A method for encapsulating fiber electrodes

Abstract

This application relates to the field of biointerface sensing technology, and particularly to a method for encapsulating fiber electrodes, comprising: preparing a PET mask template with a preset pattern; placing the PET mask template with the preset pattern on the water surface where an SEBS film is formed to obtain a mask template with a nanoscale SEBS film; sandwiching conductive fibers with two mask templates with nanoscale SEBS films from the top and bottom respectively to construct a sandwich encapsulation structure; gradually peeling the SEBS film off the PET mask template; and removing the encapsulated conductive fibers as a whole from the two mask templates with nanoscale SEBS films to obtain a stretchable conductive fiber structure with localized insulating coating and functional exposure windows. This application can achieve effective insulation protection for the non-functional areas of the conductive fibers, while retaining exposed conductive interfaces in the monitoring area to meet their functional requirements during electrophysiological signal acquisition, and effectively preventing environmental corrosion of the non-functional areas.

Description

Technical Field

[0001] This application relates to the field of biointerface sensing technology, and in particular to a method for encapsulating a fiber electrode. Background Technology

[0002] With the rapid development of wearable medical devices, human-computer interaction, and remote health monitoring, traditional rigid electrodes are increasingly unable to meet the demands for flexibility, comfort, and dynamic conformability. In contrast, flexible, stretchable conductive fibers, with their softness, stretchability, and low impedance, demonstrate significant advantages in next-generation electrophysiological systems. These conductive fibers can not only be woven into or adhered to the skin surface for biosignal acquisition but are also suitable for certain implantable physiological interface scenarios, showing promising application prospects.

[0003] Flexible conductive fibers typically have a linear, integral conductive structure, with the entire fiber capable of conducting current. However, while this characteristic provides excellent signal transmission capabilities, it also presents some challenges. For example, when constructing multi-channel electrode arrays or laying out complex signal acquisition paths, it's not necessary for the entire fiber to remain conductive and exposed. Instead, conductive areas should only be maintained near the designated electrode "monitoring points," while the remaining portion requires effective insulation to ensure isolation between channels, accurate localization of electrophysiological signals, and long-term stability of the overall system.

[0004] However, there is currently a lack of an efficient and selective encapsulation method for integral conductive fiber electrodes that can simultaneously meet the technical requirements of precise exposure of the monitoring area and selective insulation encapsulation of the non-monitoring area. Summary of the Invention

[0005] This application provides a method for encapsulating a fiber electrode, which can effectively insulate and protect the non-functional areas of the conductive fiber while retaining the exposed conductive interface in the monitoring area to meet its functional requirements during electrophysiological signal acquisition and effectively prevent environmental corrosion of the non-functional areas.

[0006] To address the aforementioned technical problems, this application provides a method for encapsulating a fiber electrode, comprising the following steps: First, a PET mask template with a preset pattern is prepared; the PET mask template has an open area, which can be used to restrict the local forming of a nanoscale thin film; then, the PET mask template with the preset pattern is placed on the water surface where the SEBS film is formed, so that the open area of ​​the PET mask template is in full contact with the SEBS film, ensuring that the SEBS film is firmly attached to the pattern area of ​​the PET mask template, thus obtaining a mask template with a nanoscale SEBS film; next, two mask templates with nanoscale SEBS films are sandwiched and wrapped around conductive fibers from the top and bottom sides respectively, utilizing the self-adhesiveness of the SEBS film to achieve stable adhesion between the film and the conductive fibers, thus constructing a sandwich encapsulation structure; subsequently, the SEBS film is gradually peeled off from the PET mask template, so that the film is firmly attached to the surface of the conductive fiber and gradually detaches from the mask template; finally, the encapsulated conductive fiber is completely removed from the two mask templates with nanoscale SEBS films, resulting in a stretchable conductive fiber structure with local insulating coating and functional exposure windows.

[0007] In some exemplary embodiments, the preparation of a PET mask template with a preset pattern includes: positioning the exposed areas on the conductive fibers according to the functional design of the conductive fibers to be encapsulated; drawing a pattern of the mask template according to the position, size, and shape of the exposed areas on the conductive fibers, for subsequent determination of the patterned forming area of ​​the nanoscale SEBS film; importing the pattern of the mask template into an ultraviolet laser marking system, and performing high-precision pattern cutting on a high-transparency PET film using an ultraviolet laser marking machine to obtain a PET mask template with a preset pattern.

[0008] In some exemplary embodiments, the water surface on which the SEBS film is formed includes: preparing a clean culture dish that matches the packaging size and filling it with deionized water to ensure that the water surface is flat, free of bubbles and impurities; adding a 5%-20% mass fraction SEBS toluene solution to the central area of ​​the culture dish containing clean water, and the solution rapidly spreading on the water surface to form a stable nanofilm.

[0009] In some exemplary embodiments, the SEBS film is a styrene-ethylene-butene-styrene block copolymer film.

[0010] In some exemplary embodiments, after adding SEBS toluene solution and letting it stand for 10 seconds, a transparent, continuous nanofilm can be formed on the water surface, with a thickness of 50 nm to 200 nm.

