Packaging method of fiber electrode

Abstract

The invention relates to the technical field of biological interface sensing, in particular to a fiber electrode packaging method which comprises the following steps: preparing a PET mask template with a preset pattern; placing the PET mask template with the preset pattern on the water surface on which the SEBS thin film is formed to prepare a mask template with a nanoscale SEBS thin film; carrying out interlayer type coating on the conductive fibers from the upper side and the lower side by using two mask templates with nanoscale SEBS films respectively to construct an interlayer type packaging structure; gradually stripping the SEBS film from the PET mask template; and integrally taking out the packaged conductive fiber from the two mask templates with the nanoscale SEBS films to obtain the stretchable conductive fiber structure with the local insulation coating and the functional exposure window. According to the application, effective insulation protection of the non-functional area of the conductive fiber can be realized, and meanwhile, an exposed conductive interface is reserved in the monitoring area, so that the functional requirement during electrophysiological signal acquisition is met, and corrosion of the environment to the non-functional area is effectively prevented.

Description

Technical Field

[0001] The present application relates to the field of biointerface sensing technology, and in particular to a packaging method for fiber electrodes. Background Art

[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, offer significant advantages in next-generation electrophysiological systems. These conductive fibers can not only be woven into or adhered to the skin surface for biosignal collection, but can also be used in certain implantable physiological interface scenarios, demonstrating promising application prospects.

[0003] Flexible conductive fibers usually have a linear overall conductive structure, and the entire fiber has the ability to conduct current. However, while this characteristic gives conductive fibers good signal conduction capabilities, it also brings some problems. For example, when used to construct multi-channel electrode arrays or to lay out complex signal acquisition paths, it is not necessary for the entire fiber to remain conductively exposed. Instead, only the conductive area is retained near the set electrode "monitoring point", and the rest needs to be effectively insulated and packaged to ensure isolation between channels, accurate positioning of electrophysiological signals, and long-term stability of the overall system.

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

[0005] An embodiment of the present application provides a packaging method for a fiber electrode, which can achieve effective insulation protection for the non-functional area of ​​the conductive fiber, while retaining an 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 area.

[0006] To solve the above technical problems, an embodiment of the present application provides a fiber electrode packaging method, comprising the following steps: first, preparing a PET mask template with a preset pattern; the PET mask template has an opening area that can be used to limit the local formation of a nano-scale film; then, placing the PET mask template with a 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 preparing a mask template with a nano-scale SEBS film; then, sandwich-coating the conductive fiber with two mask templates with nano-scale SEBS films from the upper and lower sides respectively, utilizing the self-adhesiveness of the SEBS film to achieve stable bonding between the film and the conductive fiber, and constructing a sandwich packaging structure; then, gradually peeling the SEBS film 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 removed as a whole from the two mask templates with nano-scale SEBS films, and a stretchable conductive fiber structure with local insulating coating and functional exposure window is obtained.

[0007] In some exemplary embodiments, a PET mask template with a preset pattern is prepared, including: positioning the exposed area on the conductive fiber according to the functional design of the conductive fiber to be encapsulated; drawing the 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 molding area of ​​the nano-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 by the ultraviolet laser marking machine to obtain a PET mask template with a preset pattern.

[0008] In some exemplary embodiments, forming a water surface of the SEBS film includes: preparing clean culture dishes matching the package size and filling them with deionized water to ensure that the water surface is flat and free of bubbles and impurities; adding a 5%-20% by mass fraction of SEBS toluene solution dropwise to the center area of ​​the culture dish containing clean water, and the solution quickly spreads on the water surface to form a stable nanofilm.

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

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

[0011] In some exemplary embodiments, a mask template with a nano-scale SEBS film is prepared, including: 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 on the excess area outside the PET mask template, ensuring that the SEBS film layer is retained only in the required opening area, thereby obtaining a mask template in which the pattern area is covered with a nano-scale SEBS film to achieve functional coating of the local area of ​​the conductive fiber.

[0012] In some exemplary embodiments, two mask templates with nano-scale SEBS films are used to sandwich-coat the conductive fibers from the upper and lower sides, respectively, and the self-adhesiveness of the SEBS films is used to achieve stable adhesion between the films and the conductive fibers, thereby constructing a sandwich packaging structure, including: using the two mask templates with nano-scale SEBS films as the upper and lower layers of the package, respectively; laying the conductive fibers flat on the surface of the SEBS film of the mask template serving as the lower layer, and positioning the conductive fibers so as to ensure that the target exposure area of ​​the conductive fibers is accurately aligned with the pattern opening on the mask template; subsequently, aligning the mask template serving as the upper layer with the mask template of the lower layer from above and covering the conductive fibers, so that the conductive fibers are located between the two layers of SEBS films, thereby constructing a sandwich packaging structure.

