A silicone rubber based brain-machine dry electrode material using zinc dimethacrylate to improve the dispersion of conductive fillers

Abstract

The application belongs to the technical field of electroencephalogram signal detection, and provides a silicone rubber-based brain-machine dry electrode material for improving the dispersibility of conductive fillers by adopting zinc dimethyl acrylate; the electrode uses zinc dimethyl acrylate as a dispersant for conductive fillers in the electrode; silicone rubber is used as the main body in the electrode material, and conductive fillers such as conductive carbon black, carbon nanotubes, graphene and silver particles are added to form effective paths. In the brain-machine interface electrode material, the dry electrode has the advantages of long-term use and reusability compared with the wet electrode and the semi-dry electrode, but has the disadvantages of poor conductivity and high contact impedance. In order to increase the conductivity of the dry electrode, more conductive fillers are added, and the agglomeration problem caused by excessive content of the conductive fillers reduces the conductivity of the dry electrode material and makes the molding difficult. The zinc dimethyl acrylate added in the application solves the agglomeration problem of the conductive fillers, makes the conductive fillers uniformly dispersed in the silicone rubber substrate, increases the conductivity of the electrode, and better collects the electroencephalogram signal.

Description

A silicone rubber-based brain-computer interface dry electrode material with zinc dimethacrylate to improve the dispersion of conductive fillers Technical Field

[0001] This invention belongs to the field of electroencephalogram (EEG) signal detection technology, specifically relating to a silicone rubber-based brain-computer interface dry electrode material that uses zinc dimethacrylate to improve the dispersion of conductive fillers. Background Technology

[0002] Brain-computer interface (BCI) technology, as a novel form of human-computer interaction, collects bioelectrical signals from the brain and its activities using various electrodes in the cerebral cortex, enabling the monitoring and feedback of these signals. Before use, wet and semi-dry electrode systems require the injection of conductive paste or gel into the electrodes. During recording, the gel dries over time. These processes are time-consuming, unsuitable for long-term monitoring, and can lead to an uncomfortable user experience. Therefore, flexible polymer dry electrodes have been widely used and researched.

[0003] In the field of brain-computer interfaces, flexible polymer dry electrodes for EEG signal acquisition are mainly composed of flexible polymers and conductive fillers. Currently, the fabrication of dry electrodes faces the following main problems: 1. Lack of good adhesion and interaction between the conductive filler and the polymer; 2. Increased conductive filler content makes polymer molding difficult and results in uneven particle dispersion, ultimately leading to poor material performance consistency. (See "Liliane Bokobza, Multiwall carbon nanotube elastomeric composites: A review, Polymer, Volume 48, Issue 17, 2007, Pages 4907-4920, ISSN0032-3861" and "Du Jian. Research on Flexible Micro / Nano Stress Sensors Based on CNT-PDMS Composite Materials [D]; Qilu University of Technology, 2020.") Therefore, the dispersion of conductive fillers in the polymer is particularly important for signal acquisition and requires focused research. Summary of the Invention

[0004] To address the problems of uneven dispersion of conductive fillers and unstable signals in existing dry electrodes, this invention provides a silicone rubber EEG dry electrode with zinc dimethacrylate to improve the dispersion of conductive fillers, enabling the conductive fillers to form a uniform conductive network within the silicone rubber. This silicone rubber-based EEG dry electrode material exhibits good mechanical properties and biocompatibility, and its advantages include strong conductivity and good signal acquisition stability.

[0005] The technical solution of this invention:

[0006] A silicone rubber-based brain-computer interface dry electrode material with improved conductive filler dispersion using zinc dimethacrylate is mainly prepared by mixing flexible silicone rubber, conductive filler and zinc dimethacrylate. The conductive filler is dispersed in the flexible silicone rubber to form a conductive path. The addition of zinc dimethacrylate makes the conductive network more uniform and stable. After physical mixing and high-temperature curing, a silicone rubber-based brain-computer interface dry electrode material with good conductive filler dispersion is prepared.

