Nanocarbon-loaded silver chloride composite slurry and preparation method and application thereof

Abstract

The invention relates to the technical field of flexible electrodes, and provides nano-carbon-loaded silver chloride composite slurry as well as a preparation method and application thereof. The nanocarbon-loaded silver chloride composite paste provided by the invention comprises 10 to 25% of AgCl / CNTs powder, 30 to 50% of silver powder and 25 to 60% of an organic resin carrier. The silver chloride in the composite slurry provided by the invention is good in dispersion uniformity and stability, the problems of silver chloride agglomeration and decomposition can be effectively avoided, and the conductivity and chemical stability of the composite slurry are improved; the composite slurry provided by the invention has the advantages of low sheet resistance, firm adhesion, excellent electrochemical stability, strong anti-interference capability, good biocompatibility and the like, also has good printability, is suitable for a silk-screen printing process, can be used for producing electrodes with specific shapes according to different use environments, is easy for mass production, and has a wide application prospect.

Description

Technical Field

[0001] This invention relates to the field of flexible electrode technology, and in particular to a nano-carbon-supported silver chloride composite slurry, its preparation method, and its application. Background Technology

[0002] Silver-silver chloride paste possesses excellent conductivity and stability. Reference electrodes prepared using it exhibit high sensitivity and fast signal response, and are widely used in fields such as glucose, deoxyribonucleic acid (DNA), and protein detection.

[0003] With the development of the healthcare field, the flexible biosensor industry is experiencing rapid expansion worldwide. Flexible biosensors, with their bendable and stretchable properties, can be closely fitted to the skin or implanted within the body, demonstrating significant advantages in real-time monitoring of physiological health information such as blood glucose, heart rate, and biomarker concentrations. As the core component of flexible biosensors, the performance of the electrodes directly determines whether the sensor can achieve continuous and accurate monitoring. This places higher demands on the silver-silver chloride paste used to prepare the electrodes: to match the portability of flexible biosensors, the paste must possess good printability and low sheet resistance to ensure efficient transmission of weak physiological signals and avoid signal attenuation; to meet the sensor's excellent stretchability and long-term wear requirements, the paste must have strong adhesion properties after curing; from the perspective of detection accuracy and stability, the paste must possess excellent electrochemical stability, with no significant electrode impedance drift during long-term use, and strong anti-interference capabilities to effectively resist interference from skin secretions and external electromagnetic environments, ensuring data accuracy.

[0004] Traditional methods for preparing silver-silver chloride paste primarily rely on physical mixing. This method involves directly adding silver powder and silver chloride powder to an organic resin carrier, then using high-speed stirring or ball milling to uniformly disperse the silver and silver chloride powders within the carrier, forming a printable or coatable paste. However, this method results in poor silver chloride dispersion, insufficient electrochemical stability, and easily fluctuating electrode impedance over time, potentially introducing significant noise and errors in high-precision detection. Summary of the Invention

[0005] In view of this, the present invention provides a nano-carbon-supported silver chloride composite paste, its preparation method, and its application. The nano-carbon-supported silver chloride composite paste provided by the present invention exhibits uniform silver chloride dispersion and good stability, effectively improving the conductivity and chemical stability of the composite paste. It also possesses advantages such as low sheet resistance, strong adhesion, strong anti-interference ability, and good printability.

[0006] To achieve the above-mentioned objectives, the present invention provides the following technical solution:

[0007] A nano-carbon-supported silver chloride composite slurry comprises the following components by mass fraction: 10-25% AgCl / CNTs powder, 30-50% silver powder, and 25-60% organic resin carrier; wherein the AgCl / CNTs powder comprises carbon nanotubes and silver chloride particles loaded on the carbon nanotubes.

[0008] Preferably, the method for preparing the AgCl / CNTs powder includes:

[0009] Functionalized carbon nanotubes are obtained by acidifying carbon nanotubes.

[0010] The functionalized carbon nanotubes and surfactant solution are mixed to obtain a functionalized carbon nanotube suspension.

[0011] The functionalized carbon nanotube suspension and silver nitrate solution were mixed to obtain a mixed solution;

[0012] The reducing agent and the mixture are mixed to carry out a reduction reaction, thereby obtaining carbon nanotubes loaded with silver nanoparticles.

[0013] The carbon nanotubes loaded with silver nanoparticles were immersed in a chlorine-containing solution for chlorination treatment to obtain AgCl / CNTs powder.

[0014] Preferably, the acid used in the acidification treatment is concentrated nitric acid; the ratio of carbon nanotubes to concentrated nitric acid is 1g:50-100mL; the acidification temperature is 50-100℃, and the time is 5-10h.

