A flexible electrocardiogram sensing electrode system based on textile materials

Abstract

This invention discloses a flexible ECG sensing electrode system based on textile materials, belonging to the field of ECG signal acquisition technology. It solves the problems of insufficient breathability and skin-friendliness, weak adhesion of the conductive layer, poor bending resistance, and high skin contact impedance of existing flexible dry electrodes. The system includes a flexible ECG sensing electrode body and an ECG acquisition and transmission module, which are electrically connected. In this embodiment, the synergistic cooperation of the fabric substrate, TPU hot-pressed stabilizing layer, silver nanowire layer, and low-impedance gel layer achieves a balance of flexibility, breathability, high adhesion, low impedance, and biocompatibility. Furthermore, the accompanying low-power wireless acquisition and transmission BLE module eliminates the constraints of wired connections, supporting real-time amplification, filtering, analog-to-digital conversion, preprocessing, and Bluetooth Low Energy transmission of ECG data. This facilitates connection to smart terminals and expands applications to multiple scenarios such as home, sports, and medical monitoring.

Description

Technical Field

[0001] This invention belongs to the field of electrocardiogram (ECG) signal acquisition technology, specifically relating to a flexible ECG sensing electrode system based on textile materials. Background Technology

[0002] Electrocardiogram (ECG) signals are key physiological signals reflecting the electrophysiological activity of the heart. They can directly demonstrate the depolarization and repolarization processes of myocardial cells, and have irreplaceable clinical value for the early screening and continuous monitoring of cardiovascular diseases such as arrhythmias, myocardial ischemia, and myocardial infarction. With the increasing aging of the population and the continuous rise in the incidence of cardiovascular diseases, ECG monitoring is rapidly expanding from traditional in-hospital diagnosis to scenarios such as long-term out-of-hospital monitoring, home health management, and exercise rehabilitation monitoring. This places higher demands on the comfort, portability, and long-term stability of ECG acquisition devices.

[0003] Currently, traditional ECG acquisition electrodes are still mainly Ag / AgCl wet electrodes. These electrodes rely on conductive paste or conductive gel as the skin-electrode interface coupling medium. Although they have low initial contact impedance and good signal quality, they have the following inherent drawbacks: Risks of skin irritation and allergies: The chloride ions and chemical additives in the conductive paste can easily cause adverse reactions such as skin redness, swelling, itching, and contact dermatitis. Long-term wear (more than 24 hours) can lead to overhydration of the stratum corneum and damage to the barrier function. It is not suitable for long-term monitoring by elderly patients and people with sensitive skin.

[0004] Motion artifacts and easy detachment: The conductivity of the gel layer decreases significantly after drying on the skin, and the mechanical coupling between the electrode and the skin depends on the adhesive layer. Motion artifacts are easily generated when the limbs move, sweat, or the body position changes, and even electrode detachment and displacement may occur, resulting in signal interruption or baseline drift, which seriously restricts the reliability of exercise ECG monitoring and Holter monitoring.

[0005] The constraints of wired connections: Traditional ECG acquisition systems often use shielded wires to connect electrodes to the acquisition host, which leads to tangled cables, restricted movement, poor wearing experience, and the lead wires are prone to generating additional noise due to traction. They cannot meet the seamless monitoring needs in free scenarios such as home, office, and sports.

[0006] To overcome the shortcomings of traditional wet electrodes, dry and semi-dry electrodes based on flexible electronics technology have become a research hotspot in recent years. Existing flexible ECG electrodes mainly use polymer films such as polyethylene terephthalate (PET) and polyimide (PI) as substrates. Although they have a certain degree of mechanical flexibility, they still have significant shortcomings in practical wearable applications. Insufficient breathability and skin-friendliness: The PET / PI film base is almost non-breathable. Long-term contact with the skin can lead to local sweat accumulation, stuffiness and discomfort. In addition, the material itself lacks the soft touch of fabric and has poor conformability to the curves of the human body, making it difficult to achieve seamless integration with everyday clothing, resulting in low user acceptance.

[0007] Weak adhesion and poor bending resistance of conductive layer: Some textile-based flexible electrodes directly coat the conductive material (conductive polymer, metal coating or carbon-based material) onto the fabric surface. Due to the low surface energy and rough microstructure of the fabric fibers, the interfacial bonding force between the conductive layer and the substrate is weak. During repeated bending, rubbing and washing, the conductive layer is prone to cracking, peeling or a sharp increase in resistance, resulting in signal acquisition failure and short service life.

[0008] High skin contact impedance: There is a lack of effective ion-conducting medium between the dry electrode and the skin. An oxide layer and air gap are easily formed at the interface, resulting in a contact impedance that is significantly higher than that of the wet electrode (usually reaching tens to hundreds of kΩ). High contact impedance not only reduces the signal amplitude and introduces thermal noise, but also makes the electrode more sensitive to power frequency electromagnetic interference and motion artifacts, which seriously degrades the signal-to-noise ratio and waveform fidelity of the ECG signal.

