Flexible sweat sensor, self-powered ECG-enabled smart clothing for continuous monitoring of sweat composition

Abstract

This invention provides a flexible sweat sensor and a self-powered smart garment for continuous monitoring of sweat composition via electrocardiogram (ECG). The flexible sweat sensor includes a flexible hollow tube shell with a micro-nano perforated structure and a component monitoring electrode encapsulated within the flexible hollow tube shell. The component monitoring electrode includes multiple yarn working electrodes and one yarn reference electrode. The flexible sweat sensor of this invention overcomes the fragility and wear-proneness of existing sensors made with conductive yarns. It is easier to integrate with clothing while preventing wear, extending service life, and providing a fast response speed. Furthermore, the self-powered smart garment for continuous monitoring of sweat composition via ECG provided by this invention allows for easy integration of the sensor with the clothing, flexible sensor placement, timely transmission of collected data, and long-term continuous monitoring.

Description

Technical Field

[0001] This invention belongs to the field of wearable flexible sensors and smart clothing technology, and in particular relates to a flexible sweat sensor and its preparation method, and a smart garment for continuous monitoring of sweat components via electrocardiogram. Background Technology

[0002] With the development of technology and people's increasing attention to their health, health monitoring methods are gradually shifting from professional settings such as medical institutions to everyday products like mobile phones and clothing. Unlike invasive monitoring methods, non-invasive health monitoring can monitor a range of physiological indicators on the human skin, such as electrocardiogram, electromyography, blood pressure, and sweat. The physiological information reflected by the measured substance is diverse and does not cause damage to the human body. Therefore, flexible sensors that enable non-invasive health monitoring have gained attention.

[0003] Current flexible sensors primarily use thin-film substrates, making integration with clothing difficult. Users must wear them directly against their skin, which can cause allergic reactions such as itching and redness with prolonged use. Therefore, combining flexible sensors with clothing to create more wearable health monitoring garments is an important research direction. While technologies combining sensors for monitoring physiological indicators with clothing have emerged, problems remain, including poor integration, complex integration processes, limited sensor placement, inability to achieve long-term continuous monitoring, and the inability to transmit collected data promptly.

[0004] In addition, existing technologies have used conductive yarns to improve the electrochemical performance of electrodes, which makes them easier to integrate with clothing. However, the surface of the yarn itself is relatively fragile, and the sensor performance will degrade during daily wear and tear. Therefore, the application of such sensors made with conductive yarns is still greatly limited. Summary of the Invention

[0005] In view of this, to solve the above problems, the present invention proposes a flexible sweat sensor. The flexible sweat sensor overcomes the fragility and wear-proneness of existing sensors made of conductive yarn. It is easier to integrate with clothing, while preventing wear, extending service life, and having a fast response speed. The present invention also provides a method for preparing the flexible sweat sensor. In addition, the present invention provides a smart garment that allows for easy integration of the sensor with clothing, flexible sensor integration location, timely transmission of collected data, and long-term continuous monitoring of sweat composition via electrocardiogram.

[0006] To achieve the above objectives, the technical solution of the present invention is implemented as follows:

[0007] The present invention provides a flexible sweat sensor, comprising a flexible hollow tube shell with a micro-nano through-hole structure, and a component monitoring electrode encapsulated by the flexible hollow tube shell; the component monitoring electrode comprises multiple yarn working electrodes and a yarn reference electrode.

[0008] The flexible sweat sensor is made based on yarn electrodes, which has the advantage of being easily integrated with clothing. At the same time, it is encapsulated in a flexible hollow tube shell with a micro-nano porous structure. The flexibility of the hollow tube shell itself does not affect the integration with clothing, and it can effectively protect the component monitoring electrodes inside, prevent wear, improve stability, and extend service life. In addition, because the flexible hollow tube shell has a micro-nano porous structure, sweat can penetrate into the component monitoring electrodes without affecting the response time.

[0009] In some preferred embodiments of the flexible sweat sensor of the present invention, the yarn working electrode includes a conductive yarn as an electrode material and a conductive polymer layer coated on the conductive yarn by electrochemical deposition.

[0010] In some preferred embodiments of the flexible sweat sensor of the present invention, the conductive yarn is carbon yarn, carbon nanotube yarn, or gold-plated filament.

[0011] In some preferred embodiments of the flexible sweat sensor of the present invention, the conductive polymer layer is polythiophene or polyaniline.

[0012] In some more preferred embodiments of the flexible sweat sensor of the present invention, the length of the conductive yarn is 4 to 5 cm, and the length of the conductive polymer layer is 2 to 3 cm.

[0013] In some preferred embodiments of the flexible sweat sensor of the present invention, the yarn reference electrode is a silver / silver chloride yarn reference electrode prepared by electrochemical deposition.

[0014] In some preferred embodiments of the flexible sweat sensor of the present invention, the flexible sweat sensor further includes a sweat drainage layer, which is a coating structure formed by wrapping absorbent yarn around the surface of the component monitoring electrode; the absorbent yarn is wrapped around the surface of the yarn reference electrode and the surface of each yarn working electrode.

[0015] The sweat drainage layer can collect and drain sweat, further shortening the response time of the flexible sweat sensor.