[0015] The surfactant in the surfactant solution includes one or both of sodium dodecylbenzenesulfonate and sodium dodecyl sulfate; the mass ratio of the functionalized carbon nanotubes to the surfactant is 7.5–9:1–2.5.

[0016] Preferably, the concentration of the silver nitrate solution is 0.5–2 mol / L, and the volume ratio of the silver nitrate solution to the functionalized carbon nanotube suspension is 1:1–2.5.

[0017] The reducing agent is one or more of formaldehyde, hydrazine hydrate, and ascorbic acid; the molar ratio of silver nitrate to reducing agent in the silver nitrate solution is 1:1.5 to 10.

[0018] Preferably, the chlorine-containing solution is a silver salt solution containing chloride, and the chloride is NaCl and / or HCl; the chlorination treatment is carried out at a temperature of 20–50°C for a time of 0.5–2 hours.

[0019] Preferably, the raw material preparation of the organic resin carrier, by mass fraction, comprises: 55-75% organic solvent, 25-45% resin, and 0-5% curing agent;

[0020] The resin includes one or more of polyvinylidene chloride, chloroprene rubber, chloroacetic acid resin, chloroether resin, modified phenolic resin, modified epoxy resin, modified cyanate ester resin, modified acrylic resin, and modified furfuryl alcohol resin; the curing agent includes one or more of imidazole, aliphatic amine, and isocyanate.

[0021] The organic solvent includes one or more of butyl acetate, dimethyl succinate, dimethyl glutarate, dimethyl adipate, 2-ethylhexyl formate, ethanol, ethyl acetate, diethylene glycol ethyl ether acetate, cyclohexanone, ethylene glycol ethyl ether acetate, and ethylene glycol butyl ether acetate.

[0022] Preferably, the method for preparing the organic resin carrier includes: dissolving the resin in an organic solvent to obtain a resin solution; mixing the resin solution and a curing agent to obtain an organic resin carrier; when the amount of curing agent is 0, the step of mixing the resin solution and the curing agent is omitted.

[0023] This invention also provides a method for preparing the nano-carbon-supported silver chloride composite slurry described above, comprising the following steps:

[0024] AgCl / CNTs powder was mixed with silver powder to obtain a mixed powder;

[0025] The mixed powder was ground and dispersed with an organic resin carrier to obtain a nano-carbon-supported silver chloride composite slurry.

[0026] The present invention also provides the application of the nano-carbon-supported silver chloride composite slurry described in the above-described scheme or the nano-carbon-supported silver chloride composite slurry prepared by the preparation method described in the above-described scheme in electrodes.

[0027] Preferably, the electrode includes a biosensor electrode, an electrochemical reference electrode, or an electrocardiogram electrode;

[0028] The method of application includes: screen printing the nano-carbon-supported silver chloride composite paste and then curing it to obtain an electrode; the curing temperature is 80-150℃ and the time is 5-30 min.

[0029] This invention provides a nano-carbon-supported silver chloride composite slurry, comprising the following components by mass fraction: 10-25% AgCl / CNTs powder, 30-50% silver powder, and 25-60% organic resin carrier; wherein the AgCl / CNTs powder comprises carbon nanotubes and silver chloride particles loaded on the carbon nanotubes. This invention uses carbon nanotubes as a carrier, loads silver chloride particles onto their surface, and mixes them with organic resin and silver powder to form a composite slurry. This effectively improves the dispersion uniformity and stability of silver chloride, avoids silver chloride agglomeration and decomposition problems, and enhances the conductivity and chemical stability of the composite slurry. Simultaneously, the composite slurry provided by this invention also has advantages such as low sheet resistance, strong adhesion, excellent electrochemical stability, strong anti-interference ability, and good biocompatibility. The composite slurry provided by this invention has good printability and is suitable for screen printing processes. It can be used to produce flexible bioelectrodes, reference electrodes, and environmental testing electrodes, enabling the production of electrodes with specific shapes for different application environments. It is low-cost and easy to mass-produce. Electrode preparation via screen printing avoids the high-voltage sheeting processes required in existing silver / silver chloride bioelectrode preparation, overcoming the cumbersome nature of traditional methods. While ensuring the required electrochemical performance of the electrode, it greatly improves preparation efficiency and is suitable for industrial production.