[0009] Low system integration and insufficient wireless connectivity: Existing textile-based electrodes mostly focus on verifying the conductivity of materials, lacking system-level integration design with low-power signal conditioning and wireless transmission modules. This makes it difficult to directly form a complete wearable ECG monitoring terminal, thus limiting its industrial application. In summary, traditional Ag / AgCl wet electrodes suffer from skin irritation, easy detachment, and wired constraints, making them unsuitable for long-term wearable monitoring. Meanwhile, existing flexible dry electrodes still face significant technical bottlenecks in areas such as breathability, conductive layer durability, skin contact impedance, and system integration. To address these issues, we propose a flexible ECG sensing electrode system based on textile materials. Summary of the Invention

[0010] The purpose of this invention is to address the shortcomings of existing technologies by providing a flexible ECG sensing electrode system based on textile materials, which solves the problems of insufficient breathability and skin-friendliness, weak adhesion of the conductive layer, poor bending resistance, and high skin contact resistance of existing flexible dry electrodes.

[0011] The present invention is implemented as follows: a flexible electrocardiogram (ECG) sensing electrode system based on textile materials, the flexible ECG sensing electrode system based on textile materials includes a flexible ECG sensing electrode body and an ECG acquisition and transmission module, the flexible ECG sensing electrode body and the ECG acquisition and transmission module are electrically connected. The flexible ECG sensing electrode body comprises, from bottom to top: a fabric substrate, a TPU film layer, a silver nanowire layer, and a gel layer. The electrocardiogram acquisition and transmission module includes: The ADC module is used to amplify, filter, and convert the ECG signals acquired by the electrodes into analog-to-digital signals, and output the converted ECG signals. The MCU module is used to acquire the converted ECG signal, and to perform signal preprocessing, noise reduction, and data packaging. The BLE module is used to wirelessly transmit ECG data to the host computer, and Host computer; The ADC module is electrically connected to the flexible ECG sensing electrode body, the MCU module is electrically connected to both the ADC module and the BLE module, and the BLE module is communicatively connected to the host computer.

[0012] Preferably, the TPU film layer is hot-pressed onto the surface of the fabric substrate, the silver nanowire layer is fixed to the TPU film layer by thermal transfer, and the gel layer covers the surface of the silver nanowire layer.

[0013] Preferably, the fabric base is made of polyester fiber and has a thickness of 0.1-0.3 mm. It can also be cotton or cotton blended fabric. The fabric base has the characteristics of flexibility, breathability and washability.

[0014] Preferably, the thickness of the TPU film layer is 1-10 μm. When the TPU film layer is hot-pressed onto the surface of the fabric substrate, the hot-pressing temperature is 140-160℃, the hot-pressing pressure is 0.3-0.5 MPa, and the hot-pressing time is 20-60 s, so that the TPU film and the fabric substrate form a tight bonded interface without bubbles or curling edges.

[0015] Preferably, the silver nanowire layer is prepared using a combination of vacuum filtration film formation and thermal transfer process. The silver nanowire layer exhibits uniform conductivity, bend resistance, and low contact resistance. The preparation method of the silver nanowire layer includes: To prepare a polytetrafluoroethylene (PTFE) filter membrane, the PTFE filter membrane was treated with oxygen plasma to improve its surface hydrophilicity. The polydimethylsiloxane (PDMS) main agent and curing agent were mixed at a mass ratio of 10:1, screen-printed onto the surface of a tetrafluoroethylene filter membrane to form a mask, and cured at 100°C for 10 min. Silver nanowires were vacuum filtered onto a masked tetrafluoroethylene filter membrane to form a pre-defined conductive pattern of silver nanowires. The tetrafluoroethylene filter membrane with silver nanowire conductive pattern was hot-pressed onto the surface of the TPU film layer at a temperature of 150°C and a time of 20 seconds. After peeling off the filter membrane, the TPU film is heat-annealed at 150°C for 5 minutes to melt and encapsulate the silver nanowires, thus obtaining a silver nanowire layer, which enhances the mechanical stability and bending resistance of the conductive network.

[0016] Preferably, the gel layer comprises the following raw materials in parts by weight: 5 parts of 13wt% CNT-COOH aqueous solution, 1.2 parts of polyether F127, 1.3 parts of deionized water, and 2.5 parts of Ecoflex0030; wherein, Ecoflex0030 is medical-grade platinum-cured silicone rubber, and Ecoflex0030 is formulated in a 1:1 weight ratio of components A and B, and component A includes vinyl-terminated polydimethylsiloxane and platinum catalyst (Pt complex), and component B includes hydrosilicone oil and inhibitor. Component B is used to provide Si-H bonds for addition reactions with vinyl groups, and component A is used to provide active sites (vinyl groups) and catalytic centers for crosslinking reactions.

