High-corrosion-resistance superfine silver fabric electrode and preparation and application thereof

Abstract

The invention discloses a high-corrosion-resistance superfine silver fabric electrode and a preparation method and application thereof.The high-corrosion-resistance superfine silver fabric electrode comprises an SYE conducting layer, an MPTS self-assembly anti-corrosion layer and an Ag / AgCl polarization / non-polarization composite structure layer, and the SYE conducting layer is obtained by sewing superfine silver tows on substrate fabric; the sewn superfine silver tows form an SYE conducting layer with continuous front and back surfaces, the surface of the SYE conducting layer is uniformly coated with an MPTS self-assembly anticorrosive layer, and the surface of the MPTS self-assembly anticorrosive layer is uniformly coated with an Ag / AgCl polarized / non-polarized composite structure layer. The ultra-fine silver wire bundle comprises the continuous SSYE conducting layers on the front face and the back face and the MPTS self-assembly anti-corrosion layer, the dual protection effect can be achieved, and even if the MPTS self-assembly anti-corrosion layer falls off after long-term abrasion, the ultra-fine silver wire bundle also has the excellent electrical performance. In addition, no harm is caused to human skin tissues or organs in the long-term physiological electric signal monitoring or electrical stimulation treatment process.

Description

Technical Field

[0001] The invention relates to the technical field of medical supplies, and in particular to a highly corrosion-resistant ultrafine silver wire fabric electrode and the preparation and application thereof. Background Art

[0002] Smart wearable clothing made of functional fibers has great clinical potential in the field of health monitoring. Real-time acquisition of physiological electrical signals through long-term wearable health acquisition systems can achieve timely diagnosis and prevention of physiological diseases. Bioelectric electrodes are sensors used to collect and record physiological electrical phenomena, which can realize the conversion from ionic conduction to electronic conduction in the human body.

[0003] Disposable gel electrodes are the gold standard electrodes used as bioelectric recording systems, but wet electrodes have the disadvantages of being easy to irritate the skin, and the gel electrolyte easily dries out over time, resulting in reduced signal quality, making them unsuitable for long-term acquisition. Therefore, researchers replaced wet electrodes with dry electrodes to meet the needs of long-term acquisition of physiological electrical signals. Fabric electrodes can unify the sensing and driving functions with the unique advantages of textiles such as breathability, softness, comfort, and easy integration with fabrics, which is particularly attractive for portable long-term continuous physiological electrical signal acquisition devices. Wearable electronic textiles will face various factors of damage during use, such as sweat corrosion, air oxidation, washing damage, long-term wear, etc. These damages will greatly affect the service life of wearable products and the reliability of signals. Therefore, it is necessary to improve the corrosion resistance and stability of fabric electrodes.

[0004] In recent years, there have been few studies on the durability of long-term monitoring of physiological electrical signal fabric electrodes at home and abroad. Patent CN101703399A introduces a method of using silver-plated polyamide conductive yarn to embroider a specific conductive area on a clothing substrate, and the purpose of collecting ECG signals is achieved through the contact between the conductive area and the skin. Patent CN201431463Y introduces the preparation of a wearable ECG electrode using CNTs / PET conductive yarns to form a woven structure through plain weaving of warp and weft. Patent CN104523267A introduces an embroidered flexible ECG electrode in which the conductive yarn on one side of the embroidery electrode is shortened to form multiple hairs. The electrode can achieve the purpose of ECG signal monitoring. The invention uses the end of the short conductive yarn and its bending stiffness to pierce the new stratum corneum, stabilize and reduce the contact impedance, and avoid signal interference caused by baseline drift and increased contact impedance. Patent CN109730673A introduces an embroidery electrode made of carbon-based fiber / polyester yarn. The electrocardiogram signals collected by this electrode can meet the needs of daily medical diagnosis, solving the problem of poor biocompatibility of existing textile flexible physiological electrical signal electrodes when used in the medical field, and meeting the cytotoxicity level requirements of medical devices.

[0005] The fabric electrodes disclosed in the above patents avoid the symptoms of itching, redness and swelling of the patient's skin caused by traditional electrodes, and can monitor ECG signals in the short term. However, they do not take into account the fact that the conductive material on the conductive yarn will fall off during use, and that sweat corrosion, air oxidation, washing damage, long-term wear and other problems during use may damage the durability and reliability of the electrodes. These problems are key issues that must be solved to achieve long-term physiological electrical signal monitoring. Summary of the invention

[0006] The purpose of the present invention is to provide a highly corrosion-resistant ultrafine silver wire fabric electrode and a preparation method thereof in view of the technical defects existing in the prior art.

[0007] Another object of the present invention is to provide a highly corrosion-resistant ultrafine silver wire fabric electrode for use in physiological electrical signal monitoring or electrical stimulation therapy.

[0008] The technical solution adopted to achieve the purpose of the present invention is:

[0009] A highly corrosion-resistant ultrafine silver wire fabric electrode, comprising an SSYE (ultrafine silver wire fabric electrode) conductive layer, an MPTS (trimercaptopropyltrimethoxysilane) self-assembled anti-corrosion layer and an Ag / AgCl polarized / non-polarized composite structure layer, wherein the SSYE conductive layer is obtained by sewing an ultrafine silver wire bundle onto a substrate fabric, wherein after sewing, the ultrafine silver wire bundle forms a continuous SSYE conductive layer on the front and back sides, and the surface of the SSYE conductive layer is uniformly coated with the MPTS self-assembled anti-corrosion layer, preferably, the surface of the SSYE conductive layer is uniformly coated with the MPTS self-assembled anti-corrosion layer by a chemical modification method, and the surface of the MPTS self-assembled anti-corrosion layer is uniformly coated with the Ag / AgCl polarized / non-polarized composite structure layer, preferably, the surface of the MPTS self-assembled anti-corrosion layer is uniformly coated with the Ag / AgCl polarized / non-polarized composite structure layer by a constant voltage deposition method.

[0010] In the above technical solution, the highly corrosion-resistant ultrafine silver wire fabric electrode is circular in shape, with a diameter of 10 to 30 mm and a thickness of 2 to 3 mm.