[0013] In some exemplary embodiments, 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 detached from the mask template, including: after the film and the conductive fiber are completely bonded, using tweezers and scissors to gently peel the SEBS film from the PET mask template along the edge of the mask template of the SEBS film so that the film is firmly attached to the surface of the conductive fiber and gradually detached from the PET mask template.

[0014] In some exemplary embodiments, the packaging material in the sandwich packaging structure is a nanometer-thick thin film material with good biocompatibility and good insulation properties.

[0015] In some exemplary embodiments, in a stretchable conductive fiber structure having a local insulating coating and a functional exposure window, the surface area of ​​the conductive fiber is coated with a highly flexible, highly elastic and biocompatible SEBS film, and only the functional exposure window is retained in the pre-set opening area to achieve the functions of electrode contact, electrical signal acquisition or electrical stimulation output.

[0016] The technical solution provided by the embodiments of the present application has at least the following advantages: An embodiment of the present application provides a method for packaging a fiber electrode, the method comprising the following steps: first, preparing a PET mask template with a preset pattern; the PET mask template has an opening area that can be used to limit the local formation of a nano-scale film; then, placing the PET mask template with the preset pattern on a water surface where a 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 preparing a mask template with a nano-scale SEBS film; then, sandwich-coating the conductive fiber with two mask templates with nano-scale SEBS films from the upper and lower sides respectively, utilizing the self-adhesiveness of the SEBS film to achieve stable bonding between the film and the conductive fiber, thereby constructing a sandwich packaging structure; then, gradually peeling the SEBS film 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, removing the encapsulated conductive fiber as a whole from the two mask templates with nano-scale SEBS films, thereby obtaining a stretchable conductive fiber structure with local insulating coating and functional exposure windows.

[0017] This application provides a fiber electrode packaging method that utilizes a customized mask template to prepare a nanoscale elastic insulating SEBS (styrene-ethylene-butylene-styrene block copolymer) film. This method achieves selective insulation packaging of non-exposed areas through a double-layer membrane wrapping structure. This packaging method, proposed in this application, precisely defines and effectively protects the functional regions of flexible conductive fibers, achieving the technical goals of structural flexibility, stable conductivity, simple processing, and strong adaptability. The method has promising application prospects and promotional value, and is particularly suitable for wearable and implantable electrophysiological systems that require high structural flexibility and insulation reliability. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] One or more embodiments are exemplarily described by the pictures in the corresponding drawings. These exemplifications do not constitute limitations on the embodiments. Unless otherwise stated, the pictures in the drawings do not constitute proportional limitations.

[0019] Figure 1 A schematic flow chart of a fiber electrode packaging method provided in one embodiment of the present application.

[0020] Figure 2 Schematic diagram of the structures of four masks for packaging designed in different shapes provided in one embodiment of the present application.

[0021] Figure 3 A schematic diagram of a sandwich packaging structure provided in one embodiment of the present application. DETAILED DESCRIPTION

[0022] As can be seen from the background technology, there is currently a lack of an efficient and selective packaging method for the overall conductive fiber electrode that can simultaneously meet the technical requirements of precise exposure of the monitoring area and selective insulation packaging of the non-monitoring area.

[0023] In the field of electrophysiological signal monitoring, such as electroencephalography (EEG), electrocardiography (ECG), electromyography (EMG), and neural signal recording, the performance of electrodes plays a decisive role in signal quality. In recent years, the rapid development of flexible wearable electronic technology has promoted the research of electrode systems based on fiber structures. Fiber electrodes are small in size and have good flexibility and stretchability, and are one of the future development directions of electrodes. However, in actual use, the electrode system constructed by conductive fibers does not require continuous conductivity as a whole. On the contrary, in order to ensure the spatial resolution of the signal and the independence of the channels, it is necessary to maintain conductivity only in specific areas (such as the "monitoring point" in contact with the tissue), while the rest must be effectively insulated and encapsulated to prevent signal crosstalk, environmental interference, and reliability and durability issues.

[0024] Specifically, signal crosstalk refers to the situation where multiple fiber electrodes, if all conductive, are placed close to or cross-connected, which can easily generate crosstalk or artifact signals, affecting the accuracy and repeatability of electrophysiological data. Environmental interference refers to the situation where uninsulated areas are susceptible to external electric fields, electromagnetic waves, or humidity changes, leading to baseline drift and increased noise. Reliability and durability issues refer to the situation where exposed conductive areas are susceptible to friction, oxidation, or mechanical damage, reducing electrode life.

