performance are far inferior to those of the samples in the embodiments of this invention.

[0216] In summary, this invention achieves functional partitioning of the inner ring for conductivity and the outer ring for dissipation by designing a double-ring layered structure. Combined with the good interfacial compatibility between the modified nanofiller electret and the hydrogel matrix, a multi-level functional network of "conductivity-dissipation separation" is synergistically constructed. This ensures low-loss and high-fidelity transmission of electrophysiological signals while achieving efficient dissipation of low-frequency energy and noise suppression, providing solid microstructural support for the excellent electrochemical sensing performance and dynamic stability monitoring performance of hydrogels.

[0217] (2) Mechanical properties: This invention uses an INSTRON 3365 universal testing machine (speed 1 mm / min, 25℃) to test the mechanical properties of the dual-ring conductive hydrogel brain-computer interface electrode structures (the dual-ring conductive hydrogel brain-computer interface electrode structures were cut into cylindrical hydrogel samples with a diameter of 10 mm and a thickness of 5 mm) provided in Examples 1-5 and Comparative Examples 1-3 of this invention. The compressive stress-compressive strain test graphs are obtained, as shown below. Figure 9As shown in the figure, the samples provided in Examples 1-5 exhibit stable compressive stress within the range of 0.15-0.2 MPa at 50% compressive strain, without significant yielding, demonstrating excellent deformation recovery performance. They possess both superior strength and flexibility, meeting the requirements for dynamic monitoring scenarios. In contrast, the samples provided in Comparative Examples 1-3 show significant fluctuations in compressive stress at 50% strain, indicating poor mechanical stability. Furthermore, the area under the stress-strain curve of the samples provided in Examples 1-5 is significantly larger than that of the samples provided in Comparative Examples 1-3, indicating superior toughness.

[0218] This invention uses an INSTRON 3365 universal testing machine (speed 1 mm / min, 25℃) to test the mechanical properties of the dual-ring conductive hydrogel brain-computer interface electrode structures (the dual-ring conductive hydrogel brain-computer interface electrode structures were cut into cylindrical hydrogel samples with a diameter of 10 mm and a thickness of 5 mm) provided in Examples 1-5 and Comparative Examples 1-3. The slope of the compressive stress-compressive strain test graph in the 10-30% strain range is taken as the compressive modulus. Figure 10 As shown in the figure, the compressive modulus of the samples provided in Examples 1-5 of this invention is distributed in the range of 65±3 kPa to 140±4 kPa, and is generally within the optimal fit range of 80-140 kPa. The modulus values ​​are concentrated and the batch stability is excellent, which can simultaneously meet the requirements of structural deformation resistance and skin-wearing flexibility. Among them, the sample provided in Example 5 has the highest modulus (140±4 kPa) and the strongest structural support; the sample provided in Example 4 has the lowest modulus (65±3 kPa) and the best flexibility and skin fit. The formula can be flexibly adjusted to achieve modulus customization according to different wearing scenarios. In contrast, the samples provided in the comparative examples have a wide range of compressive modulus, distributed in the range of 30±3 kPa to 120±5 kPa, and poor batch stability: the modulus of the sample provided in Comparative Example 3 is only 30±3 kPa, which is insufficient in structural strength and easy to deform, and cannot guarantee the structural stability of long-term monitoring; the modulus of the sample provided in Comparative Example 1 is 50±3 kPa, which is insufficient in deformation resistance and fatigue resistance.

[0219] This invention uses an INSTRON 3365 universal testing machine (speed 1 mm / min, 25℃) to test the fatigue resistance of the double-ring conductive hydrogel provided in Example 1 of this invention. The compressive stress-strain curves were obtained after 47 compression cycles. The stress range was 0-0.2 MPa, and the strain range was 0-50%. Figure 11 As shown in the figure, after 47 cycles of compression, the test curve did not show significant shift, and the residual strain of the sample was less than 5%, indicating that the bicyclic conductive hydrogel possesses excellent structural reversibility and fatigue resistance.