[0011] In some exemplary embodiments, the preparation of a mask template with a nanoscale SEBS film includes: after placing a PET mask template with a preset pattern on the surface of water where the SEBS film is formed, using tweezers to remove the SEBS film from the excess area outside the PET mask template, ensuring that the SEBS film layer is retained only in the desired opening area, thereby obtaining a mask template with the patterned area covered by a nanoscale SEBS film to achieve functional coating of local areas of conductive fibers.

[0012] In some exemplary embodiments, two mask templates with nanoscale SEBS films are sandwiched around conductive fibers from the top and bottom, respectively. The self-adhesive properties of the SEBS film are used to achieve a stable bond between the film and the conductive fibers, thus constructing a sandwich encapsulation structure. This includes: using two mask templates with nanoscale SEBS films as the upper and lower layers of the encapsulation, respectively; laying the conductive fibers flat on the SEBS film surface of the lower mask template, ensuring that the target exposed area of ​​the conductive fibers is accurately aligned with the pattern opening on the mask template during positioning; and then aligning the upper mask template with the lower mask template from above and covering the conductive fibers, so that the conductive fibers are located between the two SEBS films, thus constructing a sandwich encapsulation structure.

[0013] In some exemplary embodiments, the SEBS film is gradually peeled off from the PET mask template to firmly attach the film to the conductive fiber surface and gradually detach from the mask template, including: after the film and conductive fiber are bonded together, using tweezers and scissors to gently peel the SEBS film off from the PET mask template along the edge of the SEBS film on the mask template to firmly attach the film to the conductive fiber surface and gradually detach from the PET mask template.

[0014] In some exemplary embodiments, the encapsulation material in the sandwich encapsulation structure is a nano-thickness thin film material with good biocompatibility and good insulation.

[0015] In some exemplary embodiments, in a stretchable conductive fiber structure having partial insulation covering and functional exposure windows, the surface area of ​​the conductive fiber is covered with a highly flexible, highly elastic and biocompatible SEBS film, and functional exposure windows are reserved only in pre-defined opening areas to realize the functions of electrode contact, electrical signal acquisition or electrical stimulation output.

[0016] The technical solution provided in this application has at least the following advantages:

[0017] This application provides a method for encapsulating a fiber electrode, comprising the following steps: First, a PET mask template with a preset pattern is prepared; the PET mask template has an opening area, which can be used to restrict the local forming of a nanoscale thin film; then, the PET mask template with the preset pattern is placed on the water surface where the SEBS film is formed, so that the opening area of ​​the PET mask template is in full contact with the SEBS film, ensuring that the SEBS film is firmly attached to the pattern area of ​​the PET mask template, thus obtaining a mask template with a nanoscale SEBS film; next, two mask templates with nanoscale SEBS films are sandwiched and wrapped around conductive fibers from the top and bottom sides respectively, utilizing the self-adhesiveness of the SEBS film to achieve stable adhesion between the film and the conductive fibers, thus constructing a sandwich encapsulation structure; subsequently, the SEBS film is gradually peeled off from the PET mask template, so that the film is firmly attached to the surface of the conductive fiber and gradually detaches from the mask template; finally, the encapsulated conductive fiber is completely removed from the two mask templates with nanoscale SEBS films, resulting in a stretchable conductive fiber structure with local insulating coating and functional exposure windows.

[0018] This application provides a method for encapsulating fiber electrodes. This method utilizes a customized mask template to prepare a nanoscale elastic insulating SEBS (styrene-ethylene-butene-styrene block copolymer) film, and achieves selective insulating encapsulation of non-exposed areas through a double-layer film covering structure. The encapsulation method proposed in this application achieves precise definition and effective protection of the functional regions of flexible conductive fibers, reaching the technical goals of structural flexibility, conductive stability, simple process, and strong adaptability. It has good application prospects and promotional value, and is particularly suitable for wearable, implantable, and other electrophysiological systems with high requirements for structural flexibility and insulation reliability. Attached Figure Description

[0019] One or more embodiments are illustrated by way of example with reference to the accompanying drawings. These illustrations do not constitute a limitation on the embodiments, and unless otherwise stated, the figures in the drawings are not to be limited by scale.

[0020] Figure 1 This is a schematic flowchart illustrating a method for encapsulating a fiber electrode according to an embodiment of this application.

[0021] Figure 2 This is a schematic diagram of four different shaped mask designs for encapsulation provided in one embodiment of this application.

[0022] Figure 3 This is a schematic diagram of a sandwich-type packaging structure provided in an embodiment of this application. Detailed Implementation

[0023] As can be seen from the background technology, there is currently a lack of an efficient and selective encapsulation method for integral conductive fiber electrodes that can simultaneously meet the technical requirements of precise exposure of the monitoring area and selective insulation encapsulation of the non-monitoring area.

[0024] In the field of electrophysiological signal monitoring, such as electroencephalography (EEG), electrocardiography (ECG), electromyography (EMG), and neural signal recording, electrode performance plays a decisive role in signal quality. In recent years, the rapid development of flexible wearable electronics technology has driven research into fiber-based electrode systems. Fiber electrodes are small in size and possess good flexibility and stretchability, making them one of the future directions for electrode development. However, in practical applications, electrode systems constructed from conductive fibers do not require continuous conductivity throughout. Instead, to ensure spatial resolution and channel independence, it is necessary to maintain conductivity only in specific areas (such as "monitoring points" in contact with tissue), while the remaining parts must be effectively insulated to prevent signal crosstalk, environmental interference, and reliability and durability issues.