[0011] In the above technical solution, the substrate fabric is formed by hot-pressing high-density plain weave pure cotton woven fabric and adhesive interlining, the warp and weft density of the high-density plain weave cotton woven fabric is 500-700 threads / 10cm, and preferably, the adhesive interlining is a polyester-cotton blended fabric.

[0012] In the above technical solution, the SSYE conductive layer is formed by sewing ultrafine silver thread bundles twisted by ultrafine silver threads onto the base fabric through an embroidery process.

[0013] In the above technical solution, the ultrafine silver wire bundle is formed by twisting 16 to 28 ultrafine silver wires with a diameter of 0.030 to 0.090 mm, the diameter of the ultrafine silver wire bundle is 0.2 to 0.4 mm, and the electrical conductivity is 81836 to 111835.97 S / m.

[0014] In the above technical solution, the embroidery process is the Cantonese embroidery process, the embroidery stitches are spiral, the needle length is 1 to 3 mm, and the needle distance is 0.4 to 0.8 mm.

[0015] Another aspect of the present invention provides a method for preparing a highly corrosion-resistant ultrafine silver wire fabric electrode, comprising the following steps:

[0016] Step 1, preparation of SSYE conductive layer: sew twisted ultrafine silver thread bundles on the substrate fabric through embroidery process, so that the ultrafine silver thread bundles are continuously distributed on the front and back sides of the substrate fabric to obtain SSYE conductive layer. After the embroidery is completed, the SSYE conductive layer is hot pressed and cleaned, and impurities on the surface of the SSYE conductive layer are removed by ultrasonic wave, and then dried;

[0017] Step 2, preparation of MPTS self-assembled anticorrosion layer: placing the dried SSYE conductive layer obtained in step 1 in a 0.1-1 mol / L MPTS and acetone mixed solvent and stirring, then placing it in deionized water, taking it out, and drying it to obtain a trimercaptopropyltrimethoxysilane / ultrafine silver wire fabric electrode MPTS / SSYE;

[0018] Step 3, preparation of Ag / AgCl polarized / non-polarized composite structure layer: using the trimercaptopropyltrimethoxysilane / ultrafine silver wire fabric electrode MPTS / SSYE obtained in step 2 as a working electrode, the Ag / AgCl electrode as a reference electrode, and the platinum sheet electrode as a counter electrode, in an electrolyte solution, constant voltage deposition is performed on MPTS / SSYE by a constant voltage deposition method to form an Ag / AgCl polarized / non-polarized composite structure layer, and silver / silver chloride / trimercaptopropyltrimethoxysilane / ultrafine silver wire fabric electrode Ag / AgCl / MPTS / SSYE, i.e., a highly corrosion-resistant ultrafine silver wire fabric electrode.

[0019] In the above technical solution, the hot pressing temperature in step 1 is 120-130° C., and the hot pressing time is 15-30 seconds.

[0020] In the above technical solution, the electrolyte in step 3 is a sodium chloride solution with a mass fraction of 0.7-1.0%, and the constant voltage deposition parameters are a chlorination voltage of 0.5-2.5V and a chlorination time of 30-150s.

[0021] Another aspect of the present invention provides an application of the highly corrosion-resistant ultrafine silver wire fabric electrode in physiological electrical signal monitoring or electrical stimulation therapy.

[0022] Compared with the prior art, the present invention has the following beneficial effects:

[0023] The highly corrosion-resistant ultrafine silver wire fabric electrode of the present invention can be carried in smart wearable clothing for long-term real-time physiological electrical signal monitoring or electrical stimulation therapy. The ultrafine silver wire bundle is sewn to the fabric substrate to form a continuous SSYE conductive layer on the front and back sides, and the MPTS self-assembled anti-corrosion layer is deposited on the surface of the ultrafine silver wire bundle SSYE by chemical modification, which can play a dual protective role. Even after the MPTS self-assembled anti-corrosion layer falls off after long-term wear, the ultrafine silver wire bundle still has excellent electrical properties. Moreover, it will not cause damage to human skin tissue or organs during long-term physiological electrical signal monitoring or electrical stimulation therapy. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 Shown is a schematic diagram of the preparation of the highly corrosion-resistant ultrafine silver wire fabric electrode of the present invention.

[0025] Figure 2 The figure shows the mechanism diagram of the MPTS anticorrosion layer of the present invention. Among them, (a) is the optimized configuration of MPTS, (b) is the electrostatic potential diagram of MPTS, (c) is the frontier molecular orbital of MPTS, (d) is the adsorption system of MPTS and silver unit cell, and (e) is the adsorption energy of NaCl solution and silver unit cell and MPTS / silver unit cell respectively.

[0026] Figure 3 Shown are the electrochemical impedance spectra and equivalent circuit models of SPNE, SPCWE, SSYE, Ag / AgCl / MPTS / SPNE, Ag / AgCl / MPTS / SPCWE, and Ag / AgCl / MPTS / SSYE at the electrode electrolyte interface and electrode skin interface under the optimal antiseptic treatment and optimal chlorination treatment parameters.

[0027] Figure 4 The corrosion time-resistance change curves of SPNE, SPCWE, SSYEE, Ag / AgCl / MPTS / SPNE, Ag / AgCl / MPTS / SPCWE, and Ag / AgCl / MPTS / SSYE in sweat and the corrosion time-resistance change curves of SPNE, SPCWE, SSYEE, Ag / AgCl / MPTS / SPNE, Ag / AgCl / MPTS / SPCWE, and Ag / AgCl / MPTS / SSYE in Na 2 Corrosion time-resistance change curve in S solution.

[0028] Figure 5 Shown are ECG, EMG signal acquisition points and an electromyography test sleeve and compression stockings for neuromuscular electrical stimulation.

[0029] Figure 6 Shown are the electrocardiogram and P-QRS-T waveforms measured by disposable gel electrodes (Wet electrode).

[0030] Figure 7Shown are the ECG tests and analyses of SPNE, Ag / AgCl / MPTS / SPNE, SPCWE, Ag / AgCl / MPTS / SPCWE, SSYE, and Ag / AgCl / MPTS / SSYE under different conditions.