[0030] The results of the examples show that the silver / silver chloride bioelectrode prepared using the nano-carbon-supported silver chloride composite slurry of the present invention has a stable potential. This electrode can be used for in vitro bioelectrical signal examination and recording, and can obtain reliable bioelectrical signals. The sheet resistance of the silver / silver chloride bioelectrode is <0.3Ω / □, and it shows excellent adhesion under the 3M tape adhesion test, with 100% no detachment. At the same time, it can maintain excellent self-noise performance in the low frequency band and has good electrical signal testing capabilities. The potential stability test shows that the electrode has good potential stability, and its electrode potential can be quickly stabilized in a short time. Moreover, the change in electrode potential per hour does not exceed 1mV over a long period of time, which fully meets the requirements for conventional bioelectrical signal measurement and can be widely used in the measurement of in vitro bioelectrical signals. Attached Figure Description

[0031] Figure 1 This is a transmission electron microscope image of the AgCl / CNTs powder prepared in Example 1 of the present invention;

[0032] Figure 2 This is a transmission electron microscope image of the AgCl / CNTs powder prepared in Example 2 of the present invention. Detailed Implementation

[0033] This invention provides a nano-carbon-supported silver chloride composite slurry, comprising the following components by mass fraction: 10-25% AgCl / CNTs powder, 30-50% silver powder, and 25-60% organic resin carrier; wherein the AgCl / CNTs powder comprises carbon nanotubes and silver chloride particles loaded on the carbon nanotubes.

[0034] The nano-carbon-supported silver chloride composite slurry provided by this invention comprises 20-50% AgCl / CNTs powder, specifically 15%, 20%, or 25%; the AgCl / CNTs powder comprises carbon nanotubes (CNTs) and silver chloride particles loaded on the carbon nanotubes; the mass fraction of silver chloride nanoparticles in the AgCl / CNTs powder is preferably 20-60%; the specific surface area of ​​the AgCl / CNTs powder is preferably 150-200 m². 2 / g.

[0035] In this invention, the preferred method for preparing the AgCl / CNTs powder includes:

[0036] Functionalized carbon nanotubes are obtained by acidifying carbon nanotubes.

[0037] The functionalized carbon nanotubes and surfactant solution are mixed to obtain a functionalized carbon nanotube suspension.

[0038] The functionalized carbon nanotube suspension and silver nitrate solution were mixed to obtain a mixed solution;

[0039] The reducing agent and the mixture are mixed to carry out a reduction reaction, thereby obtaining carbon nanotubes loaded with silver nanoparticles.

[0040] The carbon nanotubes loaded with silver nanoparticles were immersed in a chlorine-containing solution for chlorination treatment to obtain AgCl / CNTs powder.

[0041] This invention involves acidifying carbon nanotubes to obtain functionalized carbon nanotubes. In this invention, the acid used for acidification is preferably concentrated nitric acid, specifically nitric acid with a mass fraction of 68%; the preferred ratio of carbon nanotubes to concentrated nitric acid is 1g:50-100mL, specifically 1g:75mL or 1g:100mL; the preferred acidification temperature is 50-100℃, and the preferred time is 5-10 hours; the acidification is preferably carried out under stirring conditions; after acidification, the resulting acidified solution is preferably filtered through a filter membrane and then washed to obtain functionalized carbon nanotubes. This invention improves the wettability of CNTs in water through acidification and provides more nucleation sites for subsequent silver nucleation.

[0042] After obtaining functionalized carbon nanotubes, this invention mixes the functionalized carbon nanotubes with a surfactant solution to obtain a carbon nanotube suspension. In this invention, the surfactant in the surfactant solution preferably includes one or both of sodium dodecylbenzenesulfonate and sodium dodecyl sulfate; the concentration of the surfactant solution is preferably 0.1–1 g / L, specifically 0.1 g / L, 0.5 g / L, or 1 g / L; the solvent of the surfactant solution is water; the mass ratio of the functionalized carbon nanotubes to the surfactant is preferably 7.5–9:1–2.5, specifically 7.5:2.5 or 8:2; the mixing method of the functionalized carbon nanotubes and the surfactant solution is preferably ultrasonic dispersion, the ultrasonic dispersion time is preferably 0.5–2 h, and the ultrasonic dispersion is preferably carried out under ice bath conditions. This invention, by adding a surfactant, can improve the dispersibility of functionalized carbon nanotubes and prevent their aggregation.

[0043] After obtaining the functionalized carbon nanotube suspension, the present invention mixes the functionalized carbon nanotube suspension with a silver nitrate solution to obtain a mixed solution. In the present invention, the concentration of the silver nitrate solution is preferably 0.5-2 mol / L, specifically 0.5 mol / L, 1 mol / L, or 2 mol / L; the volume ratio of the silver nitrate solution to the functionalized carbon nanotube suspension is preferably 1:1-2.5, specifically 1:1, 1:2, or 1:2.5; the mixing of the functionalized carbon nanotube suspension and the silver nitrate solution is preferably carried out under magnetic stirring conditions, and the magnetic stirring time is preferably 5-10 h, specifically 6 h.