[0025] Specifically, signal crosstalk refers to the issue that when multiple fiber electrodes are used close to each other or interleaved, if all of them are conductive, crosstalk or artifact signals are easily generated, affecting the accuracy and repeatability of electrophysiological data. Environmental interference refers to the susceptibility of uninsulated areas to external electric fields, electromagnetic waves, or humidity changes, leading to baseline drift and increased noise. Reliability and durability issues refer to the susceptibility of exposed conductive areas to friction, oxidation, or mechanical damage, reducing electrode lifespan.

[0026] Currently, in the field of flexible conductive fiber encapsulation and patterning, several mature technologies have been applied to wearable electronic devices, implantable electrodes, and flexible sensing systems. These mainly include the following methods:

[0027] 1. Overall coating and impregnation encapsulation technology.

[0028] The technical principle of this method is to immerse the conductive fiber entirely in liquid elastomers such as PDMS, PU, ​​and silicone, or to form a coating layer on its surface by scraping or dripping, followed by room temperature or heating curing. This method usually involves directly immersing the conductive fiber in liquid elastomers (such as PDMS, PU, ​​Ecoflex, etc.), or using scraping, spin coating, spraying, etc., to form a complete coating layer on its surface. After curing, it can provide good flexibility and insulation properties, suitable for large-area continuous encapsulation needs. The disadvantages of this method are: (1) lack of pattern selectivity, unable to control the specific exposed area, all conductive parts are covered; (2) large coating thickness, significantly increasing the fiber diameter, reducing flexibility and tensile properties; (3) coating quality is easily affected by bubbles and flowability, and the process stability is poor; (4) long curing time, making it difficult to meet the needs of large-scale rapid preparation.

[0029] 2. Thermal bonding film layer encapsulation technology (such as TPU film hot pressing method).

[0030] The technical principle of this method is as follows: conductive fibers are sandwiched between two thermoplastic films (such as TPU), and the films are melted and bonded together under heating conditions by a hot pressing device to form an encapsulation structure. This method usually uses thermoplastic elastomer films (such as TPU, PET / EVA, etc.) to sandwich the conductive fibers for hot pressing encapsulation. This type of method utilizes the adhesion of the film under heating conditions to achieve the fusion and bonding of the upper and lower encapsulation films, which is suitable for the encapsulation structure design of high-strength flexible electronic devices. Technical principle: However, this method also has some disadvantages: (1) The encapsulation process requires high temperature and pressure, which may damage temperature-sensitive conductive materials (such as liquid metal composite fibers); (2) The hot pressing equipment is expensive and complicated to operate, which is not suitable for low-cost preparation in the laboratory; (3) The film thickness is generally more than tens of micrometers, which is not conducive to bonding to highly flexible scenarios such as skin; (4) The hot pressing area is difficult to align and control precisely, which can easily cause window position errors.

[0031] 3. Photopolymer patterning encapsulation technology (such as PEGDA or SU-8 method).

[0032] The technical principle of this method is as follows: a photosensitive polymer is coated on the surface of a conductive fiber, and local exposure and patterned curing are achieved by mask illumination, thereby forming a structured encapsulation layer. This method is usually based on the regional exposure and development of photosensitive polymers (such as PEGDA, SU-8, etc.) to achieve patterned coating on conductive fibers. It is often combined with a mask and an ultraviolet exposure system, and can be used to construct functional windows or insulating patterns with micron-scale precision. The disadvantages of this method are: (1) the photoinitiator and biotoxicity issues limit its promotion in skin bonding or biological applications; (2) the cured film has poor mechanical properties and is prone to cracking or falling off after long-term bending; (3) the ultraviolet light source, alignment system, and mask design requirements are high, the process window is narrow, which is not conducive to promotion; (4) the coating step is not easy to control the thickness, and it is difficult to achieve nanoscale ultrathin structures.

[0033] 4. Microfluidic encapsulation (e.g., controllable injection colloid coating)

[0034] The technical principle of this method is as follows: using microfluidics or controlled dripping, liquid encapsulation material is quantitatively injected into a preset channel or mold to form a local encapsulation effect. This technology uses precision control equipment such as microfluidic chips and injection pumps to guide the liquid encapsulation material to the preset encapsulation area. It is suitable for flexible electronic or microsystem encapsulation scenarios where precise control of the encapsulation position and shape is required. The disadvantages are: (1) the process relies on a complex fluid control system, and the equipment is expensive; (2) it is difficult to achieve large-area, continuous encapsulation; (3) the mold design is complex and the structural change flexibility is poor.

[0035] Therefore, there is currently a lack of an efficient and selective encapsulation method for integral conductive fiber electrodes that can simultaneously meet the following technical requirements: (1) selective insulation encapsulation of non-monitoring areas; (2) precise exposure of monitoring areas; (3) good adhesion and tensile matching between the encapsulation layer and the fiber; and (4) simple operation and small-batch manufacturing capability.