[0031] Figure 8 Shown are the EMG tests and EMG signal analysis of wet electrode, SPNE, Ag / AgCl / MPTS / SPNE, SPCWE, Ag / AgCl / MPTS / SPCWE, SSYE, and Ag / AgCl / MPTS / SSYE.

[0032] Fig. 9 Shown are the electrical stimulation tests and electrical stimulation signal analysis of wet electrode, SPNE, Ag / AgCl / MPTS / SPNE, SPCWE, Ag / AgCl / MPTS / SPCWE, SSYE, and Ag / AgCl / MPTS / SSYE. DETAILED DESCRIPTION

[0033] The present invention is further described in detail below in conjunction with specific embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0034] Example 1

[0035] Reference Figure 1 , a method for preparing a highly corrosion-resistant ultrafine silver wire fabric electrode, comprising the following steps:

[0036] Step 1, preparation of SSYE conductive layer: twisted ultrafine silver wire bundles are sewn on the substrate fabric through embroidery process to form continuous SSYE conductive layers on the front and back sides. After embroidery is completed, in order to improve the flatness and wearing comfort of the surface of the SSYE conductive layer, a hot press is used for hot pressing. The hot pressing temperature is 120°C and the hot pressing time is 15s. Hot pressing can adjust the uneven stitches that may appear during the manual embroidery process to uniform flatness. After hot pressing, the SSYE conductive layer is cleaned with anhydrous ethanol for 5 minutes, and then ultrasonicated with deionized water for 30 minutes to remove impurities on the surface of the SSYE fabric electrode, and then dried in a vacuum drying oven at 60°C for 1 hour.

[0037] Step 2, preparing a trimercaptopropyltrimethoxysilane (MPTS) self-assembled anticorrosion layer by chemical modification, placing the dried SSYE conductive layer obtained in step 1 in a 0.5 mol / L mixed solvent of MPTS and acetone and stirring for 45 min, then placing it in deionized water for 1 h, taking it out, and placing it in a vacuum drying oven at 60° C. for 1 h to completely dry it, thereby obtaining MPTS / SSYE;

[0038] In order to study the corrosion inhibition mechanism of MPTS on SSYE, the silver unit cell model, MPTS model, and 0.9% NaCl solution model were constructed in Materials Studio. The force field was set to COMPASS II and the electric field was set to 0 to simulate the physical conditions without the influence of external electric field. The Ag unit cell was cut into pieces with a thickness of 110 crystal face, and add 27.783144 around it The vacuum layer was added to avoid periodic boundary effects, and the model was expanded to a 7*6*1 supercell to simulate a larger surface area. After model optimization, the simulation parameters were set and molecular dynamics (MD) simulations were performed using the Forcite module. The electrostatic potential, frontier molecular orbitals, and adsorption energy of MPTS on the silver unit cell were analyzed, and the adsorption energy between the NaCl solution and the Ag crystal plane and the MPTS / Ag crystal plane was calculated to evaluate the corrosion inhibition performance of MPTS on the NaCl solution. Adsorption energy formula:

[0039] E ads =E A-B -(E A +E B )

[0040] Among them, E ads is the adsorption energy, E A-B is the total adsorption energy of all parts, E i is the adsorption energy of part A, E B is the adsorption energy of part B. In the first calculation, when calculating the adsorption energy of MPTS and the silver unit cell, A represents the silver unit cell and B represents MPTS. a-B represents the adsorption energy of the silver unit cell and MPTS as a whole; E A represents the adsorption energy of the silver unit cell; E B In the second calculation, when calculating the adsorption energy of NaCl solution on the Ag crystal surface, A represents the silver unit cell and B represents the NaCl solution. In this case, E A-B represents the overall adsorption energy between NaCl solution and Ag crystal surface; E A represents the adsorption energy of the silver unit cell; E B In the third calculation, when calculating the adsorption energy between the NaCl solution and the MPTS / Ag crystal surface, A represents the MPTS / Ag crystal surface and B represents the NaCl solution. At this time, E A-B represents the overall adsorption energy between NaCl solution and MPTS / Ag crystal surface; E A represents the adsorption energy of the MPTS / Ag surface; E B Represents the adsorption energy of the NaCl solution portion.