[0044] After obtaining the mixed solution, the present invention mixes the reducing agent with the mixed solution to carry out a reduction reaction, thereby obtaining carbon nanotubes (Ag / CNTs) loaded with silver nanoparticles. In the present invention, the reducing agent is preferably one or more of formaldehyde, hydrazine hydrate, and ascorbic acid; the molar ratio of silver nitrate to reducing agent in the silver nitrate solution is preferably 1:1.5 to 10, specifically 1:1.5, 1:8, or 1:10; the temperature of the reduction reaction is preferably room temperature, and the time is preferably 0.5 to 2 hours, starting from the time the reducing agent is added completely; in a specific embodiment of the present invention, the reducing agent is preferably added to the mixed solution at a rate of 5 to 20 mL / min under room temperature and magnetic stirring conditions, and then stirring is continued at room temperature for 0.5 to 2 hours; the present invention causes silver nitrate to undergo a silver mirror reaction on the surface of functionalized carbon nanotubes through a reduction reaction, generating silver nanoparticles. After the reduction reaction is completed, the Ag / CNTs are washed with deionized water until neutral and collected by centrifugation.

[0045] After obtaining carbon nanotubes loaded with silver nanoparticles, the present invention immerses the silver-loaded carbon nanotubes in a chlorine-containing solution for chlorination treatment to obtain AgCl / CNTs powder. In the present invention, the chlorine-containing solution is preferably a silver salt solution containing chloride; the chloride is preferably NaCl and / or HCl, and the silver salt is preferably silver nitrate; in the silver salt solution containing chloride, the concentration of chloride is preferably 0.5–1.5 mol / L, specifically 0.5 mol / L, 1 mol / L, or 1.5 mol / L, and the concentration of silver salt is preferably 0.5–2 mol / L, specifically 1 mol / L; the chlorination treatment temperature is preferably 20–50℃, specifically 20℃, 35℃, or 50℃, and the chlorination treatment time is preferably 0.5–2 h, specifically 0.5 h, 1.5 h, or 2 h. After the chlorination treatment is completed, the obtained chlorinated solution is preferably allowed to stand overnight, then washed and centrifuged with ethanol to obtain AgCl / CNTs powder.

[0046] This invention prepares silver chloride particles with different particle sizes and distributions by controlling conditions such as solution concentration, reaction temperature, and reaction time, thereby obtaining AgCl / CNTs powder. Electrodes printed using nano-carbon-supported silver chloride composite paste prepared with AgCl / CNTs powder have the advantages of low sheet resistance, good adhesion, good electrode potential stability, strong anti-interference ability, and good biocompatibility.

[0047] The nano-carbon-supported silver chloride composite slurry provided by the present invention comprises 30-50% silver powder by mass fraction, specifically 30%, 40% or 50%; the average particle size of the silver powder is preferably 1-3 micrometers.

[0048] The nano-carbon-supported silver chloride composite slurry provided by this invention comprises 25-60% organic resin carrier, specifically 25%, 40%, or 55% by mass fraction. In this invention, the raw material preparation of the organic resin carrier comprises: 55-75% organic solvent, specifically 60%, 70%, or 73%; 25-45% resin, specifically 25%, 30%, or 40%; and 0-5 wt% curing agent, specifically 2%.

[0049] In this invention, the organic solvent preferably includes one or more of butyl acetate, dimethyl succinate, dimethyl glutarate, dimethyl adipate, 2-ethylhexyl formate, ethanol, ethyl acetate, diethylene glycol ethyl ether acetate, cyclohexanone, ethylene glycol ethyl ether acetate, or ethylene glycol butyl ether acetate; in a specific embodiment of this invention, the organic solvent can be a mixed solvent of dimethyl succinate, dimethyl glutarate, dimethyl adipate, and diethylene glycol butyl ether acetate, wherein the mass ratio of dimethyl succinate, dimethyl glutarate, dimethyl adipate, and diethylene glycol butyl ether acetate in the mixed solvent is preferably 1:1 to 1.5:1 to 2:1 to 3.

[0050] In this invention, the resin preferably includes one or more of polyvinylidene chloride, chloroprene rubber, chloroacetic acid resin, chloroether resin, modified phenolic resin, modified epoxy resin, modified cyanate ester resin, modified acrylic resin, and modified furfuryl alcohol resin; in this invention, the resin is preferably polyvinylidene chloride and chloroprene rubber, and the mass ratio of polyvinylidene chloride to chloroprene rubber is preferably 1:1 to 1.5.

[0051] In this invention, the curing agent preferably includes one or more of imidazole, aliphatic amine and isocyanate; the isocyanate is preferably a blocked isocyanate.