[0025] Currently, in the field of flexible conductive fiber packaging and patterning, there are a variety of mature technical solutions that have been applied to wearable electronic devices, implantable electrodes, and flexible sensing systems. These mainly include the following methods: 1. Overall coating and impregnation packaging technology.

[0026] The technical principle of this method is to immerse the conductive fiber as a whole in a liquid elastomer such as PDMS, PU, ​​silicone, or form a coating layer on its surface by scraping or dripping, and then cure it at room temperature or heat. This method usually immerses the conductive fiber directly in a liquid elastomer (such as PDMS, PU, ​​Ecoflex, etc.), or forms a complete coating layer on its surface by scraping, spin coating, spraying, etc. After curing, it can provide good flexibility and insulation performance, which is suitable for large-area continuous packaging needs. The disadvantages of this method are: (1) lack of pattern selectivity, unable to control the specific exposure area, and all conductive parts are covered; (2) the coating thickness is large, which significantly increases the fiber diameter and reduces the softness and tensile properties; (3) the coating quality is easily affected by bubbles and fluidity, and the process stability is poor; (4) the curing time is long, which is difficult to meet the needs of large-scale rapid preparation.

[0027] 2. Thermal bonding film packaging technology (such as TPU film hot pressing method).

[0028] The technical principle of this method is: the conductive fiber is sandwiched between two thermoplastic films (such as TPU), and the films are melted and bonded under heating conditions by a hot pressing device to form a packaging structure. This method usually uses thermoplastic elastomer films (such as TPU, PET / EVA, etc.) to perform sandwich hot pressing packaging on the conductive fiber. This type of method uses the adhesiveness of the film under heating conditions to achieve the fusion and bonding of the upper and lower packaging films, which is suitable for the packaging structure design of high-strength flexible electronic devices. Technical principle: However, this method also has some disadvantages: (1) The packaging 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 laboratory preparation; (3) The film thickness is generally more than tens of microns, which is not conducive to high-flexibility scenarios such as skin adhesion; (4) The hot pressing area is difficult to accurately align and control, which can easily cause window position errors.

[0029] 3. Photocuring patterned encapsulation technology (such as PEGDA or SU-8 method).

[0030] The technical principle of this method is to coat the surface of the conductive fiber with a photosensitive polymer, and then achieve local exposure and patterned curing through mask illumination to form a structured encapsulation layer. This method is usually based on regional exposure and development of photosensitive polymers (such as PEGDA, SU-8, etc.) to achieve patterned coating on the conductive fiber. It is often combined with a mask and UV exposure system and can be used to construct functional windows or insulating patterns with micron-scale precision. The disadvantages of this method are: (1) Photoinitiator and biotoxicity issues limit its promotion in skin bonding or biological applications; (2) The mechanical properties of the cured film layer are poor and it is easy to crack or fall off after long-term bending; (3) The requirements for UV light source, alignment system, and mask design are high, and the process window is narrow, which is not conducive to promotion; (4) The thickness of the coating step is difficult to control, and it is difficult to achieve nano-level ultra-thin structures.

[0031] 4. Microfluidic encapsulation (such as controlled injection of colloid coating) The technical principle of this method is to use microfluidics or controlled dripping to quantitatively inject liquid coating materials into a preset channel or mold to form a localized coating effect. This technology uses precision control equipment such as microfluidic chips and syringe pumps to guide the liquid packaging material to the preset coating area. It is suitable for flexible electronic or microsystem packaging scenarios that require precise control of the packaging position and shape. 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 packaging; (3) the mold design is complex and the flexibility of structural changes is poor.

[0032] Therefore, there is currently a lack of an efficient and selective packaging method for integral conductive fiber electrodes that can simultaneously meet the following technical requirements: (1) selective insulation packaging of non-monitoring areas; (2) precise exposure of monitoring areas; (3) good adhesion and tensile matching between the packaging layer and the fiber; and (4) simple operation and small-batch manufacturing.

[0033] In order to solve the above technical problems, the present application provides a fiber electrode packaging method, comprising the following steps: first, preparing a PET mask template with a preset pattern; the PET mask template has an opening area that can be used to limit the local formation of a nanoscale film; then, placing the PET mask template with a 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 preparing a mask template with a nanoscale SEBS film; then, sandwich-coating the conductive fiber with two mask templates with nanoscale SEBS films from the upper and lower sides respectively, utilizing the self-adhesiveness of the SEBS film to achieve stable bonding between the film and the conductive fiber, and constructing a sandwich packaging structure; then, gradually peeling off the SEBS film 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 removed as a whole from the two mask templates with nanoscale SEBS films to obtain a stretchable conductive fiber structure with local insulating coating and functional exposure window.

