A moisture power generation covering yarn and its preparation method and application

Abstract

The application relates to the technical field of spinning, and discloses a moisture power generation core-spun yarn and a preparation method and application thereof. The core-spun yarn has a three-layer sheath-core structure, the core layer is an inner electrode selected from silver-plated filaments, metal wires or carbon fibers, the middle layer is a power generation layer selected from moisture-absorbing nanofiber membranes, and the sheath layer is an outer electrode selected from silver-plated filaments. In the preparation, a moisture-absorbing nanofiber strip is prepared through electrospinning, is coated onto the surface of the inner electrode through a coating machine to form a power generation layer, and then the outer electrode is wrapped on the surface of the power generation layer to obtain a moisture power generation yarn. In the application, the nanofiber membrane is used as the power generation layer, the specific surface area of the power generation layer is improved, the moisture absorption performance of the power generation layer is improved, the spiral pitch of the outer electrode is regulated, the contact area between the power generation layer and moisture is controlled, and the maximum structure design of the moisture power generation power is realized. Finally, the moisture power generation core-spun yarn with stable electrode medium and high moisture-absorbing power generation power is obtained.

Description

Technical Field

[0001] This application relates to the field of spinning technology, specifically to a moisture-generating core-spun yarn, its preparation method, and its application. Background Technology

[0002] Moisture generators (MEGs) are an emerging green energy harvesting method that utilizes the energy from water evaporation or moisture in the atmosphere to generate electricity. Moisture generators directly power miniature, low-power electronic devices using ambient moisture, eliminating the need for additional energy storage. They offer advantages such as lightweight design, environmental friendliness, and simple structure, making them commonly used in wearable devices and other fields. Moisture generation achieves direct energy conversion from moisture to electricity through the interaction between materials and ambient moisture. Essentially, it utilizes the charge separation and directional migration induced by moisture to form a closed-loop current. Typical moisture generator mechanisms include ion migration power generation and charge separation power generation. When certain materials come into contact with moisture, the water in the moisture is adsorbed by the hydrophilic groups in the material and dissolved into a conductive medium containing ions. Due to the humidity gradient across the device, ions migrate directionally driven by the concentration difference. By placing electrodes at both ends of the device to collect the migrated charges, a continuous ion flow is formed, which in turn generates current in the external circuit. Another type of material has a special surface electronic structure. After adsorbing moisture, water molecules interact with the material surface, causing charge separation on the material surface. Guided by the humidity gradient or the material's microstructure, the separated charges move in a specific direction and are drawn out through electrodes to form an electric current.

[0003] Based on the principle of moisture power generation, many moisture power generation devices with different structures have emerged, such as thin-film moisture power generation devices, block moisture power generation devices, and yarn-based or fiber-based moisture power generation devices. Compared with thin-film and block moisture power generation devices, yarn-based moisture power generation devices have advantages such as flexibility, good breathability, and stable mechanical properties. Yarn-based moisture power generation devices meet the core requirements of flexible wearable energy, solving the shortcomings of traditional moisture power generation devices in terms of flexibility, integration, and comfort, and providing an ideal technical path for achieving long-term autonomous power supply for wearable electronic devices, IoT sensors, etc. Current research on yarn-based moisture power generation devices mainly focuses on improving the electrical output performance through structural design or material optimization. Chinese invention patent application CN119602630A discloses a core-skin structure moisture power generation device and its preparation method. The device includes a core layer, a skin layer, and a conductive metal wire wound around the skin layer. The core layer and skin layer are simultaneously extruded by coaxial spinning to obtain core-skin structure fibers. Then, the conductive metal wire is wound around the surface of the core-skin fiber to obtain the core-skin structure moisture power generation device. The skin layer of the device is made of polyvinyl alcohol, and the core layer is made of thermoplastic polyurethane containing conductive filler. By absorbing moisture through the skin layer, oxygen-containing functional groups are dissociated to generate a large number of mobile charged ions, forming an ion concentration gradient. Subsequently, these ions migrate directionally along the ion concentration gradient, resulting in a potential difference between the two electrodes, thereby inducing voltage output.