[0017] Preferably, the method for preparing the gel layer includes: Polyether F127 was dissolved in deionized water under ice-water bath conditions and stirred until a clear solution was obtained to obtain an aqueous solution of polyether F127. Add CNT-COOH aqueous solution to polyether F127 aqueous solution and stir for 10 min until uniformly dispersed to obtain polyether F127-CNT-COOH blend; Add premixed defoaming Ecoflex0030 to the polyether F127-CNT-COOH blend and stir for 15 min to obtain the gel compound solution; The gel compound solution was defoamed under vacuum for 20 minutes at room temperature; The vacuum-de-bubbled gel compound solution was injected into a mold and cured at 38°C for 2 hours to a semi-cured state to obtain a semi-cured gel. The semi-cured gel was bonded to the surface of the silver nanowire layer to complete the assembly of the flexible ECG sensing electrode body.

[0018] Preferably, the method for fabricating the flexible ECG sensing electrode system based on textile materials includes: S10, Fabric base pretreatment: Select polyester fiber, cotton or cotton blend fabric with a thickness of 0.1mm-0.3mm as the fabric base, cut according to the design size, clean and remove impurities, and dry for later use. S20, TPU film layer hot pressing, a TPU film with a thickness of 1-10μm is covered on the surface of the fabric substrate, and a hot press is used to hot press for 20s-60s at 140-160℃ and 0.3-0.5MPa. After cooling to room temperature, a tightly bonded composite substrate is formed. S30, Preparation and thermal transfer of silver nanowire layers; S40, Gel layer preparation and bonding: The gel layer is bonded to the surface of the silver nanowire layer to complete the preparation of the flexible ECG sensing electrode body. S50, system integration, connects the prepared flexible ECG sensing electrode body with the ADC module, MCU module, and BLE module to assemble a complete ECG acquisition and transmission module, and establishes a wireless communication link with the host computer to form a wearable flexible ECG sensing electrode system based on textile materials.

[0019] Compared with the prior art, the embodiments of this application have the following main advantages: In this embodiment of the invention, the synergistic combination of a fabric substrate, a TPU heat-pressed stabilizing layer, a silver nanowire layer, and a low-impedance gel layer achieves a balance of flexibility, breathability, high adhesion, low impedance, and biocompatibility. The textile substrate imparts skin-friendly and breathable properties to the electrodes, allowing for seamless integration with clothing and meeting long-term wear requirements. The TPU film layer significantly enhances the interfacial bonding force of the silver nanowire layer, ensuring stable conductivity of the electrodes even after repeated bending and washing. The silver nanowire layer provides a low-impedance, low-noise continuous conductive path, effectively improving the clarity and fidelity of ECG signal acquisition. The gel layer further reduces skin contact impedance, improving signal quality. The gel layer achieves a soft, skin-friendly, non-irritating, and non-allergenic interface through a synergistic formulation of carbon nanotubes, polyether F127, and Ecoflex. The accompanying low-power wireless acquisition and transmission BLE module eliminates the constraints of wires, supporting real-time amplification, filtering, analog-to-digital conversion, preprocessing, and Bluetooth Low Energy transmission of ECG data. This facilitates connection with smart terminals and expands applications to multiple scenarios such as home, sports, and medical monitoring. Furthermore, key processes such as hot-pressing, vacuum filtration film formation, and thermal transfer are mature and controllable, facilitating large-scale production. The products exhibit good consistency and low cost, providing a practical technical solution for the industrialization and promotion of flexible wearable ECG monitoring technology.

[0020] In this embodiment of the invention, the silver nanowire layer is prepared using a gradient process combining vacuum filtration and thermal transfer. First, oxygen plasma treatment of the PTFE filter membrane enhances its surface hydrophilicity, ensuring uniform spreading and dense film formation of the silver nanowire dispersion. Combined with the screen printing patterned design of the PDMS mask, the morphology and size of the conductive regions can be precisely controlled, achieving customized distribution of the conductive network. The vacuum filtration process causes the silver nanowires to be oriented and stacked on the filter membrane surface, forming a continuous and uniform conductive pathway. Compared to spraying and coating processes, this effectively avoids the aggregation and uneven distribution of silver nanowires, ensuring consistent conductivity from the source. Subsequent... Patterned silver nanowire layers are completely transferred to the surface of a TPU film by short-time hot pressing at 150℃. Then, the TPU is partially melted and encapsulated by the silver nanowires through heat annealing at the same temperature. This achieves a strong interfacial bond between the silver nanowires and the TPU layer, solving the problems of easy detachment and poor bending resistance of the conductive layer of ordinary textile-based electrodes. At the same time, it retains the low intrinsic impedance of the silver nanowires themselves. The resulting conductive network has the characteristics of high conductivity uniformity, low contact resistance, and resistance to repeated bending. Even after multiple washing and stretching deformations, it can maintain stable conductivity, providing a reliable conduction basis for low-noise and high-fidelity acquisition of electrocardiogram signals. Attached Figure Description

[0021] Figure 1 A schematic diagram of the integration of the flexible ECG sensing electrode body with clothing provided in an embodiment of the present invention is shown.