[0041] Reference Figure 2 The a in the figure is the stable configuration of the MPTS molecule after structural optimization. The electrostatic potential map reveals the charge distribution on the surface of the MPTS molecule, with different colors representing different potential areas. Figure 2 The red area in b represents a lower negative potential, and the blue area represents a higher negative potential. It can be found that the thiol (-SH) and trimethoxy (-OCH 3 ) show a high negative potential and strong nucleophilicity, which can provide lone pairs of electrons to participate in the reaction and are active sites. The highest occupied molecular orbital (HOMO) and the lowest unoccupied molecular orbital (LUMO) are key orbitals in molecular orbital theory. MPTS preservative molecules react chemically with the silver surface through these two orbitals. Figure 2 Figure c shows the density, energy, and energy gap of the HOMO and LUMO of MPTS in aqueous medium. The energy of HOMO (E HOMO ) is relatively low, indicating that the MPTS molecule easily loses electrons and reacts with the silver surface. LUMO ) is relatively high, indicating that MPTS molecules easily accept electrons from the silver surface and enhance the binding with silver. These two orbital processes complement each other and are conducive to enhancing the adsorption process. gap =E LUMO -E HOMO ) represents the energy required for electrons to transition from HOMO to LUMO. The energy gap of MPTS is relatively small at 0.368 eV, which means that it is easy for electrons to transition. Electron transfer and transition are the key to forming a stable anticorrosion layer, and they help to enhance the chemical bonding between MPTS and the silver surface. In the mixed preservative of MPTS and acetone, the thiol group (-SH) of MPTS acts as a ligand to provide the lone pair of electrons on its sulfur atom to form a silver-sulfur bond with the empty d orbital of the silver atom, providing a basis for the subsequent formation of a self-assembled anticorrosion layer. Afterwards, the water molecules in the deionized water act as nucleophiles to react with the silicon atoms in the MPTS molecules. During the nucleophilic reaction, the hydrogen atoms in the water molecules lose electrons, and the oxygen atoms of the water molecules provide lone pairs of electrons to form new silicon-oxygen covalent bonds with the empty d orbitals of the silicon atoms in MPTS. With the formation of the new silicon-oxygen bond, the original silicon-methoxy group (Si-OCH 3 ) bonds are broken, forming silanol groups (Si-OH) on the silicon atom and releasing methoxy groups (OCH 3) group. There may be oxygen atoms in some silanol groups (Si-OH) as ligands, using their lone pair electrons to form silver-oxygen coordination bonds with the empty d orbitals of silver atoms. This interaction helps to form more stable chemical adsorption on the silver surface. Condensation reactions will occur between silanol groups to form silicon-oxygen bonds (Si-O-Si). In this process, the hydrogen atom of one silanol group combines with the oxygen atom of another silanol group to form a water molecule. At the same time, a new silicon-oxygen bond is formed between the two silanol groups. Through the condensation reaction between silanol groups, a three-dimensional silicon-oxygen network structure can be formed, which enhances the stability of the self-assembled anti-corrosion layer by increasing intermolecular interactions, such as van der Waals forces and hydrogen bonds. Figure 2 In the figure d, MPTS is a stable adsorption configuration on the silver surface. It can be found that MPTS has a flat orientation. Compared with the vertical orientation, it can cover a larger surface area of ​​the silver surface and provide more corrosion protection. The adsorption energy of MPTS on the silver unit cell is -152.63 kcal / mol. This negative value means that the adsorption of MPTS on the silver surface is exothermic, and there is a strong chemical adsorption between them. This shows that MPTS helps to form a protective layer on the silver surface, thereby inhibiting the corrosion of the metal fabric electrode. Figure 2 Figure e shows that after MPTS is adsorbed on the silver surface, the binding force between the NaCl solution and MPTS / Ag is lower than the binding force between the NaCl solution and the Ag crystal cell. Without MPTS protection, the NaCl solution completely coated the silver surface after 1ps and began to corrode. After MPTS protection, the NaCl solution was completely coated on the silver surface after 50ps, which further confirms that MPTS can inhibit the direct contact between chloride ions and the silver surface, reduce the corrosion inhibition process, and improve the anti-corrosion performance of silver.

[0042] Step 3, prepare the Ag / AgCl polarized / non-polarized composite structure layer by constant voltage deposition method, adopt a three-electrode system, use the MPTS / SSYE obtained in step 2 as the working electrode, the commercial Ag / AgCl electrode as the reference electrode, the platinum electrode as the counter electrode, and the sodium chloride solution with a mass fraction of 0.9% as the electrolyte, and perform constant voltage deposition on MPTS / SSYE by constant voltage deposition method, the chlorination voltage of constant voltage deposition is 1.5V, and the chlorination time is 120s, and the Ag / AgCl polarized / non-polarized composite structure layer is formed on the surface of MPTS / SSYE to obtain Ag / AgCl / MPTS / SSYE, that is, a highly corrosion-resistant ultrafine silver wire fabric electrode. The prepared highly corrosion-resistant ultrafine silver wire fabric electrode is circular in shape, with a diameter of 20mm and a thickness of 3-4mm, and can perform long-term real-time monitoring and electrical stimulation of physiological electrical signals.

[0043] The substrate fabric is a fabric formed by hot-pressing high-density plain woven cotton fabric and adhesive lining, which is convenient for the moisture absorption and breathability of the electrode. The warp and weft density of the high-density plain woven cotton fabric is 600 threads / 10cm. The adhesive lining is a polyester-cotton blended fabric.

[0044] The ultrafine silver wire bundle is formed by twisting 22 ultrafine silver wires with a diameter of 0.060 mm. The diameter of the ultrafine silver wire bundle is 0.3 mm, and the electrical conductivity is 111835.97 S / m.

[0045] The embroidery technique is Cantonese embroidery technique, the embroidery stitches are spiral, the needle length is 2 mm, and the needle distance is 0.5 mm.

[0046] Comparative Example 1

[0047] The difference from Example 1 is that the ultrafine silver wire bundle with a diameter of 0.3 mm is replaced with silver-plated copper wire (SPCW), whose electrical conductivity is 136552.48 S / m, and the constant voltage deposition parameters for preparing the Ag / AgCl polarized / non-polarized composite structure layer are chlorination voltage 2.5 V and chlorination time 4 s, recorded as silver / silver chloride / trimercaptopropyltrimethoxysilane / silver-plated copper wire fabric electrode (Ag / AgCl / MPTS / SPCWE).

[0048] Comparative Example 2

[0049] Different from Example 1, the ultrafine silver wire bundle with a diameter of 0.3 mm is replaced with silver-plated nylon (SPN), whose conductivity is 1584.98 S / m. When preparing the MPTS self-assembled anti-corrosion film, the dried SPNE is placed in a 0.5 mol / L mixed solvent of MPTS and acetone and the magnetic stirring time is 60 min. The constant voltage deposition parameters for preparing the Ag / AgCl polarized / non-polarized composite structure layer are chlorination voltage of 1.5 V and chlorination time of 12 s, which is recorded as silver / silver chloride / trimercaptopropyltrimethoxysilane / silver-plated nylon fabric electrode (Ag / AgCl / MPTS / SPNE).

[0050] Comparative Example 3

[0051] The difference from Example 1 is that only SSYE is included, and the MPTS self-assembled anti-corrosion layer and the Ag / AgCl polarized / non-polarized composite structure layer are not included.

[0052] Comparative Example 4

[0053] The difference from Comparative Example 1 is that only SPCWE is included, and the MPTS self-assembled anti-corrosion layer and the Ag / AgCl polarized / non-polarized composite structure layer are not included.

[0054] Comparative Example 5

[0055] The difference from Comparative Example 2 is that only the SPNE fabric electrode is included, and the MPTS self-assembled anti-corrosion layer and the Ag / AgCl polarized / non-polarized composite structure layer are not included.