[0052] In this invention, the method for preparing the organic resin carrier preferably includes: dissolving the resin in an organic solvent to obtain a resin solution; and mixing the resin solution with a curing agent to obtain the organic resin carrier. The method for dissolving the resin in the organic solvent preferably includes: stirring the resin and the organic solvent at a temperature preferably not exceeding 70°C, and cooling to room temperature after the resin is completely dissolved; the stirring is preferably carried out in a high-speed disperser; the mixing time of the resin solution and the curing agent is preferably 40 minutes; when the amount of curing agent is 0, the step of mixing the resin solution and the curing agent is omitted, and the resulting resin solution is the organic resin carrier.

[0053] This invention also provides a method for preparing the nano-carbon-supported silver chloride composite slurry described above, comprising the following steps:

[0054] AgCl / CNTs powder was mixed with silver powder to obtain a mixed powder;

[0055] The mixed powder was ground and dispersed with an organic resin carrier to obtain a nano-carbon-supported silver chloride composite slurry.

[0056] The present invention does not have any special requirements for the mixing method of the AgCl / CNTs powder and silver powder, as long as they can be mixed evenly; the grinding and dispersion are preferably carried out in a three-roll mill, and after grinding and dispersion, the resulting mixture is preferably subjected to degassing under reduced pressure to obtain a nano-carbon-supported silver chloride composite slurry.

[0057] This invention also provides the application of the nano-carbon-supported silver chloride composite paste described in the above-described scheme or the nano-carbon-supported silver chloride composite paste prepared by the preparation method described in the above-described scheme in electrodes; the electrodes preferably include biosensor electrodes, electrochemical reference electrodes, or electrocardiogram electrodes; the application method includes: screen printing the nano-carbon-supported silver chloride composite paste and then curing it to obtain the electrode; the curing temperature is preferably 80-150℃, specifically 80℃, 100℃, or 150℃, and the curing time is preferably 5-30 min, specifically 5 min, 15 min, or 30 min.

[0058] The technical solutions of this invention will be clearly and completely described below with reference to the embodiments thereof. Obviously, the described embodiments are only a part of the embodiments of this invention, and not all of them. Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this invention.

[0059] Example 1

[0060] (1) Take 1g of CNTs, add 100mL of concentrated nitric acid, heat and stir at 100℃ for 10h, then wash the CNTs mixture with deionized water, and filter several times to obtain pure functionalized CNTs.

[0061] (2) The functionalized CNTs were added to a sodium dodecylbenzenesulfonate solution with a concentration of 0.1 g / L (the mass ratio of functionalized CNTs to surfactant was 8:2), and dispersed in an ultrasonic bath under ice bath conditions for 2 h to obtain a suspension of functionalized CNTs.

[0062] (3) The functionalized CNTs suspension was added to a 0.5 mol / L AgNO3 solution (the volume ratio of AgNO3 solution to functionalized CNTs suspension was 1:1), and stirred with a magnetic stirrer for 6 h. While stirring magnetically at room temperature, formaldehyde was added dropwise to the above system at a rate of 10 mL / min (the molar ratio of silver nitrate to formaldehyde was 1:1.5), and stirring was continued at room temperature for 0.5 h. Nano-silver was obtained by reduction on the surface of functionalized CNTs through a silver mirror reaction, thus preparing Ag / CNTs.

[0063] (4) At 20℃, Ag / CNTs were immersed in AgNO3 solution containing HCl (where the concentration of HCl was 0.5 mol / L and the concentration of AgNO3 was 1 mol / L) for chlorination treatment for 0.5 h to generate AgCl / CNTs. After standing overnight, the AgCl / CNTs powder was collected by washing with ethanol and centrifuging several times. Figure 1Transmission electron microscopy (TEM) image of the AgCl / CNTs powder prepared in Example 1; according to Figure 1 It can be seen that silver chloride particles are uniformly loaded on the surface of carbon nanotubes.

[0064] (5) Add the resin to the organic solvent, stir with a high-speed disperser, and keep the temperature below 70°C. After the resin is completely dissolved, cool to room temperature, add the curing agent, and disperse at high speed for 40 minutes to prepare an organic resin carrier. The resin has a mass fraction of 25%, the organic solvent has a mass fraction of 73%, and the curing agent has a mass fraction of 2%. The resin is polyvinylidene chloride and chloroprene rubber, with a mass ratio of 1:1. The organic solvent is a mixture of dimethyl succinate, dimethyl glutarate, dimethyl adipate, and diethylene glycol butyl ether acetate, with a mass ratio of 1:1:1:1. The curing agent is a blocked isocyanate.