[0220] This invention uses an INSTRON 3365 universal testing machine (speed 1 mm / min, 25℃) to test the fatigue resistance of the double-ring conductive hydrogel (a cylindrical hydrogel sample with a diameter of 10 mm and a thickness of 5 mm cut from the double-ring conductive hydrogel brain-computer interface electrode structure) provided in Example 1 of this invention. The compressive stress-compression time test graph obtained after 47 compression cycles is shown below. Figure 12 As shown in the figure, thanks to the synergistic effect of dynamic bond reversible recombination, multi-level porous structure buffering, and filler interface slippage, the sample provided in Example 1 can effectively dissipate energy and suppress structural damage. After 47 compression cycles, the stress output of the sample is stable, and the stress attenuation is less than 10%, maintaining stable performance under long-term dynamic load.

[0221] In summary, the mechanical test results show that, relying on the dynamic reversible bonds such as hydrogen bonds and coordination bonds, the continuous fracture and reconstruction can occur in conjunction with the energy dissipation mechanism of the modified filler interface slippage. The compressive modulus of the sample provided in this embodiment of the invention is controllable and stable, falling within the reasonable range of 65-140 kPa suitable for skin wear. Under 50% compression, the stress is stable and the toughness is outstanding, which is far superior to the sample provided by the comparative example with inconsistent modulus and weak mechanical strength. After 47 cycles of reciprocating compression, the residual strain of the sample is <5%, the stress decay is <10%, the curve overlap is high, the fatigue resistance and structural recovery performance are excellent, and it can withstand repeated dynamic deformation, meeting the mechanical service conditions for 72 hours of long-term continuous physiological monitoring.

[0222] (3) Electrochemical performance: This invention utilizes a CHI660E electrochemical workstation to test the electrochemical performance of the dual-ring conductive hydrogel brain-computer interface electrode structures provided in Examples 1, 3, and 5, Comparative Example 1, and Comparative Example 3, obtaining cyclic voltammetry (CV) curves. The CV test scan rate was 50 mV / s, and the voltage range was -0.6 to 0.6 V. Figure 13-17 As shown in the figure, the dual-ring conductive hydrogel brain-computer interface electrode structures provided in Embodiments 1, 3, and 5 of this invention exhibit excellent rectangularity of CV curves, higher peak current values, and interface capacitance reaching 20 μF / cm². 2 The above structures exhibit extremely strong charge storage and transport capabilities; while the conductive hydrogel structures and double-ring conductive hydrogel brain-computer interface electrode structures provided in Comparative Examples 1 and 3 show narrow and flat CV curves, significantly lower peak currents, and interface capacitances of less than 5 μF / cm. 2 It has weak interface polarization capability and poor charge response performance.

[0223] This invention utilizes a CHI660E electrochemical workstation to perform electrochemical performance tests on the dual-ring conductive hydrogel brain-computer interface electrode structures provided in Examples 1, 3, and 5, and Comparative Examples 1 and 3, obtaining impedance-frequency test curves (test frequency range 0.01-10 Hz). 6 Hz, excitation voltage of 5 mV), such as Figure 18-22 As shown in the figure, the dual-ring conductive hydrogel brain-computer interface electrode structures provided in Embodiments 1, 3, and 5 of this invention have an impedance ≤ 1 kΩ at a frequency of 10 Hz, and the overall impedance in the low-frequency range of 0.01-1 Hz is low, resulting in minimal signal loss during charge transmission. In contrast, the conductive hydrogel structures and dual-ring conductive hydrogel brain-computer interface electrode structures provided in Comparative Examples 1 and 3 have an impedance greater than 2 kΩ at 10 Hz, with an overall high impedance in the low-frequency range. This makes them susceptible to external interference during signal transmission and prone to signal distortion.