[0036] To address the aforementioned technical problems, this application provides a method for encapsulating fiber electrodes, comprising the following steps: First, a PET mask template with a preset pattern is prepared; the PET mask template has an open area, which can be used to restrict the local forming of nanoscale thin films; then, the PET mask template with the preset pattern is placed on the water surface where the SEBS film is formed, so that the open area of ​​the PET mask template is in full contact with the SEBS film, ensuring that the SEBS film is firmly attached to the patterned area of ​​the PET mask template, thus obtaining a mask template with a nanoscale SEBS film; next, two mask templates with nanoscale SEBS films are sandwiched and wrapped around conductive fibers from the top and bottom sides, respectively, utilizing the self-adhesiveness of the SEBS film to achieve stable adhesion between the film and the conductive fibers, thus constructing a sandwich encapsulation structure; subsequently, the SEBS film is gradually peeled off from the PET mask template, so that the film is firmly attached to the surface of the conductive fibers and gradually detaches from the mask template; finally, the encapsulated conductive fibers are completely removed from the two mask templates with nanoscale SEBS films, resulting in a stretchable conductive fiber structure with local insulating coating and functional exposure windows.

[0037] This application aims to provide a method for encapsulating conductive fiber electrodes to solve the problem of selective site encapsulation of fiber electrodes. It can also achieve effective insulation protection for the non-functional areas of conductive fibers, while retaining exposed conductive interfaces in the monitoring area to meet the functional requirements during electrophysiological signal acquisition and effectively prevent environmental corrosion of non-functional areas.

[0038] Specifically, the objectives of this application include:

[0039] 1. Achieve controllability of the encapsulation area. Ensure that conductivity is maintained only in the designated monitoring point area, while the rest has good electrical insulation properties.

[0040] 2. Ensure mechanical compatibility between conductive fibers and the encapsulation layer. This guarantees mechanical stability and adhesion between the encapsulation structure and the conductive fibers, improving reliability under dynamic operating conditions such as tension and bending, and preventing cracking, detachment, or stress concentration of the encapsulation layer.

[0041] 3. Simplifies the packaging process. Improves operational efficiency and process repeatability, making it suitable for high-volume applications.

[0042] The embodiments of this application will now be described in detail with reference to the accompanying drawings. However, those skilled in the art will understand that many technical details have been provided in the embodiments of this application to facilitate a better understanding of the application. However, the technical solutions claimed in this application can be implemented even without these technical details and various variations and modifications based on the following embodiments.

[0043] See Figure 1 This application provides a method for encapsulating a fiber electrode, comprising the following steps:

[0044] Step S1: Prepare a PET mask template with a preset pattern; the PET mask template has an opening area, which can be used to restrict the local forming of nanoscale thin films.

[0045] Step S2: Place the PET mask template with the preset pattern on the water surface where the SEBS film is formed, so that the opening area of ​​the PET mask template is in full contact with the SEBS film, ensuring that the SEBS film is firmly attached to the pattern area of ​​the PET mask template, and obtain a mask template with a nanoscale SEBS film.

[0046] Step S3: Two mask templates with nanoscale SEBS films are sandwiched and wrapped around the conductive fibers from the top and bottom sides respectively. The self-adhesive properties of the SEBS film are used to achieve stable adhesion between the film and the conductive fibers, thus constructing a sandwich encapsulation structure. Then, the SEBS film is gradually peeled off from the PET mask template, so that the film is firmly attached to the surface of the conductive fibers and gradually detaches from the mask template.

[0047] Step S4: The encapsulated conductive fiber is removed as a whole from two mask templates with nanoscale SEBS films to obtain a stretchable conductive fiber structure with local insulation coating and functional exposure windows.

[0048] This application provides a method for encapsulating flexible conductive fibers, achieving selective insulation encapsulation of non-exposed areas. The core of this method lies in using a customized mask template to prepare a nanoscale elastic insulating SEBS (styrene-ethylene-butene-styrene block copolymer, hereinafter referred to as SEBS) film, and achieving precise encapsulation of the fiber electrode through a double-layer film coating structure. The method includes the following key steps:

[0049] First, a mask template with a specific pattern (such as controllable window size, shape, and spacing) is prepared using a laser marking machine. This template is then used as a constrained structure to form an SEBS film with a nanometer-scale thickness. Under the influence of the mask, the SEBS film can have predefined opening areas, thus forming exposed windows only at pre-set monitoring points on the conductive fibers.

[0050] Subsequently, two patterned SEBS films are sandwiched between the conductive fibers from the top and bottom, respectively, utilizing the self-adhesive properties of the SEBS films to achieve stable adhesion between the films and fibers. Then, the SEBS films are gradually peeled off from the mask template, simultaneously completing the insulation of the non-functional areas of the fibers and forming stable, precisely sized conductive exposed areas at the monitoring points.

[0051] In some embodiments, step S1, preparing a PET mask template with a preset pattern, includes: positioning the exposed area on the conductive fiber according to the functional design of the conductive fiber to be encapsulated; drawing a pattern of the mask template according to the position, size, and shape of the exposed area on the conductive fiber, for subsequent determination of the patterned forming area of ​​the nanoscale SEBS film; importing the pattern of the mask template into an ultraviolet laser marking system, and performing high-precision pattern cutting on a high-transparency PET film using an ultraviolet laser marking machine to obtain a PET mask template with a preset pattern.

