Conductive filament for smart wearable devices and preparation method thereof

Abstract

The present invention discloses a conductive filament for use in smart wearable devices and a preparation method thereof. This method, which belongs to the field of conductive materials technology, comprises pre-treating polyurethane filaments, immersing them in a dopamine hydrochloride solution to form a coating, then treating them in a silver ammonia solution to deposit a silver layer thereon, and finally electrochemically modifying them in an aqueous solution of a modified thiophene compound and polyethylene glycol to obtain the final conductive filament. Compared with existing technologies, this conductive filament exhibits excellent electrical conductivity, wear resistance, and corrosion resistance, making it suitable for long-term use in various environments, providing a high-performance conductive material for smart wearable devices.

Description

Technical Field

[0001] The present invention relates to the technical field of conductive materials, and in particular to a conductive filament used in smart wearable devices and a preparation method thereof. Background Art

[0002] With the rapid development of smart wearable devices, the demand for high-performance conductive materials is growing. These devices often require the integration of flexible, stretchable conductive fibers to achieve various functions such as biosignal monitoring, energy harvesting, and human-computer interaction. As a key component of smart textiles, the performance of conductive fibers directly affects the performance and reliability of wearable devices.

[0003] In existing technologies, conductive fibers are usually prepared by compounding conductive materials such as metal wire, carbon fiber or conductive polymer with textile fibers. However, these methods often have some limitations, such as the contradiction between conductive properties and mechanical flexibility, durability problems caused by insufficient interfacial bonding, and stability problems under complex deformation. Especially under repeated mechanical deformation and chemical corrosion environments, how to maintain the interfacial bonding between the conductive material and the fiber substrate, and how to achieve multi-site differentiated sensing of one-dimensional fibers, are major challenges facing the current smart wearable field.

[0004] In addition, smart wearable devices need to have good wear resistance and corrosion resistance in practical applications to adapt to various usage environments and conditions. Therefore, the development of a conductive fiber with excellent conductivity, high durability, good wear resistance and corrosion resistance is of great significance to promote the development of smart wearable devices.

[0005] Chinese invention patent CN111395002A discloses a method for preparing a textile electrode material and the textile electrode material. The method comprises: first, soaking a pretreated fabric in a dopamine hydrochloride solution to obtain a polydopamine-coated fabric; then soaking the polydopamine-coated fabric in a silver ammonia solution, and after a certain period of time, adding a glucose solution to obtain a silver-coated fabric; then electrochemically chlorinating the silver-coated fabric in a sodium chloride solution to form a silver-silver chloride composite-coated fabric; and finally, electrochemically modifying the silver-silver chloride composite-coated fabric in a conductive polymer monomer solution to obtain a silver-silver chloride-conductive polymer composite-coated fabric. The textile electrode material has a surface resistivity of 0.01 to 5 Ω, a polarization impedance of 10 to 1000 Ω in a 0.9% sodium chloride solution, an interface impedance with skin of 1 kΩ to 100 MΩ at 1 Hz, and a phase angle variation of 0 to 30° within a frequency range of 0.5 to 50 Hz. However, the wear resistance and corrosion resistance of the prepared textile electrode material still need to be improved, and cannot fully meet the material requirements of smart wearables. Summary of the Invention

[0006] To address these issues, the present invention provides a conductive filament for use in smart wearable devices and a method for preparing the same. This method utilizes a series of refined surface treatment and chemical modification steps to achieve conductive material coating and deposition on the surface of polyurethane filaments, as well as modification with a conductive polymer, thereby producing a conductive filament with excellent performance. This filament not only exhibits excellent electrical conductivity but also exhibits excellent wear and corrosion resistance, meeting the demand for high-performance conductive materials in smart wearable devices.