[0224] This invention utilizes a CHI660E electrochemical workstation to perform electrochemical performance tests on the dual-ring conductive hydrogel brain-computer interface electrode structures provided in Examples 1, 3, and 5, and Comparative Examples 1 and 3. The results are obtained from phase angle-frequency curves (test frequency range 0.01-10). 6 Hz, excitation voltage 5 mV), such as Figure 23-27 As shown in the figure, the dual-ring conductive hydrogel brain-computer interface electrode structures provided in Embodiments 1, 3, and 5 of this invention exhibit a stable phase angle of -40° to -60° in the critical low-frequency range of 0.1-10Hz, demonstrating outstanding capacitance characteristics and excellent noise dissipation capabilities. In contrast, the conductive hydrogel structures and dual-ring conductive hydrogel brain-computer interface electrode structures provided in Comparative Examples 1 and 3 have phase angles greater than -20°, with the system primarily exhibiting resistive characteristics and poor damping noise reduction performance.

[0225] In summary, based on the results of cyclic voltammetry, electrochemical impedance spectroscopy, and phase angle frequency characteristics tests, the bicyclic conductive hydrogel prepared in this invention exhibits excellent comprehensive electrochemical performance. The bicyclic conductive hydrogel brain-computer interface electrode structures provided in Examples 1, 3, and 5 possess excellent charge storage and transmission capabilities, low low-frequency impedance, significantly reducing electrophysiological signal transmission loss, significant capacitance characteristics, and outstanding low-frequency damping and noise dissipation capabilities. In contrast, the conductive hydrogel structures and bicyclic conductive hydrogel brain-computer interface electrode structures provided in Comparative Examples 1 and 3 exhibit low interface capacitance, high low-frequency impedance, and phase angle bias resistance characteristics, resulting in weak charge response, easy signal distortion, and poor anti-interference capabilities.

[0226] (4) Electrical signal performance: Test equipment: function signal generator, digital oscilloscope, standard copper electrode sheet, insulation test fixture; test temperature: 25℃. The conductive surface of the inner ring main conductive channel layer of the dual-ring hydrogel brain-computer interface electrode structure under test is bonded to the standard copper input electrode, while the outer ring secondary dissipative channel layer is left unconnected. The other side of the inner ring main conductive channel layer is bonded to the copper output electrode. The signal generator outputs a 100 Hz sinusoidal standard electrical signal with an amplitude of ±1.0V, which is used as the input signal connected to the input electrode. The oscilloscope performs dual-channel synchronous acquisition: channel 1 acquires the original input waveform from the generator, and channel 2 acquires the output waveform after transmission through the dual-ring hydrogel brain-computer interface electrode structure. Figure 28 This is a test diagram of the electrode signal input-output performance of the dual-ring conductive hydrogel brain-computer interface electrode structure provided in Embodiment 1 of the present invention. The voltage range is -1.0~1.0 V, and the time range is -2~2 s. Figure 29 This is a test graph showing the input-output performance of the electrode signal of the dual-ring conductive hydrogel brain-computer interface electrode structure provided in Embodiment 1 of the present invention. The voltage range is -1.0 to 1.0 V, and the time range is -0.04 to 0.04 s. As can be seen from the graph, the output waveform of the dual-ring conductive hydrogel brain-computer interface electrode structure provided in Embodiment 1 of the present invention closely matches the input waveform, with no obvious waveform distortion or signal delay, exhibiting extremely high signal fidelity, and the signal amplitude attenuation is less than 5%, resulting in extremely low signal transmission loss. This excellent signal transmission performance is attributed to the unique inner ring ion-electron hybrid conductive network in the dual-ring conductive hydrogel brain-computer interface electrode structure. The inner ring components synergistically construct an efficient and stable conductive path, which can effectively reduce signal transmission resistance and achieve low-loss, hysteresis-free signal conduction.