[0034] The present application aims to provide a packaging method for conductive fiber electrodes to solve the problem of selective point packaging of fiber electrodes, and to achieve effective insulation protection for non-functional areas of the conductive fibers, while retaining exposed conductive interfaces in the monitoring area to meet its functional requirements during electrophysiological signal acquisition and effectively prevent environmental corrosion of non-functional areas.

[0035] Specifically, the objectives of this application include: 1. Achieve controllability of the packaging area. Ensure that only the designated monitoring point area is conductive and the rest of the area has good electrical insulation performance.

[0036] 2. Ensure mechanical matching between the conductive fiber and the encapsulation layer. Ensure mechanical stability and adhesion between the encapsulation structure and the conductive fiber, improve reliability under dynamic working conditions such as stretching and bending, and avoid cracking, shedding, or stress concentration in the encapsulation layer.

[0037] 3. Simplify the packaging process. Improve operational efficiency and process repeatability, suitable for high-volume applications.

[0038] The following detailed description of the various embodiments of the present application is provided in conjunction with the accompanying drawings. However, those skilled in the art will appreciate that many technical details are provided in the various embodiments of the present application to facilitate a better understanding of the present application. However, even without these technical details and the various variations and modifications based on the following embodiments, the technical solutions claimed in the present application can still be implemented.

[0039] See Figure 1 , an embodiment of the present application provides a packaging method for a fiber electrode, comprising the following steps: Step S1: preparing a PET mask template with a preset pattern; the PET mask template has an opening area that can be used to limit the local formation of the nano-scale film.

[0040] Step S2: Place the PET mask template with a 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 nano-scale SEBS film.

[0041] Step S3: Two mask templates with nano-scale SEBS films are used to sandwich the conductive fibers from the upper and lower sides, respectively. The self-adhesiveness of the SEBS films is used to achieve stable adhesion between the films and the conductive fibers, thereby constructing a sandwich packaging structure. Subsequently, the SEBS films are gradually peeled off from the PET mask templates, so that the films are firmly attached to the surface of the conductive fibers and gradually detached from the mask templates.

[0042] Step S4: The encapsulated conductive fiber is taken out as a whole from the two mask templates with the nano-SEBS film to obtain a stretchable conductive fiber structure with a local insulating coating and a functional exposure window.

[0043] This application provides a method for encapsulating flexible conductive fibers, achieving selective insulation encapsulation of non-exposed areas. The core of this method is to use a customized mask template to prepare a nanoscale elastic insulating SEBS (styrene-ethylene-butylene-styrene block copolymer, hereinafter referred to as SEBS) film, and then achieve precise encapsulation of the fiber electrodes through a double-layer membrane coating structure. The method includes the following key steps: First, a laser marking machine creates a mask template with a specific pattern (e.g., controllable window size, shape, and spacing). This serves as a defining structure for forming a nanometer-thick SEBS film. The mask creates predefined openings in the SEBS film, creating exposed windows only at the designated monitoring points on the conductive fibers.

[0044] Two patterned SEBS films are then applied to the conductive fibers in a "sandwich" fashion, one above the other. The SEBS film's self-adhesive properties ensure a stable bond between the two fibers. The SEBS films are then gradually peeled from the mask, naturally insulating the non-functional areas of the fibers and creating a stable, precisely dimensioned conductive bare area at the monitoring point.

[0045] In some embodiments, a PET mask template with a preset pattern is prepared in step S1, including: positioning the exposed area on the conductive fiber according to the functional design of the conductive fiber to be encapsulated; drawing the 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 molding area of ​​the nano-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 by the ultraviolet laser marking machine to obtain a PET mask template with a preset pattern.

[0046] In some embodiments, forming the water surface of the SEBS film in step S2 includes: preparing clean culture dishes matching the package size and filling them with deionized water to ensure that the water surface is flat and free of bubbles and impurities; adding a 5%-20% mass fraction of SEBS toluene solution dropwise to the center area of ​​the culture dish filled with clean water, and the solution quickly spreads on the water surface to form a stable nanofilm.

[0047] In some embodiments, the SEBS film in step S2 is a styrene-ethylene-butylene-styrene block copolymer film. Preferably, the mass fraction of the SEBS toluene solution is 7%.