[0007] In order to achieve the above-mentioned object of the invention, the present invention adopts the following technical solutions:

[0008] A method for preparing conductive filaments for use in smart wearable devices is as follows:

[0009] Step 1: soaking the polyurethane filament in an ethanol aqueous solution, then taking out the filament and ultrasonically removing the oil on the surface in an acetone solution, then taking out and rinsing with water and drying to obtain a pretreated filament;

[0010] Step 2: Soaking the pretreated filament prepared in step 1 in a dopamine hydrochloride solution for 20 to 30 hours; during the soaking process, adding 5 to 15% dopamine hydrochloride solution of the total solid-liquid volume every 0.5 to 2 hours, and shaking to obtain a coated filament;

[0011] Step 3, soaking the coated filament obtained in step 2 in a silver ammonia solution for 30 to 50 minutes, with a bath ratio of 1:10 to 20, and adding 20 to 30 g / L ascorbic acid aqueous solution to the silver ammonia solution after the treatment, and then treating for another 30 to 50 minutes to obtain a deposited filament;

[0012] Step 4: The deposited filaments prepared in step 3 are washed and dried with water, and modified in a post-treatment solution by an electrochemical method with a bath ratio of 1:20 to 40. The post-treatment solution is an aqueous solution containing 4 to 6 g / L of a modified thiophene compound and 8 to 12 g / L of polyethylene glycol to obtain the final conductive filaments.

[0013] The polyurethane filaments are immersed in a 60-80 wt% ethanol aqueous solution for 2-4 hours, with a bath ratio of 1:5-15.

[0014] The filament is ultrasonically treated in an acetone solution for 5 to 15 minutes with an ultrasonic power of 200 to 400 W, a frequency of 20 to 60 kHz, and a bath ratio of 1:5 to 10.

[0015] The concentration of the dopamine hydrochloride solution is controlled at 30-50 g / L, and the soaking bath ratio is 1:15-25.

[0016] The oscillation frequency is 40 to 60 times per minute.

[0017] The preparation method of the silver ammonia solution is as follows: 20-40 g / L of silver nitrate solution is prepared, and 1-3 wt% of dilute ammonia water is added dropwise until the solution produces precipitation and becomes clear.

[0018] The treatment voltage of the electrochemical method in step 4 is 2.5 to 3.5 V, and the treatment time is 60 to 100 seconds.

[0019] The preparation method of the modified thiophene compound is as follows, in parts by weight:

[0020] After 1 to 1.4 parts of 2,5-dichloro-thiophene-3,4-dicarboxylic acid and 8 to 12 parts of dimethylformamide are uniformly mixed under a nitrogen atmosphere, 0.1 to 0.3 parts of diethyl carbonate are added, and mixing is continued for 10 to 20 minutes. Then, 0.3 to 0.5 parts of (3-aminopropyl) tris(trimethylsiloxy) silane and 0.3 to 0.5 parts of N-[3-[tri(octyloxy)silyl]propyl]ethylenediamine are simultaneously added dropwise to the mixed solution at a dropping rate of 1 to 3 mL / min. Stirring is continuously performed during the dropping process. After the dropping is completed, the mixed solution is heated to 90 to 100° C., treated for 2 to 4 hours, and then heated to 130 to 150° C., treated for 1 to 3 hours, and then the excess solvent is removed by rotary evaporation to obtain the modified thiophene compound.

[0021] In the method for preparing the conductive filament of the present invention, the functions of the various substances are as follows:

[0022] Polyurethane filaments are used as the substrate, and their good mechanical properties and flexibility make them ideal conductive fiber materials for smart wearable devices.

[0023] The ethanol aqueous solution is used in the pretreatment step to remove oil and other impurities on the surface of the polyurethane filaments, providing a clean surface for subsequent chemical modification.

[0024] Acetone solution is used during the ultrasonic process to further remove the oil on the surface of the filaments and enhance the surface activity of the filaments to facilitate subsequent chemical modification.

[0025] The dopamine hydrochloride solution is used in step 2. Dopamine is polymerized on the surface of the filament by soaking to form a film, which can provide good adhesion.

[0026] The silver ammonia solution is used in step 3 to form a silver deposition on the surface of the filament through the silver ammonia solution treatment, thereby enhancing the conductive performance of the filament.

[0027] Ascorbic acid aqueous solution is added to the silver ammonia solution as a reducing agent to promote the deposition of silver and improve the uniformity and stability of the conductive layer.

[0028] The modified thiophene compound is used in step 4 to form a conductive polymer film on the surface of the filament by an electrochemical method, thereby further improving the conductive performance and stability of the filament.

[0029] The polyethylene glycol in the post-treatment solution helps the modified thiophene compound to be evenly distributed on the surface of the filament.

[0030] (3-Aminopropyl)tris(trimethylsiloxy)silane is used as a silane coupling agent in the preparation of a modified thiophene compound to enhance the adhesion between the modified thiophene compound and a filament substrate.