[0227] In summary, the dual-ring conductive hydrogel brain-computer interface electrode structure prepared in this invention has the advantages of stable high-frequency signal transmission capability, extremely low waveform attenuation, and no hysteresis transmission. This hydrogel can accurately collect weak high-frequency electrophysiological signals such as EEG, and the collected waveforms are regular, with high signal-to-noise ratio, good multi-channel consistency, and no baseline drift or artifact interference during long-term monitoring.

[0228] (5) Electroencephalogram (EEG) test: This invention, based on internationally accepted EEG electrode layout standards, selects CP2, P8, P4, Pz, P3, P7, CP6, Oz, O1, POz, Fp1, Fp2, Fpz, F7, F3, Fz, F4, F8, FC5, FC1, FC2, FC6, M1, T7, C3, Cz, C4, T8, M2, CP5, and CP1 as multi-channel electrode points for simultaneous EEG signal acquisition, covering the parietal lobe, occipital lobe, and the core brain region at the parietal-central commissure. EEG testing is performed on the dual-ring conductive hydrogel brain-computer interface electrode structure provided in Example 1 of this invention. The 0-150 s long-term test is used to observe baseline stability, baseline drift, and artifact interference. The results are as follows: Figure 30 As shown in the figure, during the continuous acquisition process from 0 to 150 seconds, the baseline of the EEG signal acquired by the hydrogel electrode remained stable, with no obvious baseline drift or clutter artifacts, demonstrating excellent long-term monitoring stability. A 60-70 second local magnification test was used to finely distinguish the characteristic rhythms of alpha waves (8-13 Hz) and beta waves (14-30 Hz), analyze waveform regularity and signal-to-noise ratio, and simultaneously verify the synchronization consistency and spatial resolution of multi-channel signals. The results are as follows... Figure 31 As shown in the figure, the test waveforms are regular and clear, accurately distinguishing the typical EEG characteristic bands of alpha waves (8-13 Hz) and beta waves (14-30 Hz), with an excellent signal-to-noise ratio. Simultaneously, the multi-channel signal acquisition exhibits good consistency, with high synchronization and small numerical differences among channels, demonstrating excellent spatial resolution. This superior EEG acquisition performance is attributed to the low interfacial impedance and good damping characteristics of the hydrogel electrodes, which effectively reduce external interference, suppress motion artifacts, and ensure stable signal output over a long period.

[0229] In summary, the dual-ring conductive hydrogel brain-computer interface electrode structure provided by this invention has low interfacial impedance and good damping characteristics, which can effectively reduce external interference, suppress motion artifacts, and ensure stable signal output over a long period of time. It can achieve high-quality and high-stability EEG signal acquisition, fully meet the application needs of clinical monitoring and scientific research experiments, and has extremely high application value and broad application prospects in the fields of bioelectric sensing and long-term dynamic monitoring of electrophysiological signals.

[0230] The applicant declares that the above description is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Those skilled in the art should understand that any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention fall within the protection and disclosure scope of the present invention.

Claims

1. A dual-ring conductive hydrogel brain-computer interface electrode structure, characterized in that, The dual-ring conductive hydrogel brain-computer interface electrode structure includes an inner ring main conductive channel layer and an outer ring secondary dissipation channel layer arranged coaxially. The raw materials for preparing the inner ring main conductive channel layer include hydrogel matrix A, electronically conductive components, ionicly conductive components, and functional nanoparticles. The raw materials for preparing the outer ring secondary dissipation channel layer include hydrogel matrix B, polarized modified nanofiller electret, coordination crosslinking agent, hydrogen bond enhancer, and segment relaxation regulating component.

2. The dual-ring conductive hydrogel brain-computer interface electrode structure according to claim 1, characterized in that, The raw materials for preparing the inner ring main conductive channel layer also include solvent A; The raw materials for preparing the inner ring main conductive channel layer include, by mass percentage, 11-19 wt% hydrogel matrix A, 1.1-3.5 wt% electronically conductive component, 0.3-0.8 wt% ionicly conductive component, 0.5-2 wt% functional nanoparticles, and 74.7-87.1 wt% solvent A.