[0048] In some embodiments, after the SEBS toluene solution is added dropwise in step S2 and then left to stand for 10 seconds, a transparent, continuous nanofilm can be formed on the water surface. The thickness of the nanofilm is 50 nm to 200 nm.

[0049] In some embodiments, a mask template with a nano-scale SEBS film is prepared in step S2, including: 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 on the excess area outside the PET mask template, ensuring that the SEBS film layer is retained only in the required opening area, thereby obtaining a mask template in which the pattern area is covered with a nano-scale SEBS film to achieve functional coating of the local area of ​​the conductive fiber.

[0050] In some embodiments, in step S3, two mask templates with nano-scale SEBS films are used to sandwich the conductive fibers from the upper and lower sides, respectively, and the self-adhesiveness of the SEBS films is used to achieve stable adhesion between the films and the conductive fibers, thereby constructing a sandwich packaging structure, including: using the two mask templates with nano-scale SEBS films as the upper and lower layers of the package, respectively; laying the conductive fibers flat on the surface of the SEBS film of the mask template serving as the lower layer, and ensuring that the target exposure area of ​​the conductive fibers is accurately aligned with the pattern opening on the mask template during positioning; then, aligning the mask template serving as the upper layer with the mask template of the lower layer from above and covering the conductive fibers, so that the conductive fibers are located between the two layers of SEBS films, thereby constructing a sandwich packaging structure.

[0051] In some embodiments, the packaging material in the sandwich packaging structure in step S3 is a nanometer-thick thin film material with good biocompatibility and good insulation properties.

[0052] In some embodiments, in step S3, 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 detached from the mask template, including: after the film and the conductive fiber are completely bonded, using tweezers and scissors to gently peel the SEBS film from the PET mask template along the edge of the mask template of the SEBS film so that the film is firmly attached to the surface of the conductive fiber and gradually detached from the PET mask template.

[0053] In some embodiments, in step S4, in a stretchable conductive fiber structure having a local insulating coating and a functional exposure window, the surface area of ​​the conductive fiber is coated with a highly flexible, highly elastic and biocompatible SEBS film, and only the functional exposure window is retained in the pre-set opening area to achieve specific functions such as electrode contact, electrical signal acquisition or electrical stimulation output.

[0054] The packaging method of the fiber electrode provided in the present application is described in detail below through specific examples.

[0055] Step 1: Mask design.

[0056] The mask for preparing the nanoscale SEBS film is produced 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, known as "exposure points," are identified. These exposure points are typically functional areas for electrical signal acquisition or electrical stimulation output. Their specific location, size, and shape should be determined based on actual application requirements, such as target tissue distribution, spatial wiring requirements, and multi-point recording accuracy.

[0057] After the exposure points are located, a CAD (Computer-Aided Design) tool is used to create a mask template based on the location, size, and shape of the desired exposure area on the fiber. This tool is then used to define the patterned areas for the nano-SEBS film. The accuracy of the mask pattern directly affects the size of the final exposure area, so the design must have high resolution and good image boundary definition. Figure 2 Four different shapes of mask designs for packaging are shown.

[0058] Finally, the completed CAD drawings are imported into a UV laser marking system, where they are used to perform high-precision pattern cutting on a highly transparent PET (polyethylene terephthalate) film. Laser power, laser cycles, and scanning speed are carefully adjusted during the cutting process to ensure a clear, continuous mask pattern without damaging the integrity of the PET substrate. The resulting PET mask template features pre-defined openings, which can be used to localize the subsequent nanoscale film formation. Step 2: Preparation of nanofilm.

[0059] This step utilizes the self-assembly film-forming properties of SEBS toluene solution on the water surface to form a uniform, continuous, ultra-thin flexible insulating layer, laying the foundation for subsequent patterned packaging. The specific steps are as follows: First, prepare two clean Petri dishes that match the size of the subsequent packaging and fill them with deionized water, ensuring the water surface is flat, free of bubbles and impurities. The key to this step is to provide a uniform and stable liquid surface environment, which is conducive to the spontaneous spreading and film formation of SEBS on the interface.

[0060] Next, use a rubber-tipped dropper to carefully drip a 7.5% SEBS toluene solution onto the center of the water surface. Upon contact with the water, the SEBS solution rapidly spreads and spontaneously forms a highly uniform nanoscale SEBS film due to surface tension differences and the rapid diffusion and volatilization of the solvent. Typically, after about 10 seconds of allowing the SEBS solution to sit, a transparent, continuous, ultra-thin film, typically tens to hundreds of nanometers thick, forms on the surface.