[0016] The sweat drainage layer can be formed by sequentially wrapping a single absorbent yarn around each yarn electrode in the component monitoring electrode. Using a single absorbent yarn to wrap each yarn electrode in the component monitoring electrode can not only cover each yarn electrode in the component monitoring electrode, which is conducive to the collection and introduction of sweat, but also fix the yarn reference electrode and multiple yarn working electrodes.

[0017] In some preferred embodiments of the flexible sweat sensor of the present invention, the absorbent yarn is cotton yarn, bamboo fiber yarn, or moisture-wicking and quick-drying yarn.

[0018] In some preferred embodiments of the flexible sweat sensor of the present invention, the flexible hollow tube shell includes an encapsulation surface layer and a component monitoring layer covered by the encapsulation surface layer.

[0019] In some preferred embodiments of the flexible sweat sensor of the present invention, the encapsulation surface layer is made of TPU (thermoplastic polyurethane); the component monitoring layer is made of PANI (polyaniline).

[0020] In some more preferred embodiments of the flexible sweat sensor of the present invention, the flexible hollow tube shell is prepared by the following steps:

[0021] S1. Micro-nano porous structure templates were prepared using anodized aluminum oxide process;

[0022] S2. A polyaniline coating was applied to the surface of a micro / nano porous structure template by in-situ polymerization to obtain an AAO / PANI conductive template.

[0023] S3. Coat the surface of the AAO / PANI conductive template with a TPU encapsulation layer to obtain the AAO / PANI / TPU aluminum wire conductive template;

[0024] S4. Remove the aluminum base and AAO template from the AAO / PANI / TPU aluminum wire conductive template to obtain a flexible hollow tube shell with a PANI / TPU micro-nano through-hole structure.

[0025] In some more preferred embodiments of the flexible sweat sensor of the present invention,

[0026] S1 specifically comprises: S1.1, performing the following pretreatment steps on the aluminum wire in sequence: cleaning, removing the natural aluminum oxide layer on the surface, and electrochemical polishing to obtain a flat and smooth aluminum wire; S1.2, pre-oxidizing the flat and smooth aluminum wire; S1.3, removing the aluminum oxide film generated by pre-oxidation, leaving regular pits formed by pre-oxidation on the surface of the aluminum wire; S1.4, anodizing the aluminum wire with regular pits on the surface, and then performing pore-expanding treatment to obtain a micro-nano through-hole structure template;

[0027] S2 specifically involves: S2.1, adding the aniline monomer solution to the p-toluenesulfonic acid solution and stirring until homogeneous; S2.2, placing the micro / nano porous structure template into the solution prepared in S2.1, allowing the aniline monomer to be uniformly adsorbed onto the surface of the micro / nano porous structure template; S2.3, adding an oxidant solution to the solution in S2.2 to carry out an in-situ polymerization reaction of aniline. After in-situ polymerization of aniline, the micro / nano porous structure template is removed, dried, and the AAO / PANI conductive template is obtained.

[0028] S3 specifically includes: S3.1, preparing a TPU / DMF mixed solution and degassing under vacuum; S3.2, immersing the AAO / PANI conductive template in the TPU / DMF mixed solution and evacuating it, then taking it out and keeping it at 120°C under vacuum. After TPU curing, an AAO / PANI / TPU aluminum wire conductive template is obtained.

[0029] S4 specifically comprises: S4.1, placing the AAO / PANI / TPU aluminum wire conductive template in a mixed solution of hydrochloric acid and copper chloride to remove the aluminum base, thereby obtaining the AAO / PANI / TPU conductive template; S4.2, placing the AAO / PANI / TPU conductive template in a mixed solution of phosphoric acid and distilled water to remove the AAO template, thereby obtaining a flexible hollow tube shell with a PANI / TPU micro / nano through-hole structure.

[0030] In some preferred embodiments of the flexible sweat sensor of the present invention, in step S1.1, the electrochemical polishing uses a polishing solution with a volume ratio of perchloric acid to anhydrous ethanol of 1:2 to 1:8, and the polishing voltage is 10 to 30V; after polishing, it is rinsed with distilled water; in step S1.2, the pre-oxidation uses an oxidizing solution of 0.1 to 5 wt% phosphoric acid and 0.01 to 1 mol / L oxalic acid, the pre-oxidation time is 1 to 6 hours, and the oxidation voltage is 150 to 200V; in step S1.3, the... An aluminum wire with an alumina film is placed in a mixed solution of 10-20 g / L chromium trioxide and 1-10 wt% phosphoric acid, and kept at a constant temperature of 50-80°C in a water bath for 2-5 hours to remove the alumina film. After removal, the wire is rinsed with distilled water and dried. In step S1.4, an anodizing is performed on the aluminum wire with regular pits on the surface using an initial voltage of 150-200V. The anodized aluminum wire is then subjected to a pore-expanding treatment at 20-40°C with a 1-10 wt% phosphoric acid solution for 120-300 minutes.

[0031] In some preferred embodiments of the flexible sweat sensor of the present invention, in step S2.3, the oxidant solution is an ammonium persulfate solution; the polyaniline coating thickness in the obtained AAO / PANI conductive template is 200-500 nm, the diameter of the through holes in the polyaniline coating is 300-500 nm, the hole spacing is 500-600 nm, and the pore density is 3-5 × 10⁻⁶. 8 .