[0056] Comparative Example 6

[0057] It is a commercially available disposable medical wet electrode sheet.

[0058] Test Example 1

[0059] The open circuit potential, impedance spectrum (frequency 0.01-100000Hz) and Tafel polarization curve (measurement potential -0.6V-0.6V, scanning speed 10mV / s) of the sample were tested using an electrochemical workstation. The corrosion inhibition rate of the sample was calculated by the corrosion inhibition rate, and the calculation formula of the corrosion inhibition rate is as follows:

[0060]

[0061] In the formula, J 0，corr With J corr Represent the corrosion current of the electrode without MPTS treatment and after MPTS treatment for different time periods.

[0062] The optimal anti-corrosion treatment parameters were determined. When SSYE, SPCWE and SPNE were placed in a 0.5 mol / L mixed solvent of MPTS and acetone and magnetically stirred for 45 min, 45 min and 60 min respectively, their electrochemical impedance was the lowest and the corrosion inhibition rate was the highest (99.94%, 81.48% and 89.7% respectively).

[0063] Determination of optimal chlorination treatment parameters:

[0064] When the chlorination voltage of constant voltage deposition is 1.5V and the chlorination time is 12s, the impedance and phase angle of Ag / AgCl / MPTS / SPNE are the lowest.

[0065] When the chlorination voltage of constant voltage deposition is 2.5V and the chlorination time is 4s, the impedance and phase angle of Ag / AgCl / MPTS / SPCWE are the lowest.

[0066] When the chlorination voltage of constant voltage deposition is 1.5V and the chlorination time is 120s, the impedance and phase angle of Ag / AgCl / MPTS / SSYE are the lowest.

[0067] In order to evaluate the electrochemical properties of the fabric electrodes, an electrochemical workstation was used to measure the electrochemical impedance spectra and equivalent circuit models of SPNE, SPCWE, SSYE, Ag / AgCl / MPTS / SPNE, Ag / AgCl / MPTS / SPCWE, and Ag / AgCl / MPTS / SSYE at the electrode-electrolyte interface and electrode-skin interface in electrolyte (0.9% NaCl solution) and on human forearm skin under the optimal antiseptic treatment and optimal chlorination treatment parameters, respectively. Figure 3 As shown. ECG signals mainly exist in the low-frequency region (0.1-100Hz), therefore, the electrochemical impedance spectrum of the electrode in the frequency range of 0.1Hz-100kHz was measured. At the electrolyte interface of 0.9% NaCl solution, a three-electrode system including a working electrode, a counter electrode and a reference electrode was used for measurement. Among them, the working electrode is the sample electrode to be tested, the counter electrode is a platinum electrode, and the reference electrode is a calomel electrode. On the surface of human skin, a three-electrode system is also used, in which the working electrode is the electrode to be tested, the counter electrode and the reference electrode are commercial wet electrodes, and the center distance of each electrode is 5cm. The inner side of the human forearm was selected as the electrode fitting point, and the test environment was a constant humidity room temperature environment.

[0068] See also Figure 3 ad in the electrolyte interface, in the high-frequency region, the impedance of all electrodes basically remains unchanged. In the low-frequency region, except that the impedance of Ag / AgCl / MPTS / SPNE is significantly improved compared with SPNE, the resistance of Ag / AgCl / MPTS / SPCWE and Ag / AgCl / MPTS / SSYE are significantly reduced compared with before treatment. At 0.1Hz, the impedances of SPNE and Ag / AgCl / MPTS / SPNE are 57.6Ω and 5000Ω, respectively, with an impedance increase rate of 8580.6%; the impedances of SPCWE and Ag / AgCl / MPTS / SPCWE are 923Ω and 49.5Ω, respectively, with an impedance decrease rate of 94.64%; the impedances of SSYE and Ag / AgCl / MPTS / SSYE are 1210Ω and 14.7Ω, respectively, with an impedance decrease rate of 98.79%. Figure 3 As shown in b, after chlorination treatment, the phase angles of SPNE, SPCWE and SSYE all decreased. Compared with SPNE, SPCWE and SSYE, the phase angle reduction rates of Ag / AgCl / MPTS / SPNE, Ag / AgCl / MPTS / SPCWE and Ag / AgCl / MPTS / SSYE at 0.1Hz were 55.13%, 26.59% and 76.06%, respectively. At the electrode-electrolyte interface, except for SPCWE, the Nyquist plots of all electrodes are approximately a straight line, which is a typical semi-wireless diffusion process. For details, see Figure 3c. The impedance and phase values ​​of Ag / AgCl / MPTS / SSYE are the lowest, and the electrochemical performance is the best, followed by Ag / AgCl / MPTS / SPCWE. The equivalent circuit models between SSYE and Ag / AgCl / MPTS / SSYE and the electrolyte are the parallel behavior of the electrode resistance (Rs) in series and the interface capacitance and resistance, where the interface resistance is the resistance encountered when the charge is transferred at the electrode interface during the electrochemical reaction (Rp) and the Warburg impedance generated by the diffusion process (W 1 ) are connected in series. Compared with SSYE, the resistance of Ag / AgCl / MPTS / SSYE is slightly increased, but in the electrochemical reaction, the resistance encountered when the charge is transferred at the interface and the impedance generated by the diffusion process in the low-frequency region are reduced by thousands of times, indicating that the anti-corrosion treatment is helpful to improve the quality of bioelectricity collection.