[0065] (6) Mix AgCl / CNTs powder and silver powder thoroughly to obtain mixed powder. Then grind and disperse the mixed powder with organic resin carrier in a three-roll mill. Finally, degas under reduced pressure to obtain nano-carbon-supported silver chloride composite slurry, wherein the mass fraction of AgCl / CNTs powder is 15%, the mass fraction of silver powder is 30%, and the mass fraction of organic resin carrier is 55%.

[0066] The prepared nano-carbon-supported silver chloride composite paste was printed onto polypropylene by screen printing. After printing, the electrode was heat-cured at 150°C for 5 minutes to obtain a silver / silver chloride bioelectrode.

[0067] Example 2

[0068] (1) Take 1g of CNTs, add 75mL of concentrated nitric acid, heat and stir at 100℃ for 10h, then wash the CNTs mixture with deionized water, and filter several times to obtain pure functionalized CNTs.

[0069] (2) The functionalized CNTs were added to a solution of sodium dodecylbenzenesulfonate with a concentration of 0.5 g / L (the mass ratio of functionalized CNTs to surfactant was 7.5:2.5), and dispersed in an ultrasonic bath under ice bath conditions for 2 h to obtain a suspension of functionalized CNTs.

[0070] (3) The functionalized CNTs suspension was added to a 1 mol / L AgNO3 solution (the volume ratio of AgNO3 solution to functionalized CNTs suspension was 1:2), and stirred with a magnetic stirrer for 6 h. While stirring magnetically at room temperature, hydrazine hydrate was added dropwise to the above system at a rate of 5 mL / min (the molar ratio of silver nitrate to hydrazine hydrate was 1:10), and stirring was continued at room temperature for 0.5 h. Nano-silver was obtained by reduction on the surface of functionalized CNTs through a silver mirror reaction, thus preparing Ag / CNTs.

[0071] (4) Silver was chlorinated for 1.5 h by immersing Ag / CNTs in an AgNO3 solution containing HCl (HCl concentration 1 mol / L, AgNO3 concentration 1 mol / L) at 35℃ to generate...

[0072] AgCl / CNTs were collected by washing with ethanol and centrifuging several times after standing overnight to obtain pure AgCl / CNTs powder. Figure 2 This is a transmission electron microscope (TEM) image of the AgCl / CNTs powder prepared in Example 2, based on... Figure 2 It can be seen that silver chloride particles are uniformly loaded on the surface of carbon nanotubes.

[0073] (5) Add the resin to the organic solvent and stir using a high-speed disperser. The temperature should not exceed 70°C. After the resin is completely dissolved, cool it to room temperature and disperse it at high speed for 40 minutes to prepare an organic resin carrier. The mass fraction of the resin is 30%, and the mass fraction of the organic solvent is 70%. The resin is polyvinylidene chloride and chloroprene rubber, with a mass ratio of 1:1. The organic solvent is a mixture of dimethyl succinate, dimethyl glutarate, dimethyl adipate, and diethylene glycol butyl ether acetate, with a mass ratio of 1:1:1.5:2.

[0074] (6) Mix AgCl / CNTs powder and silver powder thoroughly to obtain mixed powder. Then grind and disperse the mixed powder with organic resin carrier in a three-roll mill. Finally, degas under reduced pressure to obtain nano-carbon-supported silver chloride composite slurry, wherein the mass fraction of AgCl / CNTs powder is 20%, the mass fraction of silver powder is 40%, and the mass fraction of organic resin carrier is 40%.

[0075] The prepared nano-carbon-supported silver chloride composite paste was printed onto polypropylene by screen printing. After printing, the electrode was heat-cured at 100℃ for 15 minutes to obtain a silver / silver chloride bioelectrode.

[0076] Example 3

[0077] (1) Take 1g of CNTs, add 75mL of concentrated nitric acid, heat and stir at 50℃ for 10h, then wash the CNTs mixture with deionized water, and filter several times to obtain pure functionalized CNTs.

[0078] (2) The functionalized CNTs were added to a solution of sodium dodecyl sulfate with a concentration of 1 g / L (the mass ratio of functionalized CNTs to surfactant was 7.5:2.5), and dispersed in an ultrasonic bath under ice bath conditions for 2 h to obtain a suspension of functionalized CNTs.

[0079] (3) The functionalized CNTs suspension was added to a 2 mol / L AgNO3 solution (the volume ratio of AgNO3 solution to functionalized CNTs suspension was 1:2.5) and stirred with a magnetic stirrer for 6 h. While stirring magnetically at room temperature, ascorbic acid was added dropwise to the above system at a rate of 20 mL / min (the molar ratio of silver nitrate to ascorbic acid was 1:8), and stirring was continued at room temperature for 0.5 h. Nano-silver was obtained by reduction on the surface of functionalized CNTs through a silver mirror reaction, thus preparing Ag / CNTs.