[0031] N-[3-[Tri(octyloxy)silyl]propyl]ethylenediamine also acts as a silane coupling agent, used with (3-aminopropyl)tris(trimethylsiloxy)silane, to provide additional adhesion and stability.

[0032] Dimethylformamide is used as a solvent to mix and dissolve 2,5-dichloro-thiophene-3,4-dicarboxylic acid, thereby providing a uniform reaction environment for the synthesis of modified thiophene compounds.

[0033] Diethyl carbonate serves as a reaction accelerator to facilitate the reaction between the silane coupling agent and the thiophene compound.

[0034] The synergistic effect of these substances ensures that the surface of the substrate is effectively treated during the preparation of the conductive filaments, and the conductive layer is formed evenly and stably. The final conductive filaments have good electrical properties and mechanical stability, and are suitable for smart wearable devices.

[0035] Compared with the existing technology, it has the following beneficial effects:

[0036] 1) This invention significantly improves the conductivity of polyurethane filaments by coating them with a conductive material and modifying them with conductive polymers, such as modified thiophene compounds. These modified filaments can serve as key materials in smart wearable devices, transmitting electrical signals and energy.

[0037] 2) During the preparation process, the present invention uses electrochemical methods and a modified thiophene compound in the post-treatment solution for surface modification, enhancing the bonding between the conductive layer and the filament substrate, thereby improving the filament's wear and corrosion resistance. This enhanced stability allows the filament to maintain its conductive properties despite repeated stretching, friction, or chemical corrosion.

[0038] 3) Due to the inherent elasticity and flexibility of polyurethane, combined with the surface modification of modified thiophene compounds, the conductive filaments not only maintain their electrical conductivity but also possess excellent mechanical stretchability and flexibility. Such filaments can better adapt to human movement, provide a more comfortable wearing experience, and can be repeatedly washed without affecting their performance. DETAILED DESCRIPTION

[0039] Main sources of substances:

[0040] Polyurethane filament, porosity: 36F, denier: 140D, white.

[0041] The remaining raw materials in the examples and comparative examples of the present invention are all commercially available products.

[0042] The design concept of this invention is to prepare polyurethane-based conductive filaments with excellent electrical conductivity, wear resistance, and corrosion resistance through a series of refined surface treatment and chemical modification steps to meet the needs of smart wearable devices for high-performance conductive materials. Specifically, the surface oil of the filaments is removed through pretreatment, and the coating and deposition treatment are carried out using dopamine hydrochloride solution and silver ammonia solution. The surface is modified by electrochemical methods combined with modified thiophene compounds and polyethylene glycol, thereby forming a stable conductive layer on the surface of the polyurethane filaments. It maintains good mechanical properties and has excellent electrical properties, making it suitable for long-term use in various environments.

[0043] Example 1

[0044] A method for preparing conductive filaments for use in smart wearable devices is as follows:

[0045] Step 1, soaking the polyurethane filament in a 70wt% ethanol aqueous solution for 3 hours at a bath ratio of 1:10, then taking out the filament and ultrasonically treating it in an acetone solution for 10 minutes at an ultrasonic power of 300W, a frequency of 40kHz, and a bath ratio of 1:8 to remove the oil on the surface, taking it out and rinsing it with water and drying it to obtain a pretreated filament;

[0046] Step 2, soaking the pretreated filament prepared in step 1 in a dopamine hydrochloride solution, wherein the concentration of the dopamine hydrochloride solution is controlled at 40 g / L, the bath ratio is 1:20, and the soaking time is 24 hours; during the soaking process, adding 10% of the total solid-liquid volume of the dopamine hydrochloride solution every hour, and shaking, the oscillation frequency is 50 times / minute, to obtain a coated filament;

[0047] Step 3, soaking the coated filament obtained in step 2 in a silver ammonia solution for 40 minutes, with a bath ratio of 1:15. The preparation method of the silver ammonia solution is as follows: preparing a 30g / L silver nitrate solution and adding 2wt% dilute ammonia water dropwise until the solution produces precipitation and becomes clear; after the treatment is completed, adding 25g / L ascorbic acid aqueous solution to the silver ammonia solution and treating for another 40 minutes to obtain a deposited filament;

[0048] Step 4: The deposited filaments prepared in step 3 are washed and dried with water, and modified in a post-treatment solution by an electrochemical method with a bath ratio of 1:30. The post-treatment solution is an aqueous solution containing 5 g / L of a modified thiophene compound and 10 g / L of polyethylene glycol. The treatment voltage is 3 V and the time is 80 s to obtain the final conductive filaments.