[0022] Figure 2 This is a schematic diagram of the structure of the flexible electrocardiogram sensing electrode body provided by the present invention.

[0023] Figure 3 This is a schematic diagram of the electrocardiogram acquisition and transmission module provided by the present invention.

[0024] Figure 4 A schematic diagram illustrating the fabrication process of a flexible electrocardiogram sensing electrode system based on textile materials is shown.

[0025] In the diagram: 1-Gel layer, 2-Silver nanowire layer, 3-TPU film layer, 4-Fabric substrate, 5-ADC module, 6-MCU module, 7-BLE module, 8-Host computer. Detailed Implementation

[0026] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs; the terminology used herein in the specification of the application is for the purpose of describing particular embodiments only and is not intended to be limiting of the application; the terms "comprising" and "having," and any variations thereof, in the specification, claims, and foregoing drawings of this application are intended to cover non-exclusive inclusion. The terms "first," "second," etc., in the specification, claims, or foregoing drawings of this application are used to distinguish different objects, not to describe a particular order.

[0027] In this document, the term "embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment mutually exclusive with other embodiments. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0028] Traditional Ag / AgCl wet electrodes suffer from skin irritation, easy detachment, and wired constraints, making them unsuitable for long-term wearable monitoring. Existing flexible dry electrodes still face significant technical bottlenecks in areas such as breathability, conductive layer durability, skin contact impedance, and system integration. To address these issues, we propose a flexible ECG sensing electrode system based on textile materials. In short, the system comprises a flexible ECG sensing electrode body and an ECG acquisition and transmission module, which are electrically connected. The flexible ECG sensing electrode body, from bottom to top, includes: a fabric substrate 4, a TPU film layer 3, a silver nanowire layer 2, and a gel layer 1. The ECG acquisition and transmission module includes an ADC module 5, an MCU module 6, a BLE module 7, and a host computer 8. In this embodiment of the invention, the synergistic cooperation of the fabric substrate 4, the TPU hot-pressing stabilizing layer, the silver nanowire layer 2, and the low-impedance gel layer 1 achieves a balance of flexibility, breathability, high adhesion, low impedance, and biocompatibility. The textile substrate imparts skin-friendly and breathable properties to the electrodes, allowing for seamless integration with clothing and meeting long-term wear requirements. The TPU film layer 3 significantly enhances the interfacial bonding force of the silver nanowire layer 2, ensuring that the electrodes maintain stable conductivity even after repeated bending and washing. The silver nanowire layer 2 provides a low-impedance, low-noise continuous conductive path, effectively improving the clarity and fidelity of ECG signal acquisition. The gel layer 1 further reduces skin contact impedance and improves signal quality. Meanwhile, the gel layer 1 achieves a soft, skin-friendly, non-irritating, and non-allergenic interface through the synergistic formulation of carbon nanotubes, polyether F127, and Ecoflex. The matching low-power wireless acquisition and transmission BLE module 7 eliminates the constraints of wires, supports real-time amplification, filtering, analog-to-digital conversion, preprocessing, and Bluetooth low-power transmission of ECG data, facilitating connection with smart terminals and expanding applications to multiple scenarios such as home, sports, and medical monitoring. In addition, key processes such as hot-pressing, vacuum filtration film formation, and thermal transfer are mature and controllable, easy to scale up production, and produce products with good consistency and low cost, providing a practical technical solution for the industrialization and promotion of flexible wearable ECG monitoring technology.

[0029] This invention provides a flexible electrocardiogram (ECG) sensing electrode system based on textile materials, such as... Figures 1-2 As shown, the flexible ECG sensing electrode system based on textile materials includes a flexible ECG sensing electrode body and an ECG acquisition and transmission module, which are electrically connected. In this embodiment of the invention, the fabric substrate 4 is made of polyester fiber and has a thickness of 0.1-0.3 mm. It can also be cotton or cotton blended fabric. The fabric substrate 4 has the characteristics of flexibility, breathability and washability.

[0030] The thickness of the TPU film layer 3 is 1-10μm. When the TPU film layer 3 is hot-pressed onto the surface of the fabric substrate 4, the hot-pressing temperature is 140-160℃, the hot-pressing pressure is 0.3-0.5MPa, and the hot-pressing time is 20-60s, so that the TPU film and the fabric substrate 4 form a tight bonded interface without bubbles or curling edges.

[0031] The flexible ECG sensing electrode body comprises, from bottom to top: a fabric substrate 4, a TPU film layer 3, a silver nanowire layer 2, and a gel layer 1. The TPU film layer 3 is hot-pressed onto the surface of the fabric substrate 4, the silver nanowire layer 2 is fixed to the TPU film layer 3 by thermal transfer, and the gel layer 1 covers the surface of the silver nanowire layer 2.