[0032] In some more preferred embodiments of the flexible sweat sensor of the present invention, in step S3.1, the mass concentration of TPU in the TPU / DMF mixed solution is 5-20%.

[0033] In some more preferred embodiments of the flexible sweat sensor of the present invention, in step S4.1, the mass concentration of hydrochloric acid in the mixed solution of hydrochloric acid and copper chloride is 5-20%, and the molar concentration of copper chloride is 0.05-0.5 mol / L; in step S4.2, the volume ratio of phosphoric acid to distilled water in the mixed solution of phosphoric acid and distilled water is 1:1 to 1:3.

[0034] A second aspect of the present invention provides a method for preparing a flexible sweat sensor, comprising the following preparation steps:

[0035] Step 1: Prepare a flexible hollow tube shell with a micro / nano-porous structure using the steps described above.

[0036] Step 2: Insert and fix multiple working yarn electrodes and one reference yarn electrode, which serve as component monitoring electrodes, into the flexible hollow tube shell to obtain the flexible sweat sensor.

[0037] In some preferred embodiments of the preparation method of the flexible sweat sensor of the present invention, the component monitoring electrode is covered with a sweat drainage layer; the sweat drainage layer is a coating structure formed by wrapping absorbent yarn around the surface of the component monitoring electrode; the absorbent yarn is wrapped around the surface of the yarn reference electrode and the surface of each yarn working electrode.

[0038] A third aspect of the present invention provides an application of a flexible sweat sensor in wearable health monitoring clothing.

[0039] A fourth aspect of this invention provides a self-powered smart garment for continuous monitoring of sweat composition and electrocardiogram (ECG) data, comprising a garment body, a sweat sensor, a fabric ECG sensor, a yarn battery, and a wireless data transmission module fixed to the garment body; both the sweat sensor and the fabric ECG sensor are electrically connected to the wireless data transmission module via wires, transmitting the collected information to the wireless data transmission module; the yarn battery powers the wireless data transmission module; the sweat sensor is the flexible sweat sensor described above, and the component monitoring electrode of the flexible sweat sensor is connected to the wireless data transmission module via wires; the wireless data transmission module can wirelessly transmit the collected information to a backend receiving and processing module, such as corresponding software on a mobile phone.

[0040] The sensors in self-powered smart clothing that continuously monitors ECG and sweat composition are designed based on yarn or fabric, making it easier to integrate with the clothing itself. The sensors can be placed anywhere on the clothing, allowing for flexible integration. It also features a wireless data transmission module and a yarn battery, enabling integrated power supply, data acquisition, and transmission.

[0041] In some preferred embodiments of the smart clothing for continuous monitoring of electrocardiogram sweat composition according to the present invention, the clothing body is an elastic tight-fitting structure that can fit snugly against the skin when worn.

[0042] In some preferred embodiments of the smart clothing for continuous monitoring of electrocardiogram sweat composition according to the present invention, the material of the clothing body is one or a blend of polyester, spandex, and nylon.

[0043] In some preferred embodiments of the smart garment for continuous monitoring of electrocardiogram and sweat composition according to the present invention, the sweat sensor, the fabric electrocardiogram sensor, the yarn battery, and the wireless data transmission module are all fixed to the garment body by heat pressing, sewing, or bonding.

[0044] In some preferred embodiments of the smart garment for continuous monitoring of sweat components and electrocardiogram (ECG) of the present invention, the fabric ECG sensor includes a plurality of silver-plated fabric ECG electrodes, which can be distributed at any position on the garment body according to actual conditions.

[0045] In some preferred embodiments of the smart garment for continuous monitoring of sweat components of the electrocardiogram (ECG) of the present invention, the silver-plated fabric ECG electrode includes a sponge pad, a copper foil electrode covering the outer surface of the sponge pad, a wire connected to the copper foil electrode, and a silver-plated fabric covering the copper foil electrode.

[0046] In some more preferred embodiments of the smart garment for continuous monitoring of sweat components of self-powered electrocardiogram (ECG) of the present invention, the silver-plated fabric ECG electrode further includes an adhesive layer attached to the surface of the silver-plated fabric and which can fix the silver-plated fabric ECG electrode to the garment body; preferably, the adhesive layer is a cloth-based adhesive tape.

[0047] In some preferred embodiments of the self-powered smart garment for continuous monitoring of ECG and sweat composition according to the present invention, the yarn battery is a yarn-shaped nickel battery, with nickel-plated @cobalt-nickel hydroxide yarn as the positive electrode and zinc-plated yarn as the negative electrode; the nickel-plated @cobalt-nickel hydroxide yarn is deposited on the surface of a double-strand silver-plated yarn by electrochemical deposition, and then converted into nickel-plated @cobalt-nickel hydroxide yarn by electrochemical deposition; the zinc-plated yarn is deposited on the surface of a double-strand silver-plated yarn by electrochemical deposition.