[0007] The zinc dimethacrylate can be grafted and polymerized into rubber chains as an active crosslinking agent to form a crosslinked network, improving the mechanical properties of the rubber. Simultaneously, the conductive filler is more uniformly dispersed in the rubber and zinc dimethacrylate matrix, enhancing its adhesion to the rubber. The preparation of silicone rubber EEG dry electrode materials using zinc dimethacrylate to improve the dispersion of conductive fillers requires an organic solvent; dissolving the silicone rubber increases the dispersion range of the conductive filler within it.

[0008] Preferably, the silicone rubber component is polydimethylsiloxane, which is cured at high temperature in a certain proportion with its corresponding curing agent, and has the advantages of good biocompatibility and relatively stable properties.

[0009] Preferably, the polydimethylsiloxane is dissolved in an organic solvent, and the conductive filler is dispersed in the solvent. The organic solvent is selected as n-hexane.

[0010] Preferably, the selected conductive filler includes, but is not limited to, highly conductive conductive carbon black, carbon nanotubes, graphene, silver particles, etc.

[0011] Preferably, the zinc dimethacrylate is used as a conductive filler dispersant, and its added mass is 10% to 20% of the mass of polydimethylsiloxane.

[0012] Preferably, the organic solvent is evaporated before the polydimethylsiloxane curing agent is added for curing.

[0013] The beneficial effects of this application are as follows: This application provides a silicone rubber-based brain-computer interface dry electrode material with zinc dimethacrylate to improve the dispersibility of conductive fillers. The electrode material uses flexible silicone rubber as the main body, and conductive fillers and conductive filler dispersants are added to the electrode while being mixed in an organic solvent. The electrode material itself is flexible and has a good conductive network. The addition of zinc dimethacrylate improves the conductivity and stability of the electrode material, resulting in a better detection signal. Attached Figure Description

[0014] Figure 1 is a microstructure diagram of the silicone rubber-based brain-computer interface dry electrode with zinc dimethacrylate to improve the dispersibility of conductive fillers according to the present invention.

[0015] Figure 2 is a schematic diagram of the structure of the silicone rubber-based brain-computer interface dry electrode with zinc dimethacrylate to improve the dispersibility of conductive fillers according to the present invention.

[0016] Figure 3 shows the compression curve of the silicone rubber-based brain-computer interface dry electrode material with improved conductive filler dispersion by zinc dimethacrylate according to the present invention. Detailed Implementation

[0017] The technical solutions of the embodiments of the present invention will be described in detail below with reference to the accompanying drawings. The described embodiments are merely some, not all, of the embodiments of the present invention. It should be noted that all other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0018] This example provides a silicone rubber-based brain-computer interface dry electrode material with zinc dimethacrylate to improve the dispersion of conductive fillers. The electrode material includes flexible silicone rubber and conductive fillers and their dispersants, wherein the conductive fillers are dispersed in the silicone rubber to form a conductive network.

[0019] In this embodiment, the flexible silicone rubber is polydimethylsiloxane, which is mixed with a curing agent at a mass ratio of 10:1. The selected material has stable chemical properties, strong thermal stability, good transparency and biocompatibility. It can be customized to fit the scalp well through surface modification and overall characteristics, making it more comfortable and safe to wear.

[0020] In this embodiment, the selected organic solvent is n-hexane, which can dissolve PDMS and disperse the conductive filler in PDMS in the solvent.

[0021] In this embodiment, the selected conductive particles are carbon nanotubes, which have good conductivity, mature preparation process, and are conducive to industrial production. They form a stable electrode interior and a smooth electrode surface, and are used to make conductive silicone rubber electrodes for collecting EEG signals from the hair area.

[0022] In this embodiment, the selected carbon nanotube dispersant is zinc dimethacrylate, which is polymerized into silicone rubber as a crosslinking agent. Zinc dimethacrylate is used to block the aggregation of carbon nanotubes to prevent the aggregation of carbon nanotubes, thereby uniformly dispersing the carbon nanotubes in PDMS and reducing the resistivity of the electrode.