[0032] in, Figure 1 This diagram illustrates the integration of the flexible ECG sensing electrode body with clothing according to an embodiment of the present invention. Figure 1 The image shows a T-shirt with multiple flexible ECG sensing electrodes integrated at preset positions on the front and shoulders. Each electrode is a rectangular patch and is electrically connected to an ECG acquisition and transmission module located at the hem or side seam of the garment via conductive wires. Each electrode, from bottom to top, includes a fabric substrate 4, a TPU film layer 3, a silver nanowire layer 2, and a gel layer 1. The gel layer 1 faces the skin to ensure a comfortable fit and low-impedance contact. The ECG acquisition and transmission module incorporates an ADC module 5, an MCU module 6, and a BLE module 7 to amplify, filter, convert analog to digital, preprocess, and wirelessly transmit ECG signals, enabling real-time communication with a host computer 8.

[0033] like Figure 3 As shown, the ECG acquisition and transmission module includes: ADC module 5 (analog-to-digital converter module) is used to amplify, filter and convert the ECG signal acquired by the electrodes to analog-to-digital, and output the converted ECG signal. ADC module 5 is a low-noise ECG dedicated analog-to-digital converter chip with built-in instrumentation amplifier and RC filter circuit. The common-mode rejection ratio is not less than 80dB, which is used to suppress power frequency interference and motion artifacts. MCU module 6 (microcontroller module) is used to acquire the converted ECG signal, perform ECG signal preprocessing, noise reduction and data packaging; BLE module 7 (Bluetooth Low Energy module) is used to wirelessly transmit ECG data to the host computer 8. BLE module 7 adopts the Bluetooth Low Energy communication protocol, conforms to Bluetooth 5.0 and above standards, supports short-range wireless transmission with a transmission distance of not less than 10 meters, and facilitates communication connections with the host computer 8, such as smartphones, tablets, or medical monitoring terminals. Host computer 8; The ADC module 5 is electrically connected to the flexible ECG sensing electrode body, the MCU module 6 is electrically connected to the ADC module 5 and the BLE module 7 respectively, and the BLE module 7 is communicatively connected to the host computer 8.

[0034] In this embodiment of the invention, the synergistic cooperation of the fabric substrate 4, the TPU hot-pressing stabilizing layer, the silver nanowire layer 2, and the low-impedance gel layer 1 achieves a balance of flexibility, breathability, high adhesion, low impedance, and biocompatibility. The textile substrate imparts skin-friendly and breathable properties to the electrodes, allowing for seamless integration with clothing and meeting long-term wear requirements. The TPU film layer 3 significantly enhances the interfacial bonding force of the silver nanowire layer 2, ensuring that the electrodes maintain stable conductivity even after repeated bending and washing. The silver nanowire layer 2 provides a low-impedance, low-noise continuous conductive path, effectively improving the clarity and fidelity of ECG signal acquisition. The gel layer 1 further reduces skin contact impedance and improves signal quality. Meanwhile, the gel layer 1 achieves a soft, skin-friendly, non-irritating, and non-allergenic interface through the synergistic formulation of carbon nanotubes, polyether F127, and Ecoflex. The matching low-power wireless acquisition and transmission BLE module 7 eliminates the constraints of wires, supports real-time amplification, filtering, analog-to-digital conversion, preprocessing, and Bluetooth low-power transmission of ECG data, facilitating connection with smart terminals and expanding applications to multiple scenarios such as home, sports, and medical monitoring. In addition, key processes such as hot-pressing, vacuum filtration film formation, and thermal transfer are mature and controllable, easy to scale up production, and produce products with good consistency and low cost, providing a practical technical solution for the industrialization and promotion of flexible wearable ECG monitoring technology.

[0035] In a further preferred embodiment of the present invention, the silver nanowire layer 2 is prepared by a combination of vacuum filtration film formation and thermal transfer process. The silver nanowire layer 2 has uniform conductivity, bend resistance, and low contact resistance. The preparation method of the silver nanowire layer 2 includes: S101, Preparation of polytetrafluoroethylene (PTFE) filter membrane: The polytetrafluoroethylene (PTFE) filter membrane is treated with oxygen plasma to improve its surface hydrophilicity; S102, the polydimethylsiloxane (PDMS) main agent and curing agent are mixed at a mass ratio of 10:1, screen printed on the surface of a tetrafluoroethylene filter membrane to form a mask, and cured at 100℃ for 10 min; wherein, the curing agent can be a hydrosilylation reaction crosslinking agent for polydimethylsiloxane (PDMS), which can undergo a hydrosilylation reaction with the main agent (PDMS prepolymer with vinyl end groups), so that the linear silicone oil molecules crosslink to form a three-dimensional network elastic solid, realizing the transformation of PDMS from liquid to solid state.