[0048] The preparation process of the nickel-plated@cobalt-nickel hydroxide yarn is as follows:

[0049] Step 1: Use NiCl2 and NH4Cl as electrodeposition solutions to pre-soak the double-strand silver-plated yarn for 10-30 minutes;

[0050] Step 2: Using a saturated calomel electrode as the reference electrode and a platinum sheet electrode as the counter electrode, set the voltage to -1.0V, and electrochemically deposit a nickel layer on the double-strand silver-plated yarn in a NiCl2 and NH4Cl electrodeposition solution for a deposition time of 200–800 s.

[0051] Step 3: Using Ni(NO3)2 and Co(NO3)2 as electrodeposition solutions, and setting the voltage to -1.0V, an island-bridge-shaped cobalt-nickel hydroxide shell is deposited on the nickel / silver yarn obtained in Step 2. The deposition time is 50-150s, resulting in nickel-plated @cobalt-nickel hydroxide yarn as the positive electrode.

[0052] The preparation process of the galvanized yarn is as follows:

[0053] Step 1: Prepare an electrodeposition solution using Na2[Zn(OH)4], ZnO, NaOH and zinc powder, and pre-soak the double-strand silver-plated yarn for 10-30 minutes.

[0054] Step 2: Using a saturated calomel electrode as the reference electrode and a platinum sheet electrode as the counter electrode, set the current density to 1 mA / cm². -1 Electrochemical deposition of a nickel layer was performed on silver-plated yarn in NiCl2 and NH4Cl electrodeposition solutions for 10–50 min to obtain zinc-plated yarn as the negative electrode.

[0055] The yarn-shaped nickel battery has good flexibility and can be sewn onto clothing.

[0056] Compared with existing technologies, the flexible sweat sensor and self-powered smart clothing for continuous monitoring of sweat composition via electrocardiogram described in this invention have the following advantages:

[0057] (1) The flexible sweat sensor described in this invention retains the advantage of yarn electrodes being easily integrated with clothing, and effectively protects the component monitoring electrode through the flexible hollow tube shell with micro-nano through-hole structure, preventing wear, improving stability, and extending service life. At the same time, since the flexible hollow tube shell has a micro-nano through-hole structure, sweat can penetrate into the component monitoring electrode without affecting the response time, and the electrode sensitivity is high.

[0058] (2) The flexible sweat sensor of the present invention is provided with a sweat drainage layer, which can collect and drain sweat, thereby further shortening the response time of the flexible sweat sensor;

[0059] (3) The sensors of the self-powered smart garment for continuous monitoring of ECG and sweat composition described in this invention are all designed based on yarn or fabric, making it easier to integrate with the garment body; the sensors can be set at any position on the garment body, and the integration position is free; it is equipped with a wireless data transmission module and a yarn battery, which can transmit the collected data to the outside in a timely manner and can also realize long-term continuous monitoring. Attached Figure Description

[0060] Figure 1 This is a schematic diagram of the cross-sectional structure of the flexible sweat sensor described in Example 1;

[0061] Figure 2 This is a schematic diagram of the flexible sweat sensor described in Example 1;

[0062] Figure 3 This is a SEM image of the micro-nano through-hole structure of the flexible hollow tube shell (before TPU encapsulation) described in Example 1;

[0063] Figure 4 This is a comparison chart of electrode sensitivity tests during performance testing;

[0064] Figure 5 This is a comparison chart of response time tests in performance testing;

[0065] Figure 6 Sensitivity diagrams of sodium and potassium ion selective electrodes used in performance testing;

[0066] Figure 7 This is a schematic diagram of the structure of the self-powered smart garment for continuous monitoring of ECG sweat composition as described in Example 3;

[0067] Figure 8 This is a schematic diagram of the structure of the silver-plated fabric electrocardiogram electrode described in Example 3;

[0068] Figure 9 This is a schematic diagram of the yarn-shaped nickel battery described in Example 3;

[0069] Figure 10 This is a SEM image of the cobalt-nickel hydroxide on the surface of the yarn-shaped nickel battery described in Example 3.

[0070] Explanation of reference numerals in the attached figures:

[0071] 1- Flexible hollow tube shell, 2- Sweat drainage layer, 3- Yarn working electrode, 4- Yarn reference electrode, 5- Absorbent yarn, 6- Garment body, 7- Sweat sensor, 8- Yarn battery, 9- Wireless data transmission module, 10- Silver-plated fabric ECG electrode, 11- Sponge pad, 12- Copper foil electrode, 13- Silver-plated fabric, 14- Cloth tape. Detailed Implementation

[0072] Unless otherwise defined, the technical terms used in the following embodiments have the same meanings as commonly understood by those skilled in the art. Unless otherwise specified, the experimental reagents used in the following embodiments are conventional biochemical reagents; and the experimental methods described are conventional methods.

[0073] The present invention will now be described in detail with reference to the embodiments and accompanying drawings.

[0074] Example 1: Flexible Sweat Sensor

[0075] like Figures 1 to 3 As shown, the flexible sweat sensor includes a flexible hollow tube shell 1 with a micro-nano through-hole structure, and a component monitoring electrode and a sweat drainage layer 2 encapsulated by the flexible hollow tube shell 1.