[0004] However, the outer electrodes of existing yarn-based sensors are generally composed of conductive coatings, which are prone to detachment and affect the hygroscopicity of the power generation layer. Therefore, this application employs a structural design that uses silver-plated filaments wrapped around the surface of the power generation layer to form external electrodes with adjustable spacing. By controlling the spacing of these external electrodes, the directional control of water molecules entering the core nanofibers can be achieved, improving the yarn's hygroscopic performance and optimizing moisture-generated power efficiency. This simultaneously solves the problems of easy detachment of the conductive coating and poor moisture-generated power performance. Summary of the Invention

[0005] To address the shortcomings of existing technologies, the primary objective of this application is to provide a moisture-generating core-spun yarn, its preparation method, and its applications. This application utilizes conductive filaments as the inner electrode of the core layer, moisture-absorbing nanofibers as the power-generating layer, and silver-plated filaments as the outer electrode of the sheath layer, forming a three-layer core-spun yarn. Using silver-plated filaments as the outer electrode ensures good conductivity, while the structure of the outer electrode retains porous channels that allow water molecules to enter and interact with the core layer, effectively improving the contact efficiency between the yarn and moisture. Using a moisture-absorbing nanofiber membrane as the power-generating layer, its nanostructure possesses an ultra-large specific surface area, effectively increasing moisture absorption performance. It is precisely due to the combined effect of the power-generating layer and the outer electrode structure that the moisture-absorbing power-generating yarn exhibits high moisture-absorbing power generation and a stable electrode medium.

[0006] To achieve the above objectives, this application provides the following technical solution:

[0007] In a first aspect, this application provides a moisture-generating core-spun yarn, wherein the core-spun yarn is composed of an inner electrode, a power-generating layer, and an outer electrode to form a three-layer core-skin structure; wherein the inner electrode is located in the core layer, the power-generating layer is located in the middle layer, and the outer electrode is located in the skin layer;

[0008] The internal electrode comprises any one of silver-plated filament, metal wire, or carbon fiber.

[0009] The power generation layer is a moisture-absorbing nanofiber membrane;

[0010] The external electrode is a silver-plated filament.

[0011] It should be noted that the moisture-generating cored yarn prepared in this application relies on a hygroscopic nanofiber membrane in the power generation layer to capture moisture from the air. The outer side of the power generation layer has a larger contact area with moisture and can also prevent some moisture from diffusing inward, resulting in more water molecules being adsorbed by the outer fibers and relatively fewer water molecules being adsorbed by the inner fibers. Water molecules can cause the inner and outer materials to dissociate into positive and negative ions with different concentrations, thereby forming an ion concentration gradient; driven by the ion concentration difference, charges undergo directional migration, thereby forming an electric current and realizing the moisture-generating function. The output power of moisture-generating power is closely related to the hygroscopic performance of the power generation layer; the stronger the hygroscopic capacity of the material, the higher the power generation is usually. To this end, this application uses a nanofiber membrane in its structure to significantly increase the specific surface area and enhance the hygroscopic capacity of the power generation layer, thereby improving the power generation; in terms of material selection, highly hygroscopic polymers such as polyvinyl alcohol (PVA) and polyethylene oxide (PEO) are preferred, and electrolytes can be introduced into the system to further improve the moisture-generating performance.

[0012] Preferably, the core layer thickness is 10~100μm, the intermediate layer thickness is 50~300μm, and the skin layer thickness is 80~500μm.

[0013] Preferably, the linear density of the silver-plated filament is 15~35 tex.

[0014] Secondly, this application provides a method for preparing a moisture-generating core-spun yarn, comprising the following steps:

[0015] Add the moisture-absorbing material to the solvent, stir magnetically at 50~60℃ and 500~1000rpm for 5~8h, and degas under vacuum to obtain the moisture-absorbing material spinning solution.

[0016] The hygroscopic material spinning solution is sprayed from the spinning nozzle using an electrospinning device. After drying and curing, it forms a hygroscopic nanofiber membrane on the receiving device. The hygroscopic nanofiber membrane is then cut and bonded to obtain hygroscopic nanofiber strips with a width of 2-5 mm.

[0017] Using the inner electrode as the core wire, a moisture-absorbing nanofiber strip is spirally wrapped onto the surface of the core wire using a coating machine to obtain a composite core wire; then, using the coating machine, an outer electrode is spirally wrapped onto the surface of the composite core wire to obtain a moisture-generating core-spun yarn.

[0018] It should be noted that by preparing a moisture-absorbing nanofiber membrane using electrospinning equipment and then processing the moisture-absorbing nanofibers into strips to coat the surface of the inner electrode, the coating effect of the moisture-absorbing nanofiber membrane can be more effectively controlled, achieving complete coating of the inner electrode. This avoids the problem of incomplete coating that may occur with direct electrospinning coating, which could lead to a short circuit between the inner and outer electrodes.

[0019] Preferably, the moisture-absorbing material includes polyvinyl alcohol (PVA), polyethylene oxide (PEO), and sodium alginate.

[0020] Preferably, the solvent is deionized water.

[0021] Preferably, the mass ratio of the moisture-absorbing material to the solvent is (5~10):(45~90).

[0022] Preferably, the electrospinning parameters are: voltage 15~18kV, distance between nozzle and receiving device 15~20cm, and spinning solution flow rate 0.5~0