[0036] S103, silver nanowires are vacuum filtered on a masked tetrafluoroethylene filter membrane to form a preset silver nanowire conductive pattern. S104, the tetrafluoroethylene filter membrane with silver nanowire conductive pattern is hot-pressed onto the surface of TPU film layer 3. The hot-pressing temperature is 150℃ and the hot-pressing time is 20s. S105, after peeling off the filter membrane, is heat-annealed at 150℃ for 5 minutes to melt and encapsulate the silver nanowires in the TPU film, thus obtaining silver nanowire layer 2, which enhances the mechanical stability and bending resistance of the conductive network.

[0037] In this embodiment of the invention, the silver nanowire layer 2 is prepared using a gradient process combining vacuum filtration and thermal transfer. First, oxygen plasma treatment of the PTFE filter membrane enhances its surface hydrophilicity, ensuring uniform spreading and dense film formation of the silver nanowire dispersion. Combined with the screen printing patterned design of the PDMS mask, the morphology and size of the conductive areas can be precisely controlled, achieving customized distribution of the conductive network. The vacuum filtration process causes the silver nanowires to be oriented and stacked on the filter membrane surface, forming a continuous and uniform conductive pathway. Compared to spraying and coating processes, this effectively avoids the aggregation and uneven distribution of silver nanowires, ensuring consistent conductivity from the source. Subsequent... Patterned silver nanowire layer 2 is completely transferred to the surface of TPU film by short-time hot pressing at 150℃. Then, the silver nanowires are partially melted and wrapped by the TPU through heat annealing at the same temperature. This achieves a strong interfacial bond between the silver nanowires and the TPU layer, solving the problems of easy detachment and poor bending resistance of the conductive layer of ordinary textile-based electrodes. At the same time, it retains the low intrinsic impedance of the silver nanowires themselves. The resulting conductive network has the characteristics of high conductivity uniformity, low contact resistance, and resistance to repeated bending. Even after multiple washing and stretching deformation, it can still maintain stable conductivity, providing a reliable conduction basis for low-noise and high-fidelity acquisition of ECG signals.

[0038] In a further preferred embodiment of the present invention, the gel layer 1 comprises the following raw materials in parts by weight: 5 parts of 13wt% CNT-COOH aqueous solution, 1.2 parts of polyether F127, 1.3 parts of deionized water, and 2.5 parts of Ecoflex0030; wherein, Ecoflex0030 is medical-grade platinum-cured silicone rubber, and Ecoflex0030 is formulated in a 1:1 weight ratio of components A and B, wherein component A includes vinyl-terminated polydimethylsiloxane and a platinum catalyst (Pt complex), and component B includes hydrosilicone oil and an inhibitor. Component B is used to provide Si-H bonds for addition reactions with vinyl groups, and component A is used to provide active sites (vinyl groups) and catalytic centers for crosslinking reactions. The preparation method of the gel layer 1 includes: S201, under ice-water bath conditions, polyether F127 is dissolved in deionized water and stirred until a clear solution is obtained to obtain an aqueous solution of polyether F127; S202, add CNT-COOH aqueous solution to polyether F127 aqueous solution, stir for 10 min until uniformly dispersed to obtain polyether F127-CNT-COOH blend; wherein, CNT-COOH aqueous solution refers to the aqueous dispersion of carboxylated carbon nanotubes, which is used to maintain the intrinsic high conductivity of carbon nanotubes, while achieving stable dispersion in aqueous phase and strong interfacial bonding with gel matrix through carboxyl modification, ultimately endowing gel layer 1 with low impedance, high flexibility, and biocompatible conductive interface characteristics, and is a key material component for realizing low-noise signal acquisition of this flexible ECG electrode.

[0039] Add premixed defoaming Ecoflex0030 to the S203 polyether F127-CNT-COOH blend solution and stir for 15 min to obtain the gel compound solution; S204, the gel compound solution was defoamed under vacuum at room temperature for 20 minutes; S205, the vacuum-defoamed gel compound solution is injected into the mold and cured at 38℃ for 2 hours to a semi-cured state to obtain a semi-cured gel; S206, the semi-cured gel is bonded to the surface of the silver nanowire layer 2 to complete the assembly of the flexible ECG sensing electrode body.

[0040] In this embodiment of the invention, gel layer 1 achieves a balance between mechanical properties, electrical conductivity, and biocompatibility through multi-component synergistic design and gradient curing process: carboxylated carbon nanotubes (CNT-COOH) are used as conductive fillers, combined with polyether F127 amphiphilic block copolymer to construct a continuous conductive network, significantly reducing skin contact impedance and ensuring low-loss conduction of electrocardiogram signals; medical-grade Ecoflex is selected. Using 0030 silicone rubber as a flexible matrix, component A, vinyl-terminated polydimethylsiloxane, provides active sites for crosslinking reactions, while a platinum catalyst triggers the addition reaction. Component B, hydrosilicone oil, provides Si-H bonds as crosslinking points. Combined with inhibitors, the curing rate is precisely controlled, resulting in a gel with excellent tensile resilience and skin compatibility, providing a pressure-free and non-displaceable fit during wear. The preparation process employs low-temperature mixing in an ice-water bath to avoid high-temperature degradation of component activity. Combined with vacuum degassing and a 38°C semi-curing process, CNT aggregation is prevented, ensuring conductivity uniformity. Furthermore, the gel adheres to the silver nanowire layer 2 in a semi-fluid state, forming a stable bond with the electrode body after curing, preventing interface detachment. The resulting gel layer 1 is soft, skin-friendly, and poses no risk of allergies. It maintains stable low impedance characteristics in both dry and wet conditions, effectively suppressing motion artifacts and power frequency interference, significantly improving the signal-to-noise ratio of ECG signal acquisition and long-term wear comfort.