[0069] See also Figure 3 In the middle ef, at the skin interface, in the low frequency region, the impedance and phase angle of Ag / AgCl / MPTS / SPNE, Ag / AgCl / MPTS / SPCWE, and Ag / AgCl / MPTS / SSYE were lower than those of SPNE, SPCWE, and SSYE before antiseptic treatment. At 0.1Hz, the impedance reduction rates of Ag / AgCl / MPTS / SPNE, Ag / AgCl / MPTS / SPCWE, and Ag / AgCl / MPTS / SSYE were 44.55%, 76.88%, and 66.19%, respectively, and the phase angle reduction rates were 52.38%, 53.64%, and 79.22%, respectively, compared with SPNE, SPCWE, and SSYE. Figure 3 The figure in g shows that at the electrode-skin interface, the Nyquist plots of SPNE, SPCWE, SSYEE, Ag / AgCl / MPTS / SPNE, Ag / AgCl / MPTS / SPCWE, and Ag / AgCl / MPTS / SSYE are semicircular, which is a typical charge transfer process. The distance from the intersection of the semicircle and the real axis to the origin represents the migration impedance of the electrode on the skin surface. The smaller this distance, the smaller the impedance. The diameters of Ag / AgCl / MPTS / SPNE, Ag / AgCl / MPTS / SPCWE, and Ag / AgCl / MPTS / SSYE are significantly smaller than those of SPNE, SPCWE, and SSYE, which means that after MPTS antiseptic treatment, the impedance caused by charge transfer of the fabric electrode at the skin and electrolysis interface is reduced. Among them, the impedance value and phase value of Ag / AgCl / MPTS / SSYE are the lowest, which are 215KΩ and 3.2deg respectively at 0.1Hz, and the electrochemical performance is the best. Figure 3 Figure 3 shows that at the electrode-skin interface, the equivalent circuit model of SSYE and Ag / AgCl / MPTS / SSYE is the resistance of the electrode itself (R s) The parallel behavior of the series interface capacitance and the resistance encountered when the charge is transferred at the electrode interface. Although the resistance of Ag / AgCl / MPTS / SSYE itself increased by 1.32 times compared with SSYE fabric electrode, the resistance encountered when the charge is transferred at the interface during the electrochemical reaction was reduced by 3.10 times. The anti-corrosion treated Ag / AgCl / MPTS / SSYE can provide a more efficient and sensitive electrochemical response, which helps to improve the accuracy and reliability of the physiological electrical signal acquisition process.

[0070] Test Example 2

[0071] The fabric electrodes prepared in Example 1 and Comparative Examples 1 to 5 were immersed in artificial sweat with a pH of 5.5 and Na 2 S solution for two months in order to compare the corrosion resistance of different fabric electrodes before and after corrosion protection and chlorination.

[0072] See also Figure 4 In figure a, the resistance of SPNE reached 60.375 MΩ after being placed in simulated sweat for 15 days, and it was no longer conductive on the 20th day. However, the resistance of Ag / AgCl / MPTS / SPNE disappeared only after being immersed in sweat for 45 days, indicating that the antiseptic treatment improved the antiseptic performance of SPNE. Figure 4 Figure b shows the resistance change of SPCWE and Ag / AgCl / MPTS / SPCWE after being corroded by simulated sweat. After 20 days of corrosion, the resistance is 5.54MΩ and 5.11MΩ. Figure 4 As can be seen in figure c, after being placed in sweat for 2 months, the resistance of Ag / AgCl / MPTS / SSYE is 0.3Ω, which is lower than the 0.56Ω of SSYE. Figure 4 In df, it is shown in Na 2 In S solution, as the immersion time increases, the resistance of the electrode without anti-corrosion treatment increases linearly. After anti-corrosion treatment, the resistance change rate of the electrode is linear. After 1920 minutes, the resistance change rate of Ag / AgCl / MPTS / SPNE is 72.67 times lower than that of SPNE. For details, see Figure 4 The resistance change of Ag / AgCl / MPTS / SPCWE is 14.68 times lower than that of SPCWE. Figure 4 The resistance change of Ag / AgCl / MPTS / SSYE is 10.09 times lower than that of SSYE. Figure 4 Middle f.

[0073] In sweat, Na 2The corrosion resistance experiments in S solution showed that after MPTS anti-corrosion and chlorination treatment, the corrosion resistance of SPNE, SPCWE and SSYE were significantly improved, and the corrosion resistance of Ag / AgCl / MPTS / SSYE was the best.

[0074] Test Example 3

[0075] The physiological signal recording and analysis system produced by BIOPAC of the United States was used to collect the physiological electrical signals of the fabric electrodes prepared in Example 1, Comparative Examples 1-5, and the wet electrode of Comparative Example 6. The resistance signals of the fabric electrodes prepared in Example 1, Comparative Examples 1-5, and the wet electrode of Comparative Example 6 were collected using a U3402A multimeter produced by Agilent Technologies Inc.

[0076] The fabric electrodes prepared in Example 1, Comparative Examples 1-5 and the wet electrode prepared in Comparative Example 6 were respectively integrated 5 cm below the left and right BP points of the chest circumference line of the sports vest as working electrodes and counter electrodes, respectively. A ground electrode was integrated at the point where the left BP point intersected with the waistline for measuring electrocardiogram signals. For details, see Figure 5 In a.

[0077] The fabric electrodes prepared in Example 1, Comparative Examples 1-5 and the wet electrode prepared in Comparative Example 6 were respectively integrated in the middle of the biceps brachii muscle of the upper arm of the protective sleeve as working electrodes, and the counter electrode was placed 5 cm away from the working electrode along the muscle fiber direction. The ground electrode was placed in the center of the sleeve wrist for measuring electromyographic signals. For details, see Figure 5 a and b. The electrodes are integrated into the sports compression stockings and are respectively aimed at the gastrocnemius muscles. Figure 5 In Figure c, neuromuscular electrical stimulation is used to achieve the purpose of recovery from sports fatigue. A self-made single-test device is used to evaluate the actual current, voltage and pulse signal between electrodes during electrical stimulation, and the sensor performance of the electrode is determined by evaluating the deviation between the actual signal and the prescribed signal of different electrodes.

[0078] Baseline drift, P wave waveform, T wave waveform and signal-to-noise ratio (SNR) are used as the basis for evaluating the quality of ECG and EMG signals.

[0079] The signal-to-noise ratio is the ratio of the power of the effective component in the signal to the power of the noise component. The higher the signal-to-noise ratio, the better the quality of the collected ECG signal. The signal-to-noise ratio calculation formula is:

[0080]

[0081] Where V s Represents the effective signal voltage in mV, V n Represents the noise voltage in mV.