3. The dual-ring conductive hydrogel brain-computer interface electrode structure according to claim 2, characterized in that, The hydrogel matrix A includes PVA and PVP; The electronically conductive component includes electronically conductive fillers and electronically conductive polymers; Based on a mass percentage of 100% for the raw materials used in the preparation of the inner ring main conductive channel layer, the raw materials for the preparation of the inner ring main conductive channel layer contain 1-3 wt% electronically conductive filler. Based on a mass percentage of 100% for the raw materials used in the preparation of the inner ring main conductive channel layer, the raw materials for the preparation of the inner ring main conductive channel layer contain 0.1-0.5 wt% electronically conductive polymer. The electronically conductive filler includes any one or a combination of at least two of the following: silver nanowires, carbon nanotubes, graphene, carbon dots, silver nanoparticles, or conductive carbon black. The electronically conductive polymer includes any one or a combination of at least two of the following: poly3,4-ethylenedioxythiophene, polystyrene sulfonate, polyaniline, polypyrrole, or polythiophene derivatives. The ionic conductive component includes an ionic liquid; The ionic liquid includes any one or a combination of at least two of the following: imidazole ionic liquids, pyridine ionic liquids, quaternary ammonium salt ionic liquids, or lithium salt electrolytes. The imidazole ionic liquid includes 1-butyl-3-methylimidazolium tetrafluoroborate; The functional nanoparticles include metal oxide nanoparticles; The metal oxide nanoparticles include any one or a combination of at least two of zinc oxide, titanium dioxide, iron tetroxide, silicon dioxide, aluminum oxide, cerium dioxide, or metal-organic framework materials. The particle size distribution range of the metal oxide nanoparticles is 30-100 nm. Solvent A includes water.

4. The dual-ring conductive hydrogel brain-computer interface electrode structure according to claim 1, characterized in that, The raw materials for preparing the outer ring secondary dissipation channel layer also include solvent B; The raw materials for preparing the outer ring secondary dissipative channel layer include, by mass percentage, 10-18 wt% hydrogel matrix B, 1-5 wt% polarized modified nanofiller electret, 0.1-0.3 wt% coordination crosslinking agent, 0.5-1 wt% hydrogen bond enhancer, 5-8 wt% segment relaxation regulating component, and 67.7-83.4 wt% solvent B.