[0080] (4) At 50℃, Ag / CNTs were immersed in AgNO3 solution containing HCl (where the concentration of HCl was 1.5 mol / L and the concentration of AgNO3 was 1 mol / L) to chlorinate silver for 2 h to generate AgCl / CNTs. After standing overnight, the silver was washed with ethanol, centrifuged and collected several times to obtain pure AgCl / CNTs powder.

[0081] (5) Add the resin to the organic solvent and stir using a high-speed disperser. The temperature should not exceed 70°C. After the resin is completely dissolved, cool to room temperature and disperse at high speed for 40 minutes to prepare an organic resin carrier. The mass fraction of the resin is 40%, and the mass fraction of the organic solvent is 60%. The resin is polyvinylidene chloride and chloroprene rubber, with a mass ratio of polyvinylidene chloride to chloroprene rubber of 1:1.5. The organic solvent is a mixed solvent of dimethyl succinate, dimethyl glutarate, dimethyl adipate, and diethylene glycol butyl ether acetate, with a mass ratio of dimethyl succinate, dimethyl glutarate, dimethyl adipate, and diethylene glycol butyl ether acetate of 1:1.5:2:1.

[0082] (6) Mix AgCl / CNTs powder and silver powder thoroughly to obtain mixed powder. Then grind and disperse the mixed powder with organic resin carrier in a three-roll mill. Finally, degas under reduced pressure to obtain nano-carbon-supported silver chloride composite slurry, wherein the mass fraction of AgCl / CNTs powder is 25%, the mass fraction of silver powder is 50%, and the mass fraction of organic resin carrier is 25%.

[0083] The prepared nano-carbon-supported silver chloride composite paste was printed onto polypropylene by screen printing. After printing, the electrode was heat-cured at 85°C for 30 minutes to obtain a silver / silver chloride bioelectrode.

[0084] The bioelectrodes prepared in Examples 1-3 were subjected to performance testing, and the specific methods are as follows:

[0085] (1) Printing line width morphology:

[0086] The screen used for screen printing has a mesh count of 350, and the printing screen is selected with serpentine conductive lines of 0.6mm × 1m. After curing and cooling to room temperature, the edges of the conductive lines are observed in a 3D profilometer to see if they are straight. The line width is measured, and the extent of edge expansion is calculated. An edge expansion rate of ≤5% is considered to be excellent.

[0087] (2) Electrical performance testing

[0088] The resistance of the cured serpentine wire was tested using a Fluke 17B. + A multimeter and a film thickness gauge were used to test the resistance and film thickness of a 0.6mm wide silver wire. The resistivity of the slurry was obtained through the resistivity calculation formula, and the sheet resistance was further calculated.

[0089] (3) Adhesion test

[0090] Apply 3M adhesive tape to the cured cross-cut pattern, one tape in each direction (vertical and parallel). Smooth the tape with a high-quality drawing eraser. After 1 minute, pull the tape off vertically and quickly. Observe whether there is any residue stuck to the tape and pattern lines, and whether the film layer has been pulled off.

[0091] (4) Electrode self-noise test

[0092] A dual-electrode system was used in the electrochemical workstation to test the open-circuit potential of the electrodes. To reduce external interference, the test was conducted in a shielded room to detect its self-noise performance. The test frequency range was 0.01Hz to 10Hz.

[0093] (5) Electrode potential stability test

[0094] Electrochemical workstations were used to test the electrode potential stability in a 0.1 mol / L KCl solution. The specific test method is as follows: a two-electrode system was used, the open-circuit potential difference between the electrode and the counter electrode was measured, and the change of this potential value was recorded over a long period of time. The drift and fluctuation amplitude are the measure of stability. The measurement time was 12 hours.

[0095] The test results are shown in Table 1.

[0096] Table 1 Performance test results of the bioelectrodes prepared in Examples 1-3

[0097]

[0098]

[0099] The following conclusions can be drawn from Table 1:

[0100] The bioelectrode samples prepared by this invention exhibit excellent printing morphology, low sheet resistance, and good adhesion. They also demonstrate excellent self-noise performance in the low-frequency range (0.01Hz to 10Hz), indicating good electrical signal testing capabilities. Furthermore, the potential drift value is within 1mV per hour, demonstrating good stability and fully meeting the requirements for conventional bioelectrical signal measurement.

[0101] In summary, the electrodes printed using the nano-carbon-supported silver chloride composite paste provided by this invention exhibit low sheet resistance, good adhesion, good electrode potential stability, strong anti-interference ability, and good biocompatibility. Furthermore, they can be produced in specific shapes for different application environments, are low-cost, and easy to mass-produce. Simultaneously, the use of screen printing with low-temperature curing to prepare flexible electrodes avoids the drawbacks of existing silver / silver chloride bioelectrodes which require complex fabrication processes (such as high-voltage sheet forming). This not only reduces costs but, more importantly, facilitates industrial-scale mass production, significantly improving production efficiency compared to existing fabrication technologies.