[0082] Reference Figure 6 and Figure 7 In figure a, wet electrode, SPNE, Ag / AgCl / MPTS / SPNE, SPCWE, Ag / AgCl / MPTS / SPCWE, SSYE, Ag / AgCl / MPTS / SSYE can all acquire stable ECG signals without baseline drift, and the P-QRS-T waves are clearly visible. Their signal amplitudes are 0.6198mV, 0.3995mV, 0.2940mV, 0.5592mV, 0.5189mV, 0.6599mV and 0.5524mV, respectively. Their noise amplitudes are 0.0455mV, 0.0458mV, 0.0894mV, 0.1145mV, 0.1067mV, 0.1051mV and 0.0419mV, respectively. Figure 7 As can be seen in a, the P wave and T wave of Ag / AgCl / MPTS / SSYE have higher fluctuation amplitudes (0.0294mV and 0.0806mV respectively), smaller fluctuation range, the highest signal-to-noise ratio (22.47dB), and the collected ECG signal has the best quality.

[0083] Reference Figure 7 In middle b, after being placed in the air for 2 months, the wet electrode can no longer measure the ECG signal, the SPNE is obviously oxidized, the SPNE has a serious baseline drift, and the ECG signal of Ag / AgCl / MPTS / SPNE is severely distorted. The P-QRS-T waves can be distinguished by both SPCWE and SSYE, but the SPCWE baseline has noise, and the SSYE has a slight baseline drift. Compared with SPCWE and SSYE, the stability of the P wave and T wave of Ag / AgCl / MPTS / SPCWE and Ag / AgCl / MPTS / SSYE is improved. Although the signal-to-noise ratio of Ag / AgCl / MPTS / SSYE is reduced by 6.4% compared with before oxidation, its signal-to-noise ratio is still the highest compared with the other five electrodes, and the ECG signal is still the best.

[0084] Reference Figure 7In middle c, after 2 months of corrosion in sweat, wet electrode, SPNE, Ag / AgCl / MPTS / SPNE, SPCWE and Ag / AgCl / MPTS / SPCWE could no longer collect ECG signals. The P wave of SSYE showed noise and poor discernibility, while the P-QRS-T wave collected by Ag / AgCl / MPTS / SSYE was still clearly visible. The P wave amplitudes of SSYE and Ag / AgCl / MPTS / SSYE were 0.0089mV and 0.0337mV, respectively, and the T wave amplitudes were 0.0689mV and 0.0599mV, respectively, and the signal-to-noise ratios were 7.2833dB and 14.4074dB, respectively. This indicates that MPTS antiseptic and chlorination treatment can significantly improve the corrosion resistance of SSYE, and the ECG quality of Ag / AgCl / MPTS / SSYE is still good even after immersion in sweat for 2 months.

[0085] Reference Figure 8 In figure a, wet electrode, SPNE, Ag / AgCl / MPTS / SPNE, SPCWE, Ag / AgCl / MPTS / SPCWE, SSYE, and Ag / AgCl / MPTS / SSYE can all collect stable EMG signals. Figure 8 Figure d is a schematic diagram of effective signal and noise signal. Figure 8 In the figure, their signal-to-noise ratios are 19.13dB, 15.69dB, 15.84dB, 14.1dB, 15.38dB, 15.11dBV and 17.13dB respectively. Figure 8 Medium b and Figure 8 In figure f, after being placed in the air for 2 months, SPNE, Ag / AgCl / MPTS / SPNE, SPCWE, Ag / AgCl / MPTS / SPCWE, SSYE, and Ag / AgCl / MPTS / SSYE can still collect good EMG signals. The wet electrode can no longer collect EMG signals. The EMG signal-to-noise ratio collected by Ag / AgCl / MPTS / SPCWE and Ag / AgCl / MPTS / SSYE is improved by 39.05% and 46.82% compared with SPCWE and SSYE, respectively. Figure 8 In middle c, after 2 months of corrosion in sweat, only SSYE and Ag / AgCl / MPTS / SSYE can still collect EMG signals, with signal-to-noise ratios of 15.19 dB and 20.58 dB, respectively.

[0086] Reference Fig. 9 A and Fig. 9 In b, muscle stimulation was measured by a homemade single-point device, and the deviation between the actual current and pulse voltage between different electrodes and the prescribed signal was used to evaluate the electrical stimulation sensing performance of different electrodes. Fig. 9 Medium D and Fig. 9 In g, the actual stimulation voltage and current generated by the wet electrode before corrosion are significantly higher than those of SPNE, Ag / AgCl / MPTS / SPNE, SPCWE, Ag / AgCl / MPTS / SPCWE, SSYE, and Ag / AgCl / MPTS / SSYE. After oxidizing in air for 2 months, Fig. 9 Zhongehe Fig. 9 In the middle h, the stimulation signals of SPNE, Ag / AgCl / MPTS / SPNE, SPCWE, Ag / AgCl / MPTS / SPCWE, SSYE, and Ag / AgCl / MPTS / SSYE were all reduced. Fig. 9 Taking c) as an example, the stimulation signals generated by SPNE, Ag / AgCl / MPTS / SPNE, SPCWE, Ag / AgCl / MPTS / SPCWE, SSYE and Ag / AgCl / MPTS / SSYE decreased by 18.05%, 19.97%, 22.26%, 23.95%, 22.73% and 23.70% respectively compared with those before corrosion. Fig. 9 Medium f and Fig. 9 In Figure 1, after 2 months of corrosion in sweat, only SSYE and Ag / AgCl / MPTS / SSYE can still detect stimulation signals. Compared with oxidation in air, the stimulation signals of SSYE and Ag / AgCl / MPTS / SSYE only decreased by 1.7% and 0.8% (taking the frequency at Prescription 3-1Hz as an example, see Fig. 9 (c).

[0087] The above results show that SPNE, Ag / AgCl / MPTS / SPNE, SPCWE, Ag / AgCl / MPTS / SPCWE, SSYE, and Ag / AgCl / MPTS / SSYE have less information loss than wet electrodes and are more suitable as electrical stimulation electrodes. In sweat, SSYE has the best corrosion resistance, and Ag / AgCl / MPTS / SSYE has better corrosion resistance than SSYE at the frequency of Prescription 3-1Hz (see Fig. 9 Taking c) as an example, the stimulation voltage increased by 20mV and the stimulation current increased by 0.04mA.