[0049] The preparation method of the modified thiophene compound is as follows:

[0050] 1.2 kg of 2,5-dichloro-thiophene-3,4-dicarboxylic acid and 10 kg of dimethylformamide were mixed uniformly under a nitrogen atmosphere, and then 0.2 kg of diethyl carbonate was added. After continuing to mix for 15 minutes, 0.8 kg of (3-aminopropyl) tris(trimethylsiloxy)silane was added dropwise to the mixed solution at a dropping rate of 2 mL / min. The mixture was stirred continuously during the dropping process. After the dropping was completed, the mixed solution was heated to 95°C and treated for 3 hours. Then, the temperature was raised to 140°C and treated for 2 hours. The excess solvent was removed by rotary evaporation to obtain a modified thiophene compound.

[0051] Example 2

[0052] A method for preparing a conductive filament for use in a smart wearable device is substantially the same as that in Example 1, with the only difference being the method for preparing the modified thiophene compound.

[0053] The preparation method of the modified thiophene compound is as follows:

[0054] 1.2 kg of 2,5-dichloro-thiophene-3,4-dicarboxylic acid and 10 kg of dimethylformamide were mixed evenly under a nitrogen atmosphere, and then 0.2 kg of diethyl carbonate was added. After continuing to mix for 15 minutes, 0.8 kg of M-aminophenyltrimethoxysilane was added dropwise to the mixed solution at a dropping rate of 2 mL / min. Stirring was continued during the dropping process. After the addition was completed, the mixed solution was heated to 95°C and treated for 3 hours. Then, the temperature was raised to 140°C and treated for 2 hours. The excess solvent was removed by rotary evaporation to obtain a modified thiophene compound.

[0055] Example 3

[0056] A method for preparing a conductive filament for use in a smart wearable device is substantially the same as that in Example 1, with the only difference being the method for preparing the modified thiophene compound.

[0057] The preparation method of the modified thiophene compound is as follows:

[0058] 1.2 kg of 2,5-dichloro-thiophene-3,4-dicarboxylic acid and 10 kg of dimethylformamide were mixed uniformly under a nitrogen atmosphere, and 0.2 kg of diethyl carbonate was added. After continuing to mix for 15 minutes, 0.8 kg of N-(2-aminoethyl)-3-aminopropyltrimethoxysilane was added dropwise to the mixed solution at a dropping rate of 2 mL / min. The mixture was stirred continuously during the dropping process. After the addition was completed, the mixed solution was heated to 95°C and treated for 3 hours, then heated to 140°C and treated for 2 hours. The excess solvent was removed by rotary evaporation to obtain a modified thiophene compound.

[0059] Example 4

[0060] A method for preparing a conductive filament for use in a smart wearable device is substantially the same as that in Example 1, with the only difference being the method for preparing the modified thiophene compound.

[0061] The preparation method of the modified thiophene compound is as follows:

[0062] 1.2 kg of 2,5-dichloro-thiophene-3,4-dicarboxylic acid and 10 kg of dimethylformamide were mixed uniformly under a nitrogen atmosphere, and then 0.2 kg of diethyl carbonate was added. After continuing to mix for 15 minutes, 0.8 kg of 4-(triisopropylsilyloxy)aniline was added dropwise to the mixed solution at a dropping rate of 2 mL / min. The mixture was stirred continuously during the dropping process. After the dropping was completed, the mixed solution was heated to 95° C. and treated for 3 hours. Then, the temperature was raised to 140° C. and treated for 2 hours. The excess solvent was removed by rotary evaporation to obtain a modified thiophene compound.

[0063] Example 5

[0064] A method for preparing a conductive filament for use in a smart wearable device is substantially the same as that in Example 1, with the only difference being the method for preparing the modified thiophene compound.