[0041] In a further preferred embodiment of the present invention, Figure 4A schematic diagram illustrating the fabrication process of a flexible ECG sensing electrode system based on textile materials is shown. The fabrication method of the flexible ECG sensing electrode system based on textile materials includes: S10, Fabric base 4 pretreatment: Select polyester fiber, cotton or cotton blend fabric with a thickness of 0.1mm-0.3mm as fabric base 4, cut according to design size, clean and remove impurities and dry for later use. S20, TPU film layer 3 hot-pressed bonding, a TPU film with a thickness of 1-10μm is covered on the surface of the fabric substrate 4, and hot-pressed for 20s-60s at 140-160℃ and 0.3-0.5MPa using a hot press, and then cooled to room temperature to form a tightly bonded composite substrate; S30, Preparation and thermal transfer of silver nanowire layer 2; S40, Gel layer 1 preparation and bonding: Gel layer 1 is bonded to the surface of silver nanowire layer 2 to complete the preparation of flexible ECG sensing electrode body. S50, system integration, electrically connects the prepared flexible ECG sensing electrode body with ADC module 5, MCU module 6, and BLE module 7 to assemble a complete ECG acquisition and transmission module, and establishes a wireless communication link with the host computer 8 to form a wearable flexible ECG sensing electrode system based on textile materials.

[0042] In this embodiment, the electrocardiogram (ECG) signal acquisition process is as follows: S301, the flexible ECG sensing electrode body is attached to the human body surface to collect simulated ECG signals; S302, the ECG signal is sent to ADC module 5 to complete amplification, filtering and analog-to-digital conversion; S303, the converted ECG signal enters MCU module 6 for baseline correction, noise reduction and data packaging; S304, ECG data is wirelessly transmitted to host computer 8 via BLE module 7; S305, the host computer 8 displays ECG waveforms, stores data, and can provide abnormal warnings. In summary, this invention provides a flexible ECG sensing electrode system based on textile materials. In this embodiment, through the synergistic cooperation of the fabric substrate 4, the TPU hot-pressed stabilizing layer, the silver nanowire layer 2, and the low-impedance gel layer 1, a unified approach of flexibility, breathability, high adhesion, low impedance, and biocompatibility is achieved. Furthermore, the textile substrate imparts skin-friendly and breathable properties to the electrode, allowing for seamless integration with clothing and meeting long-term wear requirements. The TPU film layer 3 significantly enhances the interfacial bonding force of the silver nanowire layer 2, ensuring that the electrode maintains stable conductivity even after repeated bending and washing. The silver nanowire layer 2 provides a low-impedance, low-noise continuous conductive path, effectively improving the clarity and fidelity of ECG signal acquisition. The gel layer 1 further... By reducing skin contact impedance and improving signal quality, the gel layer 1 achieves a soft, skin-friendly, non-irritating, and non-allergenic interface through the synergistic formulation of carbon nanotubes, polyether F127, and Ecoflex. The accompanying low-power wireless acquisition and transmission BLE module 7 eliminates the constraints of wires, supporting real-time amplification, filtering, analog-to-digital conversion, preprocessing, and Bluetooth Low Energy transmission of ECG data. This facilitates connection with smart terminals and expands applications to multiple scenarios such as home, sports, and medical monitoring. Furthermore, key processes such as hot-press bonding, vacuum filtration film formation, and thermal transfer are mature and controllable, facilitating large-scale production, resulting in good product consistency and low cost. This provides a practical technical solution for the industrialization and promotion of flexible wearable ECG monitoring technology.

[0043] It should be noted that, for the sake of simplicity, the foregoing embodiments are all described as a series of actions. However, those skilled in the art should understand that the present invention is not limited to the described order of actions, as some steps may be performed in other orders or simultaneously according to the present invention. Furthermore, those skilled in the art should also understand that the embodiments described in the specification are preferred embodiments, and the actions and modules involved are not necessarily essential to the present invention.

[0044] The above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit the scope of protection of the invention. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on these embodiments, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art can still combine, add, delete, or otherwise adjust the features of the various embodiments of the present invention according to the circumstances without conflict or creative effort, thereby obtaining different technical solutions that do not fundamentally depart from the concept of the present invention. These technical solutions also fall within the scope of protection of the present invention.