[0088] In summary, the present invention prepares Ag / AgCl / MPTS / SSYE by chemical modification and constant voltage deposition. Ag / AgCl / MPTS / SSYE has excellent corrosion resistance, comfort and electrical properties. MPTS anti-corrosion treatment effectively improves the corrosion resistance of ultrafine silver wire, and the corrosion inhibition rate reaches 99.94%. After two months of corrosion in simulated sweat, the resistance of Ag / AgCl / MPTS / SSYE only increased by 0.02Ω, and the signal-to-noise ratios of electrocardiogram and electromyography were 14.4074dB and 20.58dB, respectively. The resistance change rate of Ag / AgCl / MPTS / SSYE after washing 100 times and wearing 9000 times was 0.1% and 0.3%, respectively. Ag / AgCl / MPTS / SSYE can be integrated into smart clothing and wearable devices as a bioelectric collection electrode, and has broad application potential in the fields of health care, remote patient monitoring and fitness guidance.

[0089] The above is only a preferred embodiment of the present invention. It should be pointed out that, for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A highly corrosion-resistant ultrafine silver wire fabric electrode, characterized in that: The highly corrosion-resistant ultrafine silver wire fabric electrode comprises an SSYE conductive layer, an MPTS self-assembled anti-corrosion layer and an Ag / AgCl polarized / non-polarized composite structure layer. The SSYE conductive layer is obtained by sewing an ultrafine silver wire bundle onto a substrate fabric. After sewing, the ultrafine silver wire bundle forms a continuous SSYE conductive layer on the front and back sides. The surface of the SSYE conductive layer is uniformly coated with the MPTS self-assembled anti-corrosion layer. The surface of the MPTS self-assembled anti-corrosion layer is uniformly coated with the Ag / AgCl polarized / non-polarized composite structure layer.

2. The highly corrosion-resistant ultrafine silver wire fabric electrode according to claim 1, characterized in that: The highly corrosion-resistant ultrafine silver wire fabric electrode is circular in shape, with a diameter of 10 to 30 mm and a thickness of 2 to 3 mm.

3. The highly corrosion-resistant ultrafine silver wire fabric electrode according to claim 1, characterized in that: The substrate fabric is formed by hot-pressing high-density plain woven cotton fabric and adhesive lining. Preferably, the warp and weft densities of the high-density plain woven cotton fabric are both 500-700 / 10cm, and the adhesive lining is a polyester-cotton blended fabric.

4. The highly corrosion-resistant ultrafine silver wire fabric electrode according to claim 1, characterized in that: The preparation method of the SSYE conductive layer is: twisting ultrafine silver threads into ultrafine silver thread bundles, and then sewing the ultrafine silver thread bundles onto a substrate fabric through an embroidery process to obtain the SSYE conductive layer.

5. The highly corrosion-resistant ultrafine silver wire fabric electrode according to claim 4, characterized in that: The ultrafine silver wire bundle is formed by twisting 16 to 28 ultrafine silver wires with a diameter of 0.030 to 0.090 mm. The diameter of the ultrafine silver wire bundle is 0.2 to 0.4 mm, and the electrical conductivity is 81836 to 111835.97 S / m.

6. The highly corrosion-resistant ultrafine silver wire fabric electrode according to claim 4, characterized in that: The embroidery technique is the Cantonese embroidery technique, the embroidery stitches are spiral, the needle length is 1 to 3 mm, and the needle distance is 0.4 to 0.8 mm.

7. A method for preparing the highly corrosion-resistant ultrafine silver wire fabric electrode according to claim 1, characterized in that: The following steps are involved: Step 1, preparation of SSYE conductive layer: sew twisted ultrafine silver thread bundles on the substrate fabric through embroidery process, so that the ultrafine silver thread bundles are continuously distributed on the front and back sides of the substrate fabric to obtain SSYE conductive layer. After the embroidery is completed, the SSYE conductive layer is hot pressed and cleaned, and impurities on the surface of the SSYE conductive layer are removed by ultrasonic wave, and then dried; Step 2, preparation of MPTS self-assembled anticorrosion layer: placing the dried SSYE conductive layer obtained in step 1 in a 0.1-1 mol / L MPTS and acetone mixed solvent and stirring, then placing it in deionized water, taking it out, and drying it to obtain a trimercaptopropyltrimethoxysilane / ultrafine silver wire fabric electrode MPTS / SSYE; Step 3, preparation of Ag / AgCl polarized / non-polarized composite structure layer: using the trimercaptopropyltrimethoxysilane / ultrafine silver wire fabric electrode MPTS / SSYE obtained in step 2 as a working electrode, the Ag / AgCl electrode as a reference electrode, and the platinum sheet electrode as a counter electrode, in an electrolyte solution, constant voltage deposition is performed on MPTS / SSYE by a constant voltage deposition method to form an Ag / AgCl polarized / non-polarized composite structure layer, and silver / silver chloride / trimercaptopropyltrimethoxysilane / ultrafine silver wire fabric electrode Ag / AgCl / MPTS / SSYE, i.e., a highly corrosion-resistant ultrafine silver wire fabric electrode.

8. The method for preparing the highly corrosion-resistant ultrafine silver wire fabric electrode according to claim 7, characterized in that: The hot pressing temperature in step 1 is 120-130° C., and the hot pressing time is 15-30 seconds.

9. The method for preparing a highly corrosion-resistant ultrafine silver wire fabric electrode according to claim 7, characterized in that: The electrolyte in step 3 is a sodium chloride solution with a mass fraction of 0.7-1.0%, and the constant voltage deposition parameters are a chlorination voltage of 0.5-2.5V and a chlorination time of 30-150s.

10. Use of the highly corrosion-resistant ultrafine silver wire fabric electrode according to claim 1 in physiological electrical signal monitoring or electrical stimulation therapy.

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