[0061] Next, gently place the PET mask template with the preset pattern, prepared in the first step, onto the water surface where the SEBS film has been formed, ensuring that the patterned openings are in full contact with the SEBS film and that the film is firmly attached to the patterned area of ​​the template. To avoid bubbles forming between the template and the water surface or causing the film to rupture, place the mask slowly and evenly, using tweezers if necessary.

[0062] Finally, use tweezers or other tools to remove the excess SEBS film from the mask template, ensuring that the SEBS film layer remains only in the desired opening areas. This results in a mask template with the patterned area covered with a nanoscale SEBS film. This structure can be used for the next step of precise packaging operations to achieve functional coating of localized areas of the conductive fibers.

[0063] Step 3: Stretchable conductive fiber packaging.

[0064] This step uses a "sandwich" packaging structure, using two patterned SEBS film templates to precisely coat the designated areas of the conductive fiber, forming a flexible, stretchable composite fiber structure with insulation protection and functional exposure windows. The specific operation process is as follows: First, two mask templates with nano-SEBS films, obtained in step 2, are prepared to serve as the upper and lower layers of the package. Conductive fibers are laid flat on the SEBS film surface of the lower template, ensuring that the target exposed areas of the conductive fibers align precisely with the patterned openings on the template. Next, another template with SEBS films is aligned and placed over the top, positioning the conductive fibers between the two layers of SEBS film to create a "sandwich" package structure. Figure 3 A schematic diagram of a "sandwich" packaging structure is shown. The conductive fiber is placed between two identical SEBS nanofilms, which wrap the fiber due to their adhesive properties.

[0065] Because SEBS film has a certain degree of adhesion, when the upper and lower layers are laminated, they not only stably bond to the conductive fibers but also spontaneously bond to each other, forming a single unit. This structure achieves fast and stable encapsulation at room temperature without the need for additional adhesives or heat pressing, effectively preventing the conductive fibers from being stretched or damaged during the encapsulation process.

[0066] After the film is attached, tweezers are used to gently peel the SEBS film from the PET template along the edge of the template, firmly adhering the film to the surface of the conductive fiber and gradually separating it from the mask template. Because the SEBS film is only present in the pattern opening area of ​​the mask template, the rest of the conductive fiber remains exposed after encapsulation, achieving selective encapsulation of functional areas.

[0067] Finally, the encapsulated conductive fiber is taken out from the two templates as a whole to obtain a stretchable conductive fiber structure with local insulating coating and functional exposure window.

[0068] The present application provides a method for encapsulating fiber electrodes. First, the present application uses a surface self-assembly method to prepare a nanoscale SEBS film. This application uses a surface self-assembly method driven by interfacial tension to prepare a large-area, uniform, and ultra-thin SEBS nanofilm. Specifically, a 7.5% mass fraction of SEBS toluene solution is added dropwise to the center of a culture dish containing clean water. The solution quickly spreads on the water surface and forms a stable nanofilm. This process does not require special atmosphere or high temperature conditions and has the advantages of simple operation, low cost, and high repeatability.

[0069] Secondly, this application produces a patterned nanoscale SEBS film. The SEBS film used in the packaging process of this application is a patterned SEBS film. This method involves gently applying a PET mask template, laser-cut into a specific pattern, to the surface of the SEBS film. This precisely removes non-target areas of the film, leaving the SEBS film only in the locations corresponding to the patterned holes, thereby obtaining a patterned nano-SEBS film. This method effectively addresses the difficulties of nanofilm patterning, complex operations, and poor uniformity in traditional methods, providing a foundation for subsequent precision packaging.

[0070] It should be noted that the concentration of the SEBS solution used in this application is 5%-20% toluene solution, among which the toluene solution with a concentration of 7.5% has the best effect.

[0071] Furthermore, this application uses a sandwich-type adhesive packaging process. Taking advantage of the natural viscosity and good flexibility of the SEBS film, this application proposes a sandwich packaging method that does not require additional adhesives or hot pressing processes. Two patterned SEBS films are attached to the conductive fibers from the top and bottom, and light pressure is applied to ensure full contact between the film and the fiber surface. During this process, the SEBS film can simultaneously achieve self-adhesive bonding between the film and the fiber, as well as between the two films, thereby achieving a stable and complete coating effect.

[0072] The SEBS film is then peeled from the PET mask using tools such as tweezers and scissors, allowing it to be transferred and fixed to the surface of the conductive fiber. This process does not require high temperatures or specialized equipment, effectively avoiding structural damage to the conductive fiber and impairing its electrical properties. Furthermore, the patterned template defines the adhesion area of ​​the SEBS film, enabling precise encapsulation of localized areas of the fiber.