[0052] In some embodiments, the water surface in step S2 for forming the SEBS film includes: preparing a clean culture dish that matches the packaging size and filling it with deionized water to ensure that the water surface is flat, free of bubbles and impurities; adding a 5%-20% mass fraction SEBS toluene solution to the central area of ​​the culture dish containing clean water, and the solution rapidly spreads on the water surface to form a stable nanofilm.

[0053] In some embodiments, the SEBS film in step S2 is a styrene-ethylene-butene-styrene block copolymer film. Preferably, the mass fraction of the SEBS toluene solution is 7%.

[0054] In some embodiments, after adding SEBS toluene solution in step S2 and letting it stand for 10 seconds, a transparent and continuous nanofilm can be formed on the water surface, with a thickness of 50 nm to 200 nm.

[0055] In some embodiments, the process of obtaining a mask template with a nanoscale SEBS film in step S2 includes: after placing a PET mask template with a preset pattern on the water surface where the SEBS film is formed, using tweezers to remove the SEBS film from the excess area outside the PET mask template, ensuring that the SEBS film layer is retained only in the area where the desired opening is located, thereby obtaining a mask template with the pattern area covered by a nanoscale SEBS film, so as to achieve functional coating of the local area of ​​the conductive fiber.

[0056] In some embodiments, step S3 involves sandwiching conductive fibers with two mask templates bearing nanoscale SEBS films from the top and bottom, respectively. The self-adhesive properties of the SEBS film are used to achieve stable adhesion between the film and the conductive fibers, thus constructing a sandwich encapsulation structure. This includes: using two mask templates bearing nanoscale SEBS films as the upper and lower layers of the encapsulation, respectively; laying conductive fibers flat on the SEBS film surface of the lower mask template, ensuring that the target exposed area of ​​the conductive fibers is accurately aligned with the pattern opening on the mask template during positioning; and then aligning the upper mask template with the lower mask template from above and covering the conductive fibers, so that the conductive fibers are located between the two SEBS films, thus constructing a sandwich encapsulation structure.

[0057] In some embodiments, the encapsulation material in the sandwich encapsulation structure in step S3 is a nano-thickness thin film material with good biocompatibility and good insulation.

[0058] In some embodiments, step S3 involves gradually peeling the SEBS film off the PET mask template to firmly attach the film to the conductive fiber surface and gradually detach it from the mask template. This includes: after the film and conductive fiber are bonded together, using tweezers and scissors to gently peel the SEBS film off the PET mask template along the edge of the SEBS film on the mask template to firmly attach the film to the conductive fiber surface and gradually detach it from the PET mask template.

[0059] In some embodiments, in step S4, in a stretchable conductive fiber structure with partial insulation covering and functional exposure windows, the surface area of ​​the conductive fiber is covered with a highly flexible, highly elastic and biocompatible SEBS film, and the functional exposure windows are reserved only in a pre-defined opening area to achieve specific functions such as electrode contact, electrical signal acquisition or electrical stimulation output.

[0060] The encapsulation method of the fiber electrode provided in this application will be described in detail below through specific embodiments.

[0061] Step 1: Mask design.

[0062] The mask for fabricating the nanoscale SEBS thin film was prepared using a UV laser marking machine. First, based on the functional design of the conductive fibers to be encapsulated, the areas that need to remain exposed during use, i.e., the "exposed points," were identified. These exposed points are typically functional areas for electrical signal acquisition or electrical stimulation output; their specific location, size, and shape should be determined according to actual application requirements, such as the distribution of target tissue, spatial wiring needs, or the accuracy of multi-point recording.

[0063] Secondly, after the exposure points are located, the pattern of the mask template is further drawn using CAD (Computer-Aided Design) based on the position, size, and shape of the desired exposure area determined on the fiber. This pattern is used to subsequently determine the patterned area for the nanoscale SEBS film. The accuracy of the mask pattern directly affects the dimensional control of the final exposure area; therefore, it is essential to ensure that the design drawing has high resolution and good clarity of graphic boundaries. Figure 2 Four different shaped mask designs for packaging are shown.

[0064] Finally, the completed CAD drawings are imported into the UV laser marking system, and a high-precision pattern is cut onto the high-transparency PET (polyethylene terephthalate) film using a UV laser marking machine. During the cutting process, the laser power, number of laser cycles, and scanning speed should be adjusted appropriately to ensure a clear, through-hole mask pattern is formed without damaging the integrity of the PET substrate. The resulting PET mask template has a pre-defined opening area, which can be used to restrict the localized forming of subsequent nanoscale films.

[0065] Step 2: Nanofilm preparation.

[0066] This step utilizes the self-assembly film-forming properties of SEBS toluene solution on a water surface to form a uniform, continuous, and ultrathin flexible insulating layer, laying the foundation for subsequent patterned encapsulation. The specific steps are as follows:

[0067] First, prepare two clean culture dishes that match the size of the subsequent encapsulation, and fill them with deionized water, ensuring the water surface is flat and free of bubbles and impurities. The key to this step is to provide a uniform and stable liquid environment, which is conducive to the spontaneous spreading and film formation of SEBS at the interface.