[0076] The composition monitoring electrode includes three yarn working electrodes 3 and one yarn reference electrode 4. The yarn working electrode 3 includes a conductive yarn as the electrode material and a conductive polymer layer coated on the conductive yarn by electrochemical deposition. The conductive yarn is carbon yarn, and the conductive polymer layer is polythiophene. The length of the conductive yarn is 4 cm, and the length of the conductive polymer layer is 2 cm. The yarn reference electrode 4 is a silver / silver chloride yarn reference electrode prepared by electrochemical deposition.

[0077] The sweat drainage layer 2 is a coating structure formed by wrapping the surface of the component monitoring electrode with absorbent yarn 5. The absorbent yarn 5 is a moisture-wicking and quick-drying yarn. One absorbent yarn 5 is used to wrap the surface of the yarn reference electrode 4 and the surface of each yarn working electrode 3 in sequence. The two ends of the absorbent yarn 5 and the two ends of the component monitoring electrode can extend out of the flexible hollow tube shell 1. The flexible hollow tube shell 1 encapsulates and fixes them. Both ends can extend slightly, or one end can extend slightly, or neither end can extend.

[0078] The flexible hollow tube shell 1 has a micro-nano through-pore structure (see...) Figure 3 The product includes an encapsulation surface layer and a component monitoring layer covered by the encapsulation surface layer; the encapsulation surface layer is made of TPU; the component monitoring layer is made of PANI.

[0079] The flexible hollow tube outer shell 1 is prepared by the following method:

[0080] Step 1: Fabrication of micro / nano-porous structure templates using anodized aluminum process:

[0081] (1) Cut the aluminum wire into segments, ultrasonically clean it with acetone solution, rinse it with distilled water, then put the aluminum wire into a 1 mol / L NaOH solution and react for 10 min to remove the natural aluminum oxide layer on the surface of the aluminum wire. Rinse it with distilled water and dry the aluminum wire to prevent it from being naturally oxidized again in the air in a humid environment. Perform electrochemical polishing on the aluminum wire using a polishing solution with a volume ratio of perchloric acid to anhydrous ethanol of 1:2 to 1:8, set the polishing voltage to 21V, and the time to 5 min. After polishing, rinse with distilled water to obtain a flat and smooth aluminum wire.

[0082] (2) The aluminum wire with a flat and smooth surface is pre-oxidized. The oxidation solution used is a mixture of 1wt% phosphoric acid and 0.01-1mol / L oxalic acid. The pre-oxidation time is 4h and the oxidation voltage is 195V.

[0083] (3) Remove the pre-oxidized alumina film. The pre-oxidized regular pits are left on the surface of the aluminum wire, which provide the growth direction for the subsequent anodizing to form micro-nano through-hole structure. The alumina film is removed by a mixed solution of 18 g / L chromium trioxide and 6 wt% phosphoric acid. The water bath is kept at 60℃ for 3 h 50 min. After removing the alumina film, it is taken out, rinsed with distilled water, and dried.

[0084] (4) Anodize the aluminum wire with regular pits on the surface with an initial voltage of 195V; then, use 5wt% phosphoric acid solution and water bath heating at 30℃ to expand the pore size for 180min to provide a basis for subsequent material filling and obtain micro-nano through-hole structure template.

[0085] Step 2: Coat the surface of the micro / nano porous structure template with a polyaniline coating (composition monitoring layer) using in-situ polymerization to obtain the AAO / PANI conductive template;

[0086] (1) Place the aniline monomer solution into the p-toluenesulfonic acid solution and stir until homogeneous;

[0087] (2) Place the micro-nano through-hole structure template into the solution prepared in (1) and stir at a constant speed to make the aniline monomer uniformly adsorbed on the surface of the micro-nano through-hole structure template.

[0088] (3) Add an oxidant solution to the solution in (2) to carry out an in-situ polymerization reaction of aniline. After the in-situ polymerization of aniline, take out the micro-nano through-hole structure template and air dry it in a ventilated place to obtain the AAO / PANI conductive template. The oxidant solution is made by dissolving ammonium persulfate in p-toluenesulfonic acid solution.

[0089] Step 3: Coat the surface of the AAO / PANI conductive template with a TPU encapsulation layer (encapsulation surface layer) to obtain the AAO / PANI / TPU aluminum wire conductive template.

[0090] (1) Prepare a TPU / DMF mixed solution with a TPU mass concentration of 10%, place the mixed solution in a water bath at 60℃ and heat and stir for 3 hours, and then degas the mixed solution under vacuum.

[0091] (2) Immerse the AAO / PANI conductive template in the TPU / DMF mixed solution and vacuum for 5 minutes. Then take it out and put it in a vacuum oven. Keep it at 120°C for 120 minutes under vacuum. After TPU curing, you will get the AAO / PANI / TPU aluminum wire conductive template.

[0092] Step 4: Remove the aluminum base and AAO template from the AAO / PANI / TPU aluminum wire conductive template to obtain a flexible hollow tube shell with a PANI / TPU micro / nano through-hole structure.

[0093] (1) The aluminum-based AAO / PANI / TPU aluminum wire conductive template was placed in a mixed solution of hydrochloric acid and copper chloride to remove the aluminum base. The mass concentration of hydrochloric acid in the mixed solution of hydrochloric acid and copper chloride was 10%, and the molar concentration of copper chloride was 0.1 mol / L, thus obtaining the AAO / PANI / TPU conductive template.