[0073] The present application describes a method for encapsulating stretchable conductive fibers. In this method, except for the exposed electrode portions, other electrode areas are encapsulated with ultra-thin films to avoid leakage. The encapsulation layer material selected is a nano-thick film material with good biocompatibility and good insulation properties.

[0074] The encapsulated electrode mentioned in the encapsulation method of the present application has an electrode material that has good adhesion to the nano-SEBS film, and because SEBS has very good stretchability, the electrode can be stretchable, a non-stretchable flexible soft electrode, or a hard electrode.

[0075] In step three, the conductive fiber structure finally obtained has a precisely controlled "exposure-encapsulation" area distribution. Most of the surface area of ​​the conductive fiber is covered by a highly flexible, highly elastic and biocompatible SEBS film, and only functional exposure windows are retained at pre-set positions to achieve specific functions such as electrode contact, electrical signal acquisition or electrical stimulation output.

[0076] The selective encapsulation method of flexible stretchable conductive fibers proposed in this application has been systematically experimentally verified in multiple groups of samples, and the results show that this method has good process stability and application effect. Through the process means provided in this application, the non-functional area 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, and the encapsulation area has good tensile resistance and bending adaptability, without significantly affecting the overall flexibility and mechanical properties. The monitoring point area remains exposed, the conductive performance is not disturbed in any way, the electrical signal transmission is stable, and the noise level is low, meeting the requirements for high-quality acquisition of electrophysiological signals.

[0077] In addition, by optimizing the selection of packaging materials and the control of the packaging process, this application effectively achieves the goal of functional differentiation of different areas of the conductive fiber: that is, conductivity is maintained only in the preset monitoring area, and 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 shedding, uneven packaging, and difficulty in accurately controlling monitoring points in traditional packaging processes, but also achieves a high degree of matching between the packaging structure and the conductive fiber in terms of mechanical properties. The packaging structure remains intact under complex deformation conditions such as multiple stretching, bending, and compression, without cracking, peeling, or packaging failure.

[0078] Compared with the prior art, the fiber electrode packaging method provided in this application has the following advantages: 1. Precise patterning capabilities.

[0079] This application uses CAD design + laser cutting mask to precisely control the SEBS film adhesion area and realize exposure windows at predetermined positions, which is suitable for applications such as functional electrodes and exposed contacts.

[0080] 2. Low temperature non-destructive process.

[0081] This application does not require high temperature, solvent volatilization or light curing during the entire packaging process, which greatly protects the conductive properties and structural integrity of the conductive fiber and is particularly suitable for temperature-sensitive materials (such as liquid metal composite fibers).

[0082] 3. Nanoscale ultra-thin encapsulation layer.

[0083] The thickness of the SEBS film of the present application can be controlled at the nanometer level (tens to hundreds of nanometers), and the thickness or stiffness of the fiber is hardly increased after encapsulation, maintaining its good stretchability and skin-fitting properties.

[0084] 4. Easy to operate and can be implemented in batches.

[0085] The process of this application is simple, does not require expensive equipment, can be completed under standard laboratory conditions, and has the potential to be promoted to batch processing of multiple fibers.

[0086] 5. Strong biocompatibility and wearable adaptability.

[0087] The SEBS material of the present application has good biocompatibility, stretchability and skin affinity, and is suitable for long-term wear and use, and is particularly suitable for human body signal acquisition or nerve stimulation application scenarios.

[0088] Based on the above technical solution, an embodiment of the present application provides a method for packaging a fiber electrode, which includes the following steps: first, preparing a PET mask template with a preset pattern; the PET mask template has an opening area that can be used to limit the local formation of a nano-scale film; then, placing the PET mask template with a 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 preparing a mask template with a nano-scale SEBS film; then, using two mask templates with nano-scale SEBS films to sandwich the conductive fiber from the upper and lower sides respectively, and using the self-adhesiveness of the SEBS film to achieve stable bonding between the film and the conductive fiber, thereby constructing a sandwich packaging structure; then, gradually peeling the SEBS film 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 taken out as a whole from the two mask templates with nano-scale SEBS films to obtain a stretchable conductive fiber structure with local insulating coating and functional exposure window.

[0089] This application provides a fiber electrode packaging method that utilizes a customized mask template to prepare a nanoscale elastic insulating SEBS (styrene-ethylene-butylene-styrene block copolymer) film. This method achieves selective insulation packaging of non-exposed areas through a double-layer membrane wrapping structure. This packaging method, proposed in this application, precisely defines and effectively protects the functional regions of flexible conductive fibers, achieving the technical goals of structural flexibility, stable conductivity, simple processing, and strong adaptability. The method has promising application prospects and promotional value, and is particularly suitable for wearable and implantable electrophysiological systems that require high structural flexibility and insulation reliability.