[0068] Next, using a dropper, take an appropriate amount of a 7.5% (w / w) SEBS toluene solution and carefully add it to the center of the water surface. Upon contact with the water surface, due to the difference in surface tension and the rapid diffusion and evaporation of the solvent, the SEBS solution can quickly spread on the water surface and spontaneously form a highly uniform nanoscale SEBS film. Typically, after adding the SEBS solution and allowing it to stand for about 10 seconds, a transparent, continuous ultrathin film layer will form on the water surface, with a thickness usually between tens and hundreds of nanometers.

[0069] Next, gently place the PET mask template with the preset pattern obtained in the first step onto the water surface where the SEBS film will form, ensuring that the pattern opening area is in full contact with the SEBS film and that the film adheres firmly to the pattern area of ​​the template. To avoid air bubbles or film breakage between the template and the water surface, a slow and even placement method should be used, and tweezers can be used to assist the operation if necessary.

[0070] Finally, using tweezers or other tools, excess SEBS film is removed from the mask template, ensuring that the SEBS film layer remains only in the desired opening areas. This results in a mask template with a patterned area covered by a nanoscale SEBS film. This structure can be used for subsequent precise encapsulation operations to achieve functional coating of localized areas of conductive fibers.

[0071] Step 3: Encapsulation with stretchable conductive fibers.

[0072] This step employs a "sandwich" encapsulation structure, precisely wrapping designated areas of the conductive fibers with two patterned SEBS film templates to form a flexible, stretchable composite fiber structure with insulating protection and functional exposure windows. The specific operation process is as follows:

[0073] First, prepare two mask templates with nanoscale SEBS films obtained in step two, which will serve as the upper and lower layers of the encapsulation structure. Lay conductive fibers flat on the SEBS film surface of the lower template, ensuring that the target exposed area of ​​the conductive fibers is accurately aligned with the pattern openings on the template. Then, align and cover the other template with a SEBS film from above, placing the conductive fibers between the two SEBS films to construct a "sandwich" encapsulation structure. Figure 3 A schematic diagram of a "sandwich" encapsulation structure is shown. Conductive fibers are placed between two identical SEBS nanofilms, which encapsulate the fibers due to their adhesiveness.

[0074] Because SEBS film itself has a certain degree of adhesion, when the upper and lower layers of film are laminated, they can not only stably bond with conductive fibers, but also spontaneously bond together as a whole. This structure can achieve rapid and stable encapsulation at room temperature without the need for additional adhesives or hot-pressing processes, effectively preventing the conductive fibers from being stretched or damaged during the encapsulation process.

[0075] After the film is laminated, the SEBS film is gently peeled off the PET template along the edge of the template using tweezers, allowing the film to adhere firmly to the conductive fiber surface and gradually detach from the mask template. Since the SEBS film is only present in the patterned opening area of ​​the mask template, the remaining conductive fibers remain exposed after encapsulation, achieving selective encapsulation of functional areas.

[0076] Finally, the encapsulated conductive fiber is removed from the two templates as a whole, resulting in a stretchable conductive fiber structure with partial insulation coverage and functional exposure windows.

[0077] The fiber electrode encapsulation method provided in this application firstly involves the fabrication of a nanoscale SEBS thin film using a water-surface self-assembly method. This method employs an interfacial tension-driven water-surface self-assembly technique to prepare a large-area, uniform, and ultrathin SEBS nanofilm. Specifically, a 7.5% (w / w) SEBS toluene solution is dropped into the central region of a petri dish containing water, where the solution rapidly spreads on the water surface and forms a stable nanofilm. This process requires no special atmosphere or high-temperature conditions and offers advantages such as ease of operation, low cost, and high reproducibility.

[0078] Secondly, this application yields a patterned nanoscale SEBS film. The SEBS film used in the encapsulation process of this application is a patterned SEBS film. This method involves gently laying a PET mask template, laser-cut into a specific pattern, onto the surface of the SEBS film. This precisely removes non-target areas of the film, ensuring that the SEBS film remains only at the positions corresponding to the patterned holes, thus obtaining a patterned nanoscale SEBS film. This method effectively solves the problems of difficult patterning of nanofilms, complex operation, and poor uniformity in traditional methods, providing a foundation for subsequent precise encapsulation.

[0079] It should be noted that the SEBS solution used in this application is a toluene solution with a concentration of 5%-20%, among which a 7.5% toluene solution has the best effect.

[0080] Furthermore, this application employs a sandwich-type adhesive encapsulation process. Utilizing the natural adhesiveness and good flexibility of SEBS film, this application proposes a sandwich-type encapsulation method that eliminates the need for additional adhesives or hot-pressing processes. Two patterned SEBS films are bonded to conductive fibers from top to bottom, respectively, and gentle pressure is applied to ensure full contact between the films and fiber surfaces. During this process, the SEBS films simultaneously achieve self-adhesive bonding between the film and the fiber, as well as between the two films, thereby achieving a stable and complete encapsulation effect.

[0081] Subsequently, using tools such as tweezers and scissors, the SEBS film is peeled off the PET mask as a whole, transferring and fixing it onto the surface of the conductive fibers. This process does not require high temperatures or special equipment, effectively avoiding structural damage and electrical performance loss to the conductive fibers. Simultaneously, the adhesion area of ​​the SEBS film is defined by a pattern template, achieving precise encapsulation of localized areas of the fiber.

[0082] The encapsulation method for stretchable conductive fibers described in this application uses an ultra-thin film to encapsulate all electrode areas except for the exposed parts of the electrodes, in order to avoid leakage. The encapsulation layer material is a nano-thickness film material with good biocompatibility and good insulation.