[0094] (2) The AAO / PANI / TPU conductive template was placed in a mixed solution of phosphoric acid and distilled water to remove the AAO template. The volume ratio of phosphoric acid to distilled water in the mixed solution of phosphoric acid and distilled water was 1:1, and a flexible hollow tube shell 1 with a micro-nano through-hole structure of PANI / TPU was obtained.

[0095] Example 2 Flexible sweat sensor

[0096] Based on Example 1, the difference from Example 1 is that the sweat drainage layer 2 is not provided.

[0097] Performance testing:

[0098] 1. Electrode sensitivity test

[0099] Comparative Example 1: Based on Example 1, but unlike Example 1, a planar PANI / TPU hollow tube without micro-nano pores was used to replace the flexible hollow tube shell with micro-nano pores to prepare a sweat sensor.

[0100] The flexible sweat sensor with a flexible hollow tube shell and a micro / nano porous structure prepared in Example 1 was compared with the sweat sensor prepared in Comparative Example 1 by electrode sensitivity testing. The test results are shown in [Figure 1]. Figure 4 .Depend on Figure 4It can be seen that the sensitivity of the flexible sweat sensor prepared in Example 1 is much higher than that of the sweat sensor prepared in Comparative Example 1. This is mainly because the flexible sweat sensor prepared in Example 1 uses a flexible hollow tube shell with a micro-nano through-pore structure. Compared with a planar polyaniline / TPU film that is only hollow tubular but has no microstructure, this micro-nano through-pore structure can effectively increase the speed of sweat entering and leaving the tube, thereby improving the sensitivity and response time of the sensor.

[0101] 2. Response time test

[0102] The response time of the flexible sweat sensor prepared in Example 1 and the flexible sweat sensor prepared in Example 2 were compared. Example 1 had a sweat-draining layer composed of moisture-absorbing and quick-drying yarn, while Example 2 did not have a sweat-draining layer. The test results are shown in [the table below]. Figure 5 .Depend on Figure 5 It is known that setting up a sweat drainage layer will shorten the response time. The sweat drainage layer can collect and drain sweat, and can guide the sweat to the component monitoring electrode more quickly.

[0103] 3. Sensitivity of sodium and potassium ion selective electrodes

[0104] The yarn working electrode is a selective electrode made of carbon yarn and conductive polymer, targeting the main ions in sweat, such as... Figure 6 As shown, taking the monitoring of sodium and potassium ions in sweat as an example, the sodium and potassium ion selective electrodes made of carbon yarn and conductive polymer have sensitivities that conform to the Nernst equation, and their response range covers the physiological concentration range of the corresponding ions in human sweat.

[0105] Example 3: Self-Powered Smart Clothing for Continuous Monitoring of ECG and Sweat Components

[0106] like Figure 7 As shown, the self-powered smart garment for continuous monitoring of ECG and sweat composition includes a garment body 6, a sweat sensor 7 fixed on the garment body 6, a fabric ECG sensor, a yarn battery 8, and a wireless data transmission module 9.

[0107] The garment body 6 has an elastic, tight-fitting structure that fits snugly against the skin when worn, and is made of polyester.

[0108] The sweat sensor 7 is a flexible sweat sensor prepared in Example 1. The position can be fixed at the position of the garment body 6 where there is more sweat, depending on the actual situation. The component monitoring electrode of the flexible sweat sensor is electrically connected to the wireless data transmission module 9 through a wire, and transmits the collected sweat data to the wireless data transmission module 9.

[0109] The fabric ECG sensor includes three silver-plated fabric ECG electrodes 10, whose positions can be selected and fixed on the garment body 6 at locations conducive to ECG acquisition, depending on the actual situation; for example... Figure 8 As shown, the silver-plated fabric ECG electrode 10 includes a sponge pad 11, a copper foil electrode 12 covering the outer surface of the sponge pad 11, a wire connected to the copper foil electrode 12, and a silver-plated fabric 13 covering the copper foil electrode 12; the surface of the silver-plated fabric 13 is provided with a cloth-based adhesive tape 14 for fixing the silver-plated fabric ECG electrode 10 to the garment body 6; the silver-plated fabric ECG electrode 10 is electrically connected to the wireless data transmission module 9 through the wire on the copper foil electrode 12, and transmits the collected ECG data to the wireless data transmission module 9;

[0110] The yarn battery 8 powers the wireless data transmission module 9. The yarn battery 8 has good flexibility and can be fixed to clothing by sewing; the yarn battery 8 is a yarn-shaped nickel battery, such as... Figure 9 and 10 As shown, the yarn-shaped nickel battery uses nickel-plated@cobalt-nickel hydroxide yarn as the positive electrode and zinc-plated yarn as the negative electrode. The nickel-plated@cobalt-nickel hydroxide yarn is deposited on the surface of the double-strand silver-plated yarn by electrochemical deposition, and then converted into nickel-plated@cobalt-nickel hydroxide yarn by electrochemical deposition. The zinc-plated yarn is deposited on the surface of the double-strand silver-plated yarn by electrochemical deposition.