[0065] The preparation method of the modified thiophene compound is as follows:

[0066] 1.2 kg of 2,5-dichloro-thiophene-3,4-dicarboxylic acid and 10 kg of dimethylformamide were mixed uniformly under a nitrogen atmosphere, and 0.2 kg of diethyl carbonate was added. After continuing to mix for 15 minutes, 0.8 kg of 3-aminopropylbis(trimethylsilyloxy)methylsilane was added dropwise to the mixed solution at a dropping rate of 2 mL / min. Stirring was continued during the addition. After the addition was completed, the mixed solution was heated to 95°C and treated for 3 hours. Then, the temperature was raised to 140°C and treated for 2 hours. The excess solvent was removed by rotary evaporation to obtain a modified thiophene compound.

[0067] Example 6

[0068] A method for preparing a conductive filament for use in a smart wearable device is substantially the same as that in Example 1, with the only difference being the method for preparing the modified thiophene compound.

[0069] The preparation method of the modified thiophene compound is as follows:

[0070] 1.2 kg of 2,5-dichloro-thiophene-3,4-dicarboxylic acid and 10 kg of dimethylformamide were mixed uniformly under a nitrogen atmosphere, and then 0.2 kg of diethyl carbonate was added. After continuing to mix for 15 minutes, 0.8 kg of N-[3-[tri(octyloxy)silyl]propyl]ethylenediamine was added dropwise to the mixed solution at a dropping rate of 2 mL / min. The mixture was stirred continuously during the dropping process. After the addition was completed, the mixed solution was heated to 95° C. and treated for 3 hours. Then, the temperature was raised to 140° C. and treated for 2 hours. The excess solvent was removed by rotary evaporation to obtain a modified thiophene compound.

[0071] Example 7

[0072] A method for preparing a conductive filament for use in a smart wearable device is substantially the same as that in Example 1, with the only difference being the method for preparing the modified thiophene compound.

[0073] The preparation method of the modified thiophene compound is as follows:

[0074] 1.2 kg of 2,5-dichloro-thiophene-3,4-dicarboxylic acid and 10 kg of dimethylformamide were mixed uniformly under a nitrogen atmosphere, and 0.2 kg of diethyl carbonate was added. After continuing to mix for 15 minutes, 0.4 kg of (3-aminopropyl) tris(trimethylsiloxy) silane and 0.4 kg of N-[3-[tri(octyloxy)silyl]propyl]ethylenediamine were added dropwise to the mixed solution at the same time. The addition rate was 2 mL / min, and the mixture was stirred continuously during the addition. After the addition was completed, the mixed solution was heated to 95 ° C. and treated for 3 hours. It was then heated to 140 ° C. and continued to treat for 2 hours. The excess solvent was removed by rotary evaporation to obtain a modified thiophene compound.

[0075] Comparative Example 1

[0076] A method for preparing a conductive filament for use in a smart wearable device is substantially the same as that in Example 1, with the only difference being the method for preparing the modified thiophene compound.

[0077] The preparation method of the modified thiophene compound is as follows:

[0078] 1.2 kg of 3,4-thiophenedicarboxylic acid and 10 kg of dimethylformamide were mixed uniformly under a nitrogen atmosphere, and then 0.2 kg of diethyl carbonate was added. After continuing to mix for 15 minutes, 0.4 kg of (3-aminopropyl) tris(trimethylsiloxy) silane and 0.4 kg of N-[3-[tri(octyloxy)silyl]propyl]ethylenediamine were added dropwise to the mixed solution at a dropping rate of 2 mL / min. The mixture was stirred continuously during the addition. After the addition was completed, the mixed solution was heated to 95° C. and treated for 3 hours. Then, the temperature was raised to 140° C. and treated for 2 hours. The excess solvent was removed by rotary evaporation to obtain a modified thiophene compound.

[0079] Comparative Example 2

[0080] A method for preparing conductive filaments for use in smart wearable devices is as follows:

[0081] Step 1, soaking the polyurethane filament in a 70wt% ethanol aqueous solution for 3 hours at a bath ratio of 1:10, then taking out the filament and ultrasonically treating it in an acetone solution for 10 minutes at an ultrasonic power of 300W, a frequency of 40kHz, and a bath ratio of 1:8 to remove the oil on the surface, taking it out and rinsing it with water and drying it to obtain a pretreated filament;