[0083] The encapsulable electrode mentioned in the encapsulation method of this application is made of an electrode material that can have good adhesion to a nanoscale SEBS film. Since SEBS has very good stretchability, the electrode can be stretchable, or it can be a non-stretchable flexible soft electrode, or it can be a rigid electrode.

[0084] In step three, the final conductive fiber structure has a precisely controlled “exposed-encapsulated” area distribution. Most of the conductive fiber surface is covered by a highly flexible, highly elastic, and biocompatible SEBS film, with functional exposure windows reserved only at pre-set locations to achieve specific functions such as electrode contact, electrical signal acquisition, or electrical stimulation output.

[0085] The selective encapsulation method for flexible and stretchable conductive fibers proposed in this application has been systematically verified experimentally in multiple sets of samples. The results show that the method has good process stability and application effect. Using the process provided in this application, the non-functional regions of the conductive fiber can be accurately and stably encapsulated into an insulating state. The encapsulation layer and the fiber are firmly bonded, without bubbles or warping. The encapsulated area exhibits good tensile strength and bending adaptability, without significantly affecting the overall flexibility and mechanical properties. The monitoring point area remains exposed, and the conductivity is not affected in any way. The electrical signal transmission is stable, and the noise level is low, meeting the requirements for high-quality electrophysiological signal acquisition.

[0086] Furthermore, by optimizing the selection of encapsulation materials and controlling the encapsulation process, this application effectively achieves the goal of functional differentiation in different regions of the conductive fiber: that is, only the preset monitoring area remains conductive, while the remaining areas are insulated, avoiding problems such as electrical short circuits and signal crosstalk. This not only solves the problems of poor flexibility, material detachment, uneven encapsulation, and difficulty in accurately controlling monitoring points in traditional encapsulation processes, but also achieves a high degree of matching between the encapsulation structure and the conductive fiber in terms of mechanical properties. The encapsulation structure remains intact under complex deformation conditions such as repeated stretching, bending, and compression, without cracking, peeling, or encapsulation failure.

[0087] Compared with existing technologies, the fiber electrode encapsulation method provided in this application has the following advantages:

[0088] 1. Precise patterning capabilities.

[0089] This application utilizes CAD design and laser-cut masks to precisely control the SEBS film adhesion area and achieve predetermined exposure windows, making it suitable for applications such as functional electrodes and exposed contacts.

[0090] 2. Low-temperature non-destructive process.

[0091] This application requires no high temperature, no solvent evaporation or photocuring during the entire encapsulation process, which greatly protects the conductivity and structural integrity of the conductive fibers, and is particularly suitable for temperature-sensitive materials (such as liquid metal composite fibers).

[0092] 3. Nanoscale ultrathin encapsulation layer.

[0093] The thickness of the SEBS film in this application can be controlled at the nanometer level (tens to hundreds of nanometers). After encapsulation, it hardly increases the thickness or stiffness of the fiber, maintaining its good tensile strength and skin-fit properties.

[0094] 4. Easy to operate and can be implemented in batches.

[0095] The process of this application is simple, requires no expensive equipment, can be completed under standard laboratory conditions, and has the potential to be extended to batch processing of multiple fibers.

[0096] 5. It has strong biocompatibility and wearability.

[0097] The SEBS material of this application has good biocompatibility, stretchability and skin affinity, making it suitable for long-term wear and use, and particularly suitable for human signal acquisition or nerve stimulation applications.

[0098] Based on the above technical solutions, this application provides a method for encapsulating a fiber electrode. The method includes the following steps: First, a PET mask template with a preset pattern is prepared. The PET mask template has an open area, which can be used to restrict the local forming of a nanoscale thin film. Then, the PET mask template with the preset pattern is placed on the water surface where the SEBS film is formed, ensuring that the open area of ​​the PET mask template is in full contact with the SEBS film, thus ensuring that the SEBS film is firmly attached to the patterned area of ​​the PET mask template, thereby obtaining a mask template with a nanoscale SEBS film. Next, two mask templates with nanoscale SEBS films are sandwiched and wrapped around conductive fibers from the top and bottom sides, respectively. The self-adhesiveness of the SEBS film is used to achieve stable adhesion between the film and the conductive fibers, constructing a sandwich encapsulation structure. Subsequently, the SEBS film is gradually peeled off from the PET mask template, allowing the film to firmly adhere to the surface of the conductive fibers and gradually detach from the mask template. Finally, the encapsulated conductive fibers are completely removed from the two mask templates with nanoscale SEBS films, resulting in a stretchable conductive fiber structure with localized insulating coating and functional exposure windows.

[0099] This application provides a method for encapsulating fiber electrodes. This method utilizes a customized mask template to prepare a nanoscale elastic insulating SEBS (styrene-ethylene-butene-styrene block copolymer) film, and achieves selective insulating encapsulation of non-exposed areas through a double-layer film covering structure. The encapsulation method proposed in this application achieves precise definition and effective protection of the functional regions of flexible conductive fibers, reaching the technical goals of structural flexibility, conductive stability, simple process, and strong adaptability. It has good application prospects and promotional value, and is particularly suitable for wearable, implantable, and other electrophysiological systems with high requirements for structural flexibility and insulation reliability.