5. The dual-ring conductive hydrogel brain-computer interface electrode structure according to claim 4, characterized in that, The hydrogel matrix B comprises PVA and GelMA; The polarized modified nanofiller electret includes any one or a combination of at least two of modified barium titanate, modified zinc oxide, modified MXene, or modified carbon nanotubes. The particle size distribution (CV) of the polarized modified nanofiller electret in the outer ring secondary dissipation channel layer is ≤15%; The interfacial binding energy of the modified nanofiller electret in the outer ring secondary dissipation channel layer is 50-100 mJ / m. 2 ; The coordination crosslinking agent includes any one or a combination of at least two of the following: trivalent aluminum salt, divalent copper salt, divalent zinc salt, trivalent chromium salt, divalent cobalt salt, or divalent nickel salt; The hydrogen bond enhancer includes any one or a combination of at least two of the following: tannic acid, citric acid, gallic acid, polydopamine, dopamine, tannic acid derivatives, or ethylene glycol. The segment relaxation regulating component includes any one or at least two of the following: a combination of polyethylene glycols of different molecular weights, a combination of polypropylene glycols of different molecular weights, or a combination of polyols of different molecular weights. The combination of polyethylene glycols with different molecular weights includes combinations of low-molecular-weight polyethylene glycol, medium-molecular-weight polyethylene glycol, and high-molecular-weight polyethylene glycol; The number-average molecular weight of the oligomeric polyethylene glycol is 800-1200 g / mol; The number-average molecular weight of the polyethylene glycol in the medium is 8000-12000 g / mol; The number-average molecular weight of the high-polymer polyethylene glycol is 80,000-120,000 g / mol; The mass ratio of the oligomeric polyethylene glycol, medium-polymer polyethylene glycol, and high-polymer polyethylene glycol is 1:(0.8-1.2):(0.8-1.2). Solvent B includes water; The raw materials for preparing the modified barium titanate include barium titanate and silane coupling agent; The mass ratio of barium titanate to silane coupling agent is 1:(0.01-0.03). The particle size distribution range of the barium titanate is 50-200 nm. The silane coupling agent includes γ-methacryloxypropyltrimethoxysilane; The modified barium titanate was subjected to thermal polarization treatment; The double bond density on the surface of the modified barium titanate is 0.5-1.0 mmol / g; The covalent bond rate between the modified barium titanate and GelMA is ≥80%; The raw materials for preparing the modified zinc oxide include zinc oxide and tannic acid; The particle size distribution range of the zinc oxide is 30-100 nm; The mass ratio of zinc oxide to tannic acid is 1:(0.005-0.01). The modified zinc oxide is subjected to corona polarization treatment; The density of surface phenolic hydroxyl groups in the modified zinc oxide is 1.0-2.0 mmol / g; The coordination bond constant between the modified zinc oxide and the coordination crosslinking agent is ≥10. 5 L / mol; The modified MXene is prepared by the following method, which includes: The modified MXene was obtained by subjecting MXene to plasma treatment and corona polarization treatment. The MXene has a sheet size distribution range of 500-1000 nm; The thickness of the MXene is 1-5 nm; The plasma treatment and the corona polarization treatment are each performed independently in an inert gas atmosphere; The inert gas includes argon; The power of the plasma treatment is 80-120 W; The plasma treatment time is 30-60 s; The voltage for the corona polarization treatment is 7-10 kV; The corona polarization treatment time is 8-15 min; The modified MXene has a surface hydroxyl terminator site ratio of 30-50%; The raw materials for preparing the modified carbon nanotubes include carbon nanotubes and polyethylene glycol; The mass ratio of carbon nanotubes to polyethylene glycol is 1:(8-12). The diameter of the carbon nanotubes is 5-20 nm; The length of the carbon nanotubes is 100-500 nm; The number-average molecular weight of the polyethylene glycol is 1800-2200 g / mol; The modified carbon nanotubes are subjected to thermal polarization treatment; The surface grafting rate of the modified carbon nanotubes is 30-50%.

6. The dual-ring conductive hydrogel brain-computer interface electrode structure according to claim 1, characterized in that, The diameter of the inner ring main conductive channel layer is 5-8 mm; The outer diameter of the outer ring secondary dissipation channel layer is 10-15 mm; The thickness of the dual-ring conductive hydrogel brain-computer interface electrode structure is 3-10 mm. The dual-ring conductive hydrogel brain-computer interface electrode structure has an asymmetric interface functional layer along the thickness direction.

7. The dual-ring conductive hydrogel brain-computer interface electrode structure according to claim 6, characterized in that, The asymmetric interface functional layer includes a modified hydrophilic layer and a modified hydrophobic layer respectively disposed on both sides along the thickness direction of the double-ring conductive hydrogel brain-computer interface electrode structure. The modified hydrophilic layer comprises, by mass percentage, 1-5 wt% hydrophilic agent, 0-1 wt% humectant, 0-0.5 wt% electrolyte, and 95-98% solvent C; The hydrophilic agent includes sodium pyrrolidone carboxylate; The humectant includes glycerin; The electrolyte includes sodium chloride; The solvent C includes water; The modified hydrophobic layer comprises, by mass percentage, 1-5 wt% fluorosilane coupling agent and 95-99% solvent D; The solvent D includes water; The fluorosilane coupling agent includes long-chain perfluoroalkyl silanes; The long-chain perfluoroalkylsilanes include any one or a combination of at least two of 1H,1H,2H,2H-perfluorooctyltriethoxysilane, 1H,1H,2H,2H-perfluorodecyltrimethoxysilane, or 1H,1H,2H,2H-perfluorodecyltriethoxysilane.