[0023] In this embodiment, the specific steps for fabricating the silicone rubber-based brain-computer interface dry electrode material with zinc dimethacrylate to improve the dispersion of carbon nanotubes are as follows:

[0024] Add PDMS to n-hexane, dissolve 1g of PDMS in every 5mL of n-hexane, and sonicate for 5min to completely dissolve the PDMS.

[0025] Add 20 wt% carbon nanotubes and stir magnetically to disperse the carbon nanotubes in the solution;

[0026] Add 15 wt% zinc dimethacrylate to the solution and continue magnetic stirring;

[0027] Place the dispersed solution in a 70℃ oven and evaporate for 1 hour until dry.

[0028] Add PDMS curing agent at a mass ratio of 10:1 and mechanically stir until homogeneous;

[0029] The mixed material is filled into a mold and placed in a vacuum pump for vacuum treatment;

[0030] After vacuum curing, the mold was placed in an oven at 80°C for 2 hours to obtain a silicone rubber-based brain-computer interface dry electrode material with improved carbon nanotube dispersion by zinc dimethacrylate.

[0031] In this embodiment, Figure 1 is a microstructure diagram of a silicone rubber-based brain-computer interface dry electrode with zinc dimethacrylate to improve the dispersion of carbon nanotubes. The polymerization force between silicone rubber and zinc dimethacrylate weakens the aggregation of carbon nanotubes, allowing the carbon nanotubes to be uniformly dispersed in the silicone rubber.

[0032] In this embodiment, Figure 2 is a schematic diagram of the structure of the silicone rubber-based brain-computer interface dry electrode using zinc dimethacrylate to improve the dispersion of carbon nanotubes. To reduce interference from hair on signal acquisition, a three-claw electrode is selected, with its downward-protruding electrode post being conical, facilitating contact with the scalp and ensuring safety and comfort.

[0033] In this embodiment, Figure 3 shows the compression stress-strain curves of three samples of silicone rubber-based brain-computer interface dry electrode material with zinc dimethacrylate to improve the dispersion of carbon nanotubes. The maximum deformation of the material is about 37%, the compressive strength is 0.65 MPa, the elastic modulus is within the acceptable range for the scalp and does not damage the scalp, and it can be reused.

[0034] In this embodiment, the surface resistivity of the electrode body is 0.08 Ω·m. This effectively reduces the surface contact impedance of the electrode material to achieve better measurement results.

[0035] The above description is merely an example of the present invention and is described in detail, but it does not limit the present invention. Modifications, equivalent substitutions, and improvements can be made within the scope of the present invention.

Claims

1. A silicone rubber-based brain-computer interface dry electrode material using zinc dimethacrylate to improve the dispersion of conductive fillers, characterized in that, The silicone rubber-based brain-computer interface dry electrode material is mainly prepared by mixing flexible silicone rubber, conductive filler and zinc dimethacrylate. The conductive filler is dispersed in the flexible silicone rubber to form a conductive path. The addition of zinc dimethacrylate makes the conductive network more uniform and stable. After physical mixing and high-temperature curing, the silicone rubber-based brain-computer interface dry electrode material is obtained. The flexible silicone rubber is dissolved in an organic solvent, the conductive filler is dispersed in the organic solvent, and after the organic solvent evaporates, a flexible silicone rubber curing agent is added for curing.

2. The silicone rubber-based brain-computer interface dry electrode material according to claim 1, characterized in that, The zinc dimethacrylate is used as a conductive filler dispersant, and its added mass is 10% to 20% of the mass of the flexible silicone rubber.

3. The silicone rubber-based brain-computer interface dry electrode material according to claim 1, characterized in that, The flexible silicone rubber is composed of polydimethylsiloxane, which is cured at high temperature in proportion to its corresponding curing agent.

4. The silicone rubber-based brain-computer interface dry electrode material according to claim 1, characterized in that, The conductive filler includes conductive carbon black, carbon nanotubes, graphene, and silver particles.

5. The silicone rubber-based brain-computer interface dry electrode material according to claim 1, characterized in that, The organic solvent is n-hexane.

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