[0090] Those skilled in the art will appreciate that the above-described embodiments are specific examples for implementing the present application, and that in actual applications, various changes in form and detail may be made thereto without departing from the spirit and scope of the present application. Any person skilled in the art may make changes and modifications without departing from the spirit and scope of the present application. Therefore, the scope of protection of the present application shall be subject to the scope defined in the claims.

Claims

1. A method for packaging a fiber electrode, characterized in that: The following steps are involved: A PET mask template with a preset pattern is prepared; the PET mask template has an opening area that can be used to limit the local formation of the nano-scale film; Placing a PET mask template with a preset pattern on the water surface where the SEBS film is formed, ensuring that the opening area of ​​the PET mask template is in full contact with the SEBS film and that the SEBS film is firmly attached to the pattern area of ​​the PET mask template, thereby obtaining a mask template with a nano-scale SEBS film; Two masks with nano-SEBS films are used to sandwich the conductive fibers from the top and bottom, respectively. The self-adhesive nature of the SEBS films ensures a stable bond between the films and the conductive fibers, creating a sandwich packaging structure. Subsequently, the SEBS films are gradually peeled off the PET masks, allowing them to firmly adhere to the conductive fiber surface and gradually detach from the masks. The encapsulated conductive fiber is taken out as a whole from two mask templates with nano-scale SEBS films to obtain a stretchable conductive fiber structure with local insulating coating and functional exposure windows.

2. The fiber electrode packaging method according to claim 1, characterized in that: Prepare a PET mask template with a preset pattern, including: Positioning the exposed area on the conductive fiber according to the functional design of the conductive fiber to be encapsulated; Drawing a pattern of a mask template based on the position, size, and shape of the exposed area on the conductive fiber to subsequently determine the patterned forming area of ​​the nano-SEBS film; The pattern of the mask template is imported into the UV laser marking system, and the UV laser marking machine is used to perform high-precision pattern cutting on the high-transparency PET film to produce a PET mask template with a preset pattern.

3. The fiber electrode packaging method according to claim 1, characterized in that: The water surface where the SEBS film is formed includes: Prepare clean culture dishes that match the package size and fill them with deionized water, ensuring that the water surface is flat and free of bubbles and impurities; A 5%-20% mass fraction SEBS toluene solution was added dropwise to the center of a culture dish containing clean water. The solution quickly spread on the water surface and formed a stable nanoscale SEBS film.

4. The fiber electrode packaging method according to claim 1, characterized in that: SEBS film is a styrene-ethylene-butylene-styrene block copolymer film.

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

6. The fiber electrode packaging method according to claim 1, characterized in that: A mask template with a nano-scale SEBS film is prepared, comprising: After placing a PET mask template with a preset pattern on the water surface where the SEBS film is formed, tweezers are used to remove the SEBS film on the excess area outside the PET mask template, ensuring that the SEBS film layer is retained only in the required opening area, thereby obtaining a mask template with the pattern area covered with a nano-scale SEBS film to achieve functional coating of the local area of ​​the conductive fiber.

7. The fiber electrode packaging method according to claim 1, characterized in that: Two mask templates with nano-SEBS films are used to sandwich the conductive fibers from the upper and lower sides. The self-adhesive nature of the SEBS films is utilized to achieve stable bonding between the films and the conductive fibers, thus constructing a sandwich packaging structure, including: Two mask templates with nano-scale SEBS films are used as the upper and lower layers of the package respectively; Lay the conductive fiber flat on the SEBS film surface of the underlying mask template, ensuring that the target exposure area of ​​the conductive fiber is accurately aligned with the pattern opening on the mask template during positioning; Subsequently, the mask template serving as the upper layer is aligned with the mask template of the lower layer from above and covers the conductive fibers so that the conductive fibers are located between the two layers of SEBS films to construct a sandwich packaging structure.

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

9. The fiber electrode packaging method according to claim 1, characterized in that: The packaging material in the sandwich packaging structure is a nanometer-thick thin film material with good biocompatibility and good insulation.

10. The fiber electrode packaging method according to claim 1, characterized in that: In a stretchable conductive fiber structure with local insulating coating and functional exposure windows, the surface area of ​​the conductive fiber is coated with a highly flexible, highly elastic and biocompatible SEBS film, and only the functional exposure window is retained in the pre-set opening area to realize the functions of electrode contact, electrical signal acquisition or electrical stimulation output.

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