[0111] The preparation process of nickel-plated @ cobalt-nickel hydroxide yarn is as follows:

[0112] Step 1: Use NiCl2 and NH4Cl as electrodeposition solutions to pre-soak the double-strand silver-plated yarn for 20 minutes;

[0113] Step 2: Using a saturated calomel electrode as the reference electrode and a platinum sheet electrode as the counter electrode, set the voltage to -1.0V, and electrochemically deposit a nickel layer on the double-strand silver-plated yarn in a NiCl2 and NH4Cl electrodeposition solution for 500s.

[0114] Step 3: Using Ni(NO3)2 and Co(NO3)2 as electrodeposition solutions, and setting the voltage to -1.0V, an island-bridge-shaped cobalt-nickel hydroxide shell is deposited on the nickel / silver yarn obtained in Step 2. The deposition time is 100s, resulting in nickel-plated @ cobalt-nickel hydroxide yarn as the positive electrode.

[0115] The preparation process of the galvanized yarn is as follows:

[0116] Step 1: Prepare an electrodeposition solution using Na2[Zn(OH)4], ZnO, NaOH and zinc powder, and pre-soak the double-strand silver-plated yarn for 20 minutes;

[0117] Step 2: Using a saturated calomel electrode as the reference electrode and a platinum sheet electrode as the counter electrode, set the current density to 1 mA / cm². -1 Electrochemical deposition of a nickel layer was performed on silver-plated yarn in a NiCl2 and NH4Cl electrodeposition solution for 20 minutes to obtain zinc-plated yarn as the negative electrode.

[0118] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A flexible sweat sensor, characterized in that: The invention includes a flexible hollow tube shell with a micro-nano through-hole structure, and a composition monitoring electrode encapsulated by the flexible hollow tube shell; the composition monitoring electrode includes multiple yarn working electrodes and a yarn reference electrode. The flexible hollow tube shell includes an outer encapsulation layer and a component monitoring layer covered by the encapsulation layer. The encapsulation layer is made of TPU, and the component monitoring layer is made of PANI. The flexible hollow tube outer shell is prepared through the following steps: S1. Micro-nano porous structure templates were prepared using anodized aluminum oxide process; S2. An AAO / PANI conductive template is obtained by coating a polyaniline layer onto the surface of a micro / nano porous structure template using an in-situ polymerization method; the front pore diameter of the polyaniline layer in the AAO / PANI conductive template is 300-500 nm. S3. Coat the surface of the AAO / PANI conductive template with a TPU encapsulation layer to obtain the AAO / PANI / TPU aluminum wire conductive template; S4. Remove the aluminum base and AAO template from the AAO / PANI / TPU aluminum wire conductive template to obtain a flexible hollow tube shell with a PANI / TPU micro-nano through-hole structure.

2. The flexible sweat sensor according to claim 1, characterized in that: The yarn working electrode includes a conductive yarn as the electrode material and a conductive polymer layer coated on the conductive yarn by electrochemical deposition. The conductive yarn is carbon yarn, carbon nanotube yarn, or gold-plated filament. The conductive polymer layer is polythiophene or polyaniline; The conductive yarn has a length of 4-5 cm, and the conductive polymer layer has a length of 2-3 cm.

3. The flexible sweat sensor according to claim 1, characterized in that: The yarn reference electrode is a silver / silver chloride yarn reference electrode prepared by electrochemical deposition.

4. The flexible sweat sensor according to claim 1, characterized in that: The flexible sweat sensor also includes a sweat drainage layer, which is a coating structure formed by wrapping absorbent yarn around the surface of the component monitoring electrode; the absorbent yarn is wrapped around the surface of the yarn reference electrode and the surface of each yarn working electrode. The absorbent yarn is cotton yarn, bamboo fiber yarn, or moisture-wicking and quick-drying yarn.

5. The flexible sweat sensor according to claim 1, characterized in that: Specifically, S1 is: S1.1 The aluminum wire is subjected to the following pretreatment steps in sequence: cleaning, removing the natural aluminum oxide layer on the surface, and electrochemical polishing to obtain a flat and smooth aluminum wire; S1.2 Pre-oxidize the aluminum wire with a flat and smooth surface; S1.3 Remove the aluminum oxide film generated by pre-oxidation, leaving regular pits formed by pre-oxidation on the surface of the aluminum wire; S1.

4. The aluminum wire with regular pits on the surface is anodized and then enlarged to obtain a micro-nano through-hole structure template. Specifically, S2 is: S2.

1. Place the aniline monomer solution into the p-toluenesulfonic acid solution and stir until homogeneous; S2.2 Place the micro / nano porous structure template into the solution prepared in S2.1 to allow the aniline monomer to be uniformly adsorbed on the surface of the micro / nano porous structure template. S2.3 Add an oxidant solution to the solution in S2.2 to carry out the in-situ polymerization reaction of aniline. After the in-situ polymerization of aniline, take out the micro-nano through-hole structure template, dry it, and obtain the AAO / PANI conductive template. Specifically, S3 is: S3.

1. Prepare a TPU / DMF mixed solution and degas it under vacuum; S3.

2. Immerse the AAO / PANI conductive template in a TPU / DMF mixed solution and evacuate it. Then take it out and keep it at 120 ℃ under vacuum. After TPU curing, the AAO / PANI / TPU aluminum wire conductive template is obtained. Specifically, S4 is: S4.1 Place the AAO / PANI / TPU aluminum wire conductive template in a mixed solution of hydrochloric acid and copper chloride to remove the aluminum base, and obtain the AAO / PANI / TPU conductive template; S4.