[0082] Step 2, soaking the pretreated filament prepared in step 1 in a dopamine hydrochloride solution, wherein the concentration of the dopamine hydrochloride solution is controlled at 40 g / L, the bath ratio is 1:20, and the soaking time is 24 hours; during the soaking process, adding 10% of the total solid-liquid volume of the dopamine hydrochloride solution every hour, and shaking, the oscillation frequency is 50 times / minute, to obtain a coated filament;

[0083] Step 3, soaking the coated filament obtained in step 2 in a silver ammonia solution for 40 minutes, with a bath ratio of 1:15. The preparation method of the silver ammonia solution is as follows: preparing a 30g / L silver nitrate solution and adding 2wt% dilute ammonia water dropwise until the solution produces precipitation and becomes clear; after the treatment is completed, adding 25g / L ascorbic acid aqueous solution to the silver ammonia solution and treating for another 40 minutes to obtain a deposited filament;

[0084] Step 4: The deposited filaments prepared in step 3 are washed and dried with water, and modified in a post-treatment solution by an electrochemical method with a bath ratio of 1:30. The post-treatment solution is an aqueous solution containing 5 g / L of 2,5-dichloro-thiophene-3,4-dicarboxylic acid and 10 g / L of polyethylene glycol. The treatment voltage is 3 V and the time is 80 s to obtain the final conductive filaments.

[0085] Comparative Example 3

[0086] A method for preparing conductive filaments for use in smart wearable devices is as follows:

[0087] Step 1, soaking the polyurethane filament in a 70wt% ethanol aqueous solution for 3 hours at a bath ratio of 1:10, then taking out the filament and ultrasonically treating it in an acetone solution for 10 minutes at an ultrasonic power of 300W, a frequency of 40kHz, and a bath ratio of 1:8 to remove the oil on the surface, taking it out and rinsing it with water and drying it to obtain a pretreated filament;

[0088] Step 2, soaking the pretreated filament prepared in step 1 in a dopamine hydrochloride solution, wherein the concentration of the dopamine hydrochloride solution is controlled at 40 g / L, the bath ratio is 1:20, and the soaking time is 24 hours; during the soaking process, adding 10% of the total solid-liquid volume of the dopamine hydrochloride solution every hour, and shaking, the oscillation frequency is 50 times / minute, to obtain a coated filament;

[0089] Step 3, soaking the coated filament obtained in step 2 in a silver ammonia solution for 40 minutes, with a bath ratio of 1:15. The preparation method of the silver ammonia solution is as follows: preparing a 30g / L silver nitrate solution and adding 2wt% dilute ammonia water dropwise until the solution produces precipitation and becomes clear; after the treatment is completed, adding 25g / L ascorbic acid aqueous solution to the silver ammonia solution and treating for another 40 minutes to obtain a deposited filament;

[0090] Step 4: The deposited filaments prepared in step 3 are washed and dried with water, and modified in a post-treatment solution by an electrochemical method with a bath ratio of 1:30. The post-treatment solution is an aqueous solution containing 5 g / L of 3,4-thiophenedicarboxylic acid and 10 g / L of polyethylene glycol. The treatment voltage is 3 V and the time is 80 s to obtain the final conductive filaments.

[0091] Comparative Example 4

[0092] A method for preparing conductive filaments for use in smart wearable devices is as follows:

[0093] Step 1, soaking the polyurethane filament in a 70wt% ethanol aqueous solution for 3 hours at a bath ratio of 1:10, then taking out the filament and ultrasonically treating it in an acetone solution for 10 minutes at an ultrasonic power of 300W, a frequency of 40kHz, and a bath ratio of 1:8 to remove the oil on the surface, taking it out and rinsing it with water and drying it to obtain a pretreated filament;

[0094] Step 2, soaking the pretreated filament prepared in step 1 in a dopamine hydrochloride solution, wherein the concentration of the dopamine hydrochloride solution is controlled at 40 g / L, the bath ratio is 1:20, and the soaking time is 24 hours; during the soaking process, adding 10% of the total solid-liquid volume of the dopamine hydrochloride solution every hour, and shaking, the oscillation frequency is 50 times / minute, to obtain a coated filament;

[0095] Step 3, soaking the coated filament obtained in step 2 in a silver ammonia solution for 40 minutes, with a bath ratio of 1:15. The preparation method of the silver ammonia solution is as follows: preparing a 30g / L silver nitrate solution and adding 2wt% dilute ammonia water dropwise until the solution produces precipitation and becomes clear; after the treatment is completed, adding 25g / L ascorbic acid aqueous solution to the silver ammonia solution and treating for another 40 minutes to obtain a deposited filament;

[0096] Step 4: Wash and dry the deposited filaments prepared in step 3 with water to obtain the final conductive filaments.