[0100] Those skilled in the art will understand that the above-described embodiments are specific examples of implementing this application, and in practical applications, various changes in form and detail may be made without departing from the spirit and scope of this application. Any person skilled in the art can make their own modifications and alterations without departing from the spirit and scope of this application; therefore, the scope of protection of this application should be determined by the scope defined in the claims.

Claims

1. A method for encapsulating a fiber electrode, characterized in that, Includes the following steps: Prepare a PET mask template with a preset pattern; the PET mask template has an opening area, which can be used to restrict the local forming of nanoscale thin films; A PET mask template with a preset pattern is placed on the water surface where the SEBS film is formed, so that the opening area of ​​the PET mask template is in full contact with the SEBS film, ensuring that the SEBS film is firmly attached to the pattern area of ​​the PET mask template, thus obtaining a mask template with a nanoscale SEBS film. Two mask templates with nanoscale SEBS films are sandwiched around conductive fibers from the top and bottom. The self-adhesive properties of the SEBS film are used to achieve a stable bond between the film and the conductive fibers, thus constructing a sandwich encapsulation structure. Subsequently, the SEBS film is gradually peeled off from the PET mask template, so that the film is firmly attached to the surface of the conductive fibers and gradually detaches from the mask template. The encapsulated conductive fiber was removed as a whole from two mask templates with nanoscale SEBS films to obtain a stretchable conductive fiber structure with local insulation coating and functional exposure windows.

2. The method for encapsulating a fiber electrode according to claim 1, characterized in that, Preparing a PET mask template with a preset pattern includes: Based on the functional design of the conductive fiber to be encapsulated, the exposed areas on the conductive fiber are located. Based on the location, size, and shape of the exposed area on the conductive fiber, a mask template pattern is drawn to determine the patterning area of ​​the nanoscale SEBS film. The pattern of the mask template is imported into the ultraviolet laser marking system, and the pattern is cut with high precision on the high-transparency PET film by the ultraviolet laser marking machine to obtain a PET mask template with the preset pattern.

3. The method for encapsulating a fiber electrode according to claim 1, characterized in that, The water surface on which the SEBS film forms includes: Prepare clean petri dishes that match the packaging size, and fill them with deionized water, ensuring that the water surface is flat, free of bubbles and impurities; When a 5%-20% mass fraction SEBS toluene solution is added dropwise to the center of a petri dish containing water, the solution spreads rapidly on the water surface and forms a stable nanoscale SEBS film.

4. The method for encapsulating a fiber electrode according to claim 1, characterized in that, SEBS film is a styrene-ethylene-butene-styrene block copolymer film.

5. The method for encapsulating a fiber electrode according to claim 3, characterized in that, After adding SEBS toluene solution and letting it stand for 10 seconds, a transparent, continuous nanofilm can be formed on the water surface, with a thickness of 50nm~200nm.

6. The method for encapsulating a fiber electrode according to claim 1, characterized in that, A mask template with a nanoscale SEBS thin film was prepared, comprising: After placing a PET mask template with a preset pattern on the water surface to form a SEBS film, tweezers are used to remove the SEBS film from the excess area outside the PET mask template, ensuring that the SEBS film layer is retained only in the area where the desired opening is located. This results in a mask template with the patterned area covered by a nanoscale SEBS film, thus achieving functional coating of local areas of conductive fibers.

7. The method for encapsulating a fiber electrode according to claim 1, characterized in that, Two mask templates with nanoscale SEBS films are sandwiched around conductive fibers from the top and bottom, respectively. The self-adhesive properties of the SEBS film are used to achieve a stable bond between the film and the conductive fibers, thus constructing a sandwich encapsulation structure, including: Two mask templates with nanoscale SEBS thin films are used as the upper and lower layers of the encapsulation, respectively. Conductive fibers are laid flat on the surface of the SEBS film, which serves as the lower mask template. During positioning, it is ensured that the target exposure area of ​​the conductive fibers is accurately aligned with the pattern opening on the mask template. Subsequently, the upper mask template is aligned from above with the lower mask template and covered with conductive fibers, so that the conductive fibers are located between the two SEBS films to construct a sandwich encapsulation structure.

8. The method for encapsulating a fiber electrode according to claim 1, characterized in that, The SEBS film is gradually peeled off from the PET mask template, allowing the film to adhere firmly to the conductive fiber surface, and then gradually detached from the mask template, including: After the film and conductive fibers are bonded together, use tweezers and scissors to gently peel the SEBS film off the PET mask template along the edge of the SEBS film, so that the film is firmly attached to the surface of the conductive fibers and gradually detached from the PET mask template.

9. The method for encapsulating a fiber electrode according to claim 1, characterized in that, The encapsulation material in the sandwich-type packaging structure is a nano-thickness thin film material with good biocompatibility and good insulation.

10. The method for encapsulating a fiber electrode according to claim 1, characterized in that, In a stretchable conductive fiber structure with partial insulation covering and functional exposure windows, the surface area of ​​the conductive fiber is covered by a highly flexible, highly elastic and biocompatible SEBS film, and functional exposure windows are reserved only in pre-defined opening areas to realize the functions of electrode contact, electrical signal acquisition or electrical stimulation output.

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