2. The AAO / PANI / TPU conductive template is placed in a mixed solution of phosphoric acid and distilled water to remove the AAO template, thereby obtaining a flexible hollow tube shell with a PANI / TPU micro-nano through-pore structure. In step S1.1, the electrochemical polishing uses a polishing solution with a volume ratio of perchloric acid to anhydrous ethanol of 1:2 to 1:8, and the polishing voltage is 10 to 30 V; after polishing, the surface is rinsed with distilled water. In step S1.2, the oxidizing solution used for pre-oxidation is a mixture of 0.1–5 wt% phosphoric acid and 0.01–1 mol / L oxalic acid, the pre-oxidation time is 1–6 h, and the oxidation voltage is 150–200 V; In step S1.3, the aluminum wire with the alumina film is placed in a mixed solution of 10-20 g / L chromium trioxide and 1-10 wt% phosphoric acid, and kept at a constant temperature of 50-80 ℃ in a water bath for 2-5 hours to remove the alumina film. After removal, it is rinsed with distilled water and dried. In step S1.4, an initial voltage of 150-200V is used to anodize the aluminum wire with regular pits on the surface; then the anodized aluminum wire is subjected to a pore-expanding treatment at 20-40°C with a 1-10 wt% phosphoric acid solution for 120-300 minutes. In step S2.3, the oxidant solution is an ammonium persulfate solution; the polyaniline coating thickness in the obtained AAO / PANI conductive template is 200–500 nm, the pore spacing is 500–600 nm, and the pore density is 3–5 × 10⁻⁶. 8 ; In step S3.1, the mass concentration of TPU in the TPU / DMF mixed solution is 5-20%; In step S4.1, the mass concentration of hydrochloric acid in the mixed solution of hydrochloric acid and copper chloride is 5-20%, and the molar concentration of copper chloride is 0.05-0.5 mol / L. In step S4.2, the volume ratio of phosphoric acid to distilled water in the mixed solution of phosphoric acid and distilled water is 1:1 to 1:

3.

6. A method for preparing a flexible sweat sensor, characterized in that, The preparation steps include the following: Step 1: Prepare a flexible hollow tube shell with a micro / nano-porous structure using the steps described in claim 1 or 5. Step 2: Insert and fix multiple working yarn electrodes and one reference yarn electrode, which serve as component monitoring electrodes, into the flexible hollow tube shell to obtain the flexible sweat sensor; The component monitoring electrode is covered with a sweat drainage layer; the sweat drainage layer is a coating structure formed by wrapping absorbent yarn around the surface of the component monitoring electrode; the absorbent yarn is wrapped around the surface of the yarn reference electrode and the surface of each yarn working electrode.

7. The use of the flexible sweat sensor according to any one of claims 1 to 5, characterized in that: Application in wearable health monitoring clothing.

8. A self-powered smart garment for continuous monitoring of ECG and sweat composition, characterized in that: The device includes a garment body, and a sweat sensor, a fabric electrocardiogram sensor, a yarn battery, and a wireless data transmission module fixed to the garment body; the sweat sensor and the fabric electrocardiogram sensor are both electrically connected to the wireless data transmission module, transmitting the collected information to the wireless data transmission module; the yarn battery powers the wireless data transmission module; the sweat sensor is a flexible sweat sensor as described in any one of claims 1 to 5.

9. The self-powered smart garment for continuous monitoring of ECG and sweat composition according to claim 8, characterized in that: The garment itself has an elastic, tight-fitting structure that fits snugly against the skin when worn; The material of the garment body is one of polyester, spandex, nylon or a blend thereof; The sweat sensor, the fabric electrocardiogram sensor, the yarn battery, and the wireless data transmission module are all fixed to the garment body by heat pressing, sewing, or bonding. The fabric electrocardiogram sensor includes multiple silver-plated fabric electrocardiogram electrodes, which are distributed on the garment body. The silver-plated fabric electrocardiogram electrode includes a sponge pad, a copper foil electrode covering the outer surface of the sponge pad, a wire connected to the copper foil electrode, and a silver-plated fabric covering the copper foil electrode. The silver-plated fabric ECG electrode also includes an adhesive layer that is attached to the surface of the silver-plated fabric and can fix the silver-plated fabric ECG electrode to the garment body; The adhesive layer is a cloth-based adhesive tape.

10. The self-powered smart garment for continuous monitoring of ECG and sweat composition according to claim 8, characterized in that: The yarn battery is a yarn-shaped nickel battery, with nickel-plated @cobalt-nickel hydroxide yarn as the positive electrode and zinc-plated yarn as the negative electrode. The nickel-plated @cobalt-nickel hydroxide yarn is deposited on the surface of a double-strand silver-plated yarn by electrochemical deposition, and then converted into nickel-plated @cobalt-nickel hydroxide yarn by electrochemical deposition. The zinc-plated yarn is deposited on the surface of a double-strand silver-plated yarn by electrochemical deposition.

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