[0097] Test Example 1

[0098] Wear resistance test

[0099] The conductive filaments prepared in this example and the comparative example were tested for electrical conductivity, using resistivity as the reference in GB / T 15738-2008, "Test Method for Electrical Resistivity of Conductive and Antistatic Fiber-Reinforced Plastics." The conductive filaments were then subjected to abrasion and fracture tests using a dedicated wear tester. The test conditions were: a speed of 440 r / min and a tension of 14 N. After 200 cycles of friction, the conductive properties were retested. The test results are shown in Table 1.

[0100] Table 1

[0101]

[0102]

[0103] Test Example 2

[0104] Corrosion resistance test

[0105] The conductive filaments prepared in this embodiment and the comparative example were immersed in 3.5% by mass NaCl solution, 10% by mass HCl solution, and 10% by mass NaOH solution, respectively, with a bath ratio of 1:20, and soaked at (25±1)°C for 3 days. After washing with clean water, the conductive properties were tested with reference to GB / T 15738-2008 "Test method for resistivity of conductive and antistatic fiber-reinforced plastics".

[0106] The test results are shown in Table 2.

[0107] Table 2

[0108]

[0109] It can be seen from the data in Tables 1 and 2 that the conductive filament prepared in Example 7 has the best wear resistance and corrosion resistance.

[0110] The conductive filament prepared by (3-aminopropyl) tris(trimethylsiloxy) silane in Example 1 has better wear resistance and corrosion resistance than the different silanes used in other embodiments. This is mainly due to the presence of multiple trimethylsiloxy groups in the molecular structure of (3-aminopropyl) tris(trimethylsiloxy) silane, which can form strong chemical bonds with the hydroxyl groups or other active groups on the surface of the filament, thereby enhancing the bonding force between the conductive layer and the filament substrate. In addition, the trimethylsiloxy group can also provide an additional hydrophobic protective layer, reducing the erosion of the conductive layer by moisture and corrosive substances in the environment. This dual protection mechanism makes the conductive filament prepared by (3-aminopropyl) tris(trimethylsiloxy) silane more excellent in wear resistance and corrosion resistance. When this modified filament is used in intelligent wearable devices, it can provide more lasting conductivity and better durability, meeting the needs of wearable devices for long-term use in various environments.

[0111] When comparing Example 1 and Comparative Example 1, it can be found that the main difference between the two is that the raw materials of the modified thiophene compound are different. Example 1 uses 2,5-dichloro-thiophene-3,4-dicarboxylic acid, while Comparative Example 1 uses 3,4-thiophenedicarboxylic acid. Compared with 3,4-thiophenedicarboxylic acid, the introduction of chlorine atoms in the molecular structure of 2,5-dichloro-thiophene-3,4-dicarboxylic acid increases the polarity of the molecule, which helps to improve the compatibility with the polyurethane filament substrate, thereby enhancing the adhesion of the modified thiophene compound to the surface of the filament. This stronger adhesion makes the conductive layer more stable and not easily removed in a wear or corrosive environment, thus showing better wear resistance and corrosion resistance. In addition, the presence of chlorine atoms may also help to improve the chemical stability of the conductive layer, because chlorine atoms can form chemical bonds with (3-aminopropyl) tris(trimethylsiloxy) silane to resist erosion by corrosive media. This structural stability further improves the performance of the conductive filament in harsh environments.

[0112] In Example 7, (3-aminopropyl) tris(trimethylsiloxy) silane is compounded with N-[3-[tri(octyloxy) silyl] propyl] ethylenediamine, which can significantly improve the wear resistance and corrosion resistance of the conductive filaments compared to using a silane alone. (3-aminopropyl) tris(trimethylsiloxy) silane can form a stable chemical bond with the surface of the filament, and the long-chain structure in N-[3-[tri(octyloxy) silyl] propyl] ethylenediamine provides better compatibility and dispersibility, and this compounding is used to enhance the adhesion between the modified thiophene compound and the filament substrate. A more complex network structure is formed on the surface of the filament, which not only enhances the combination between the conductive layer and the substrate, but also improves the stability and durability of the conductive layer itself.