8. A method for preparing a dual-ring conductive hydrogel brain-computer interface electrode structure as described in any one of claims 1-7, characterized in that, The preparation method includes the following steps: (1) Mix the raw materials for preparing the inner ring main conductive channel layer to obtain mixed solution A; The raw materials for preparing the outer ring secondary dissipation channel layer were mixed to obtain mixed solution B; (2) Inject the mixed solution A into the inner ring of the double-ring mold for pre-crosslinking treatment, and then inject the mixed solution B into the outer ring of the double-ring mold for crosslinking treatment to obtain the double-ring conductive hydrogel brain-computer interface electrode structure.

9. The method for preparing the dual-ring conductive hydrogel brain-computer interface electrode structure according to claim 8, characterized in that, The mixing of raw materials for the preparation of the inner ring main conductive channel layer in step (1) includes a first stage mixing, a second stage mixing, and a third stage mixing; The first stage of mixing includes mixing hydrogel matrix A and solvent A; The second stage of mixing includes mixing the mixture obtained after the first stage of mixing with electronically conductive components and functional nanoparticles; The third stage mixing includes mixing the mixture obtained after the second stage mixing with the ion-conducting component; The mixing temperature in the first stage is 90-100℃, and the time is 30-60 min; The mixing temperature in the second stage is 60-70℃, and the time is 20-40 min; The mixing temperature in the third stage is 60-70℃, and the time is 20-40 min; The third stage of mixing also includes a vacuum degassing step; The vacuum degree of the vacuum degassing after the third stage of mixing is -0.05~-0.1 MPa, and the time is 5-15 min; The mixing of raw materials for the preparation of the outer ring secondary dissipation channel layer in step (1) includes a first mixing, a second mixing, and a third mixing; The first mixing includes mixing the hydrogel matrix B and solvent B; The second mixing includes mixing the mixture obtained after the first mixing with the modified nanofiller electret, hydrogen bond enhancer and segment relaxation regulating component; The third mixing includes mixing the mixture obtained after the second mixing with a coordination crosslinking agent; The temperature for the first mixing is 85-90℃, and the time is 35-45 min; The second mixing is performed at a temperature of 50-60℃ for 20-40 minutes. The third mixing is performed at a temperature of 50-60℃ for 20-40 minutes. The third mixing process also includes a vacuum degassing step; The vacuum degree of the third mixing and degassing is -0.05 to -0.1 MPa, and the time is 5-15 min; The temperature for the pre-crosslinking treatment in step (2) is -15~-5℃, and the time is 10-20 min; The crosslinking treatment in step (2) is performed at a temperature of -45 to -35°C for 25 to 35 minutes. The preparation method further includes performing hydrophilic modification and hydrophobic modification treatments on both sides of the cross-linked hydrogel in step (2) along the thickness direction. The hydrophilic modification treatment includes the following steps: The components of the modified hydrophilic layer are mixed to obtain a mixed solution C; One side of the hydrogel is immersed in mixed solution C to complete the hydrophilic modification treatment; The immersion time is 10-15 minutes; The impregnation process also includes standing at 20-30°C for 10-30 minutes. The hydrophobic modification treatment includes the following steps: The components of the modified hydrophobic layer are mixed to obtain a mixed solution D; The hydrophobic modification treatment is completed by spraying the mixed solution D onto the other side surface of the hydrogel. The process after spraying also includes allowing the product to stand at 20-30℃ for 10-30 minutes.

10. The application of a dual-ring conductive hydrogel brain-computer interface electrode structure as described in any one of claims 1-7 in an electrophysiological signal acquisition system.

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