Claims

1. A flexible electrocardio sensing electrode system based on textile material, characterized in that, The system includes a flexible ECG sensing electrode body and an ECG acquisition and transmission module, which are electrically connected. The flexible ECG sensing electrode body comprises, from bottom to top: a fabric substrate, a TPU film layer, a silver nanowire layer, and a gel layer. The electrocardiogram acquisition and transmission module includes: The ADC module is used to amplify, filter, and convert the ECG signals acquired by the electrodes into analog-to-digital signals, and output the converted ECG signals. The MCU module is used to acquire the converted ECG signal, and to perform signal preprocessing, noise reduction, and data packaging. The BLE module is used to wirelessly transmit ECG data to the host computer, and Host computer; The ADC module is electrically connected to the flexible ECG sensing electrode body, the MCU module is electrically connected to both the ADC module and the BLE module, and the BLE module is communicatively connected to the host computer.

2. The flexible electrocardio sensing electrode system based on textile material of claim 1, wherein: The TPU film layer is hot-pressed onto the surface of the fabric substrate, the silver nanowire layer is fixed to the TPU film layer by thermal transfer, and the gel layer covers the surface of the silver nanowire layer.

3. The flexible textile-based electrocardiogram sensing electrode system of claim 1, wherein: The fabric substrate is made of polyester fiber and has a thickness of 0.1-0.3 mm.

4. The flexible textile-based electrocardiogram sensing electrode system of claim 1, wherein: The thickness of the TPU film layer is 1-10μm. When the TPU film layer is hot-pressed onto the surface of the fabric substrate, the hot-pressing temperature is 140-160℃, the hot-pressing pressure is 0.3-0.5MPa, and the hot-pressing time is 20-60s.

5. The flexible textile-based electrocardiogram sensing electrode system of claim 1, wherein: The method for preparing the silver nanowire layer includes: To prepare a polytetrafluoroethylene (PTFE) filter membrane, the PTFE filter membrane was treated with oxygen plasma. The polydimethylsiloxane main agent and curing agent were mixed at a mass ratio of 10:1, screen-printed onto the surface of the tetrafluoroethylene filter membrane to form a mask, and cured at 100℃ for 10 min. Silver nanowires were vacuum filtered onto a masked tetrafluoroethylene filter membrane to form a pre-defined conductive pattern of silver nanowires. The tetrafluoroethylene filter membrane with silver nanowire conductive pattern was hot-pressed onto the surface of the TPU film layer at a temperature of 150°C and a time of 20 seconds. After peeling off the filter membrane, the TPU film is heat-annealed at 150°C for 5 minutes to melt and encapsulate the silver nanowires, thus obtaining a silver nanowire layer.

6. The flexible textile-based electrocardiogram sensing electrode system of claim 1, wherein: The gel layer comprises the following raw materials in parts by weight: 5 parts of 13wt% CNT-COOH aqueous solution, 1.2 parts of polyether F127, 1.3 parts of deionized water, and 2.5 parts of Ecoflex0030.

7. The flexible ECG sensing electrode system based on textile materials as described in claim 6, characterized in that: The method for preparing the gel layer includes: Polyether F127 was dissolved in deionized water under ice-water bath conditions and stirred until a clear solution was obtained to obtain an aqueous solution of polyether F127. Add CNT-COOH aqueous solution to polyether F127 aqueous solution and stir for 10 min until uniformly dispersed to obtain polyether F127-CNT-COOH blend; Add premixed defoaming Ecoflex0030 to the polyether F127-CNT-COOH blend and stir for 15 min to obtain the gel compound solution; The gel compound solution was defoamed under vacuum for 20 minutes at room temperature; The vacuum-de-bubbled gel compound solution was injected into a mold and cured at 38°C for 2 hours to a semi-cured state to obtain a semi-cured gel. The semi-cured gel was bonded to the surface of the silver nanowire layer to complete the assembly of the flexible ECG sensing electrode body.

8. The flexible ECG sensing electrode system based on textile materials as described in claim 7, characterized in that: The method for fabricating the flexible ECG sensing electrode system based on textile materials includes: S10, Fabric base pretreatment: Select polyester fiber with a thickness of 0.1mm-0.3mm as the fabric base, cut according to the design size, clean and remove impurities, and dry for later use. S20, TPU film layer hot pressing lamination, a TPU film with a thickness of 1-10μm is covered on the surface of the fabric substrate, and hot pressing is performed for 20s-60s at 140-160℃ and 0.3-0.5MPa using a hot press, and then cooled to room temperature to form a composite substrate; S30, Preparation and thermal transfer of silver nanowire layers; S40, Gel layer preparation and bonding: The gel layer is bonded to the surface of the silver nanowire layer to complete the preparation of the flexible ECG sensing electrode body. S50, system integration, connects the prepared flexible ECG sensing electrode body with the ADC module, MCU module, and BLE module to assemble a complete ECG acquisition and transmission module, and establishes a wireless communication link with the host computer to form a wearable flexible ECG sensing electrode system based on textile materials.

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