[0113] The purpose of post-processing the deposited filaments by electrochemical methods in step 4 of the present invention is to further improve the conductivity and stability of the filaments. In this step, an aqueous solution containing a modified thiothiophene compound and polyethylene glycol is used as a post-processing solution to form a uniform and highly conductive coating on the surface of the filaments. The modified thiophene compound, as a conductive material, provides additional electron transport channels, enhancing the conductivity of the filaments. This step is crucial to ensuring the long-term and stable function of the filaments in smart wearable devices.

Claims

1. A method for preparing a conductive filament for use in smart wearable devices, characterized in that: Here’s how: Step 1: soaking the polyurethane filament in an ethanol aqueous solution, then taking out the filament and ultrasonically removing the oil on the surface in an acetone solution, then taking out and rinsing with water and drying to obtain a pretreated filament; Step 2: Soaking the pretreated filament prepared in step 1 in a dopamine hydrochloride solution for 20 to 30 hours; during the soaking process, adding 5 to 15% dopamine hydrochloride solution of the total solid-liquid volume every 0.5 to 2 hours, and shaking to obtain a coated filament; Step 3, soaking the coated filament obtained in step 2 in a silver ammonia solution for 30 to 50 minutes, with a bath ratio of 1:10 to 20, and adding 20 to 30 g / L ascorbic acid aqueous solution to the silver ammonia solution after the treatment, and then treating for another 30 to 50 minutes to obtain a deposited filament; Step 4: The deposited filaments prepared in step 3 are washed with water and dried, and then modified in a post-treatment solution by an electrochemical method at a bath ratio of 1:20-40. The post-treatment solution is an aqueous solution containing 4-6 g / L of a modified thiophene compound and 8-12 g / L of polyethylene glycol to obtain the final conductive filaments. The preparation method of the modified thiophene compound is as follows, in parts by weight: After 1-1.4 parts of 2,5-dichloro-thiophene-3,4-dicarboxylic acid and 8-12 parts of dimethylformamide are uniformly mixed under a nitrogen atmosphere, 0.1-0.3 parts of diethyl carbonate are added, and mixing is continued for 10-20 minutes. Then, 0.3-0.5 parts of (3-aminopropyl)tris(trimethylsiloxy)silane and 0.3-0.5 parts of N-[3-[tri(octyloxy)silyl]propyl]ethylenediamine are simultaneously added dropwise to the mixed solution at a dropping rate of 1-3 mL / min. Stirring is continued during the addition process. After the addition is completed, the mixed solution is heated to 90-100° C., treated for 2-4 hours, and then heated to 130-150° C., and treated for 1-3 hours. The excess solvent is removed by rotary evaporation to obtain the modified thiophene compound.

2. The method for preparing a conductive filament for use in a smart wearable device according to claim 1, wherein: The polyurethane filaments are immersed in a 60-80 wt% ethanol aqueous solution for 2-4 hours, with a bath ratio of 1:5-15.

3. The method for preparing a conductive filament for use in a smart wearable device according to claim 1, wherein: The filament is ultrasonically treated in an acetone solution for 5 to 15 minutes with an ultrasonic power of 200 to 400 W, a frequency of 20 to 60 kHz, and a bath ratio of 1:5 to 10.

4. The method for preparing a conductive filament for use in a smart wearable device according to claim 1, wherein: The concentration of the dopamine hydrochloride solution is controlled at 30-50 g / L, and the soaking bath ratio is 1:15-25.

5. The method for preparing a conductive filament for use in a smart wearable device according to claim 1, wherein: The oscillation frequency is 40 to 60 times per minute.

6. The method for preparing a conductive filament for use in a smart wearable device according to claim 1, wherein: The silver ammonia solution is prepared by preparing a 20-40 g / L silver nitrate solution and adding 1-3 wt % dilute ammonia water dropwise until the solution produces precipitation and becomes clear.

7. The method for preparing a conductive filament for use in a smart wearable device according to claim 1, wherein: The treatment voltage of the electrochemical method in step 4 is 2.5-3.5 V, and the treatment time is 60-100 s.

8. A conductive filament used in smart wearable devices, characterized in that: Prepared by the preparation method according to any one of claims 1 to 7.

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