[0102] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A nano-carbon-supported silver chloride composite slurry, characterized in that, The composition includes the following components by mass fraction: 10-25% AgCl / CNTs powder, 30-50% silver powder, and 25-60% organic resin carrier; wherein the AgCl / CNTs powder comprises carbon nanotubes and silver chloride particles supported on the carbon nanotubes.

2. The nano-carbon-supported silver chloride composite slurry according to claim 1, characterized in that, The preparation method of the AgCl / CNTs powder includes: Functionalized carbon nanotubes are obtained by acidifying carbon nanotubes. The functionalized carbon nanotubes and surfactant solution are mixed to obtain a functionalized carbon nanotube suspension. The functionalized carbon nanotube suspension and silver nitrate solution were mixed to obtain a mixed solution; The reducing agent and the mixture are mixed to carry out a reduction reaction, thereby obtaining carbon nanotubes loaded with silver nanoparticles. The carbon nanotubes loaded with silver nanoparticles were immersed in a chlorine-containing solution for chlorination treatment to obtain AgCl / CNTs powder.

3. The nano-carbon-supported silver chloride composite slurry according to claim 2, characterized in that, The acid used in the acidification treatment is concentrated nitric acid; the ratio of carbon nanotubes to concentrated nitric acid is 1g:50~100mL; the acidification temperature is 50~100℃ and the time is 5~10h; The surfactant in the surfactant solution includes one or both of sodium dodecylbenzenesulfonate and sodium dodecyl sulfate; the mass ratio of the functionalized carbon nanotubes to the surfactant is 7.5~9:1~2.

5.

4. The nano-carbon-supported silver chloride composite slurry according to claim 2, characterized in that, The concentration of the silver nitrate solution is 0.5~2 mol / L, and the volume ratio of the silver nitrate solution to the functionalized carbon nanotube suspension is 1:1~2.5; The reducing agent is one or more of formaldehyde, hydrazine hydrate, and ascorbic acid; the molar ratio of silver nitrate to reducing agent in the silver nitrate solution is 1:1.5~10.

5. The nano-carbon-supported silver chloride composite slurry according to claim 2, characterized in that, The chlorine-containing solution is a silver salt solution containing chloride, and the chloride is NaCl and / or HCl; the chlorination treatment is carried out at a temperature of 20~50℃ for a time of 0.5~2 h.

6. The nano-carbon-supported silver chloride composite slurry according to claim 1, characterized in that, The raw materials for preparing the organic resin carrier, by mass fraction, include: 55-75% organic solvent, 25-45% resin, and 0-5% curing agent; The resin includes one or more of polyvinylidene chloride, chloroprene rubber, chloroacetic acid resin, chloroether resin, modified phenolic resin, modified epoxy resin, modified cyanate ester resin, modified acrylic resin, and modified furfuryl alcohol resin; the curing agent includes one or more of imidazole, aliphatic amine, and isocyanate. The organic solvent includes one or more of butyl acetate, dimethyl succinate, dimethyl glutarate, dimethyl adipate, 2-ethylhexyl formate, ethanol, ethyl acetate, diethylene glycol ethyl ether acetate, cyclohexanone, ethylene glycol ethyl ether acetate, and ethylene glycol butyl ether acetate.

7. The nano-carbon-supported silver chloride composite slurry according to claim 6, characterized in that, The method for preparing the organic resin carrier includes: dissolving the resin in an organic solvent to obtain a resin solution; mixing the resin solution with a curing agent to obtain an organic resin carrier; when the amount of curing agent is 0, the step of mixing the resin solution and the curing agent is omitted.

8. The method for preparing the nano-carbon-supported silver chloride composite slurry according to any one of claims 1 to 7, characterized in that, Includes the following steps: AgCl / CNTs powder was mixed with silver powder to obtain a mixed powder; The mixed powder was ground and dispersed with an organic resin carrier to obtain a nano-carbon-supported silver chloride composite slurry.

9. The application of the nano-carbon-supported silver chloride composite slurry according to any one of claims 1 to 7 or the nano-carbon-supported silver chloride composite slurry prepared by the preparation method according to claim 8 in an electrode.

10. The application according to claim 9, characterized in that, The electrodes include biosensor electrodes, electrochemical reference electrodes, or electrocardiogram electrodes; The method of application includes: screen printing the nano-carbon silver chloride composite paste and then curing it to obtain an electrode; The curing temperature is 80~150℃ and the time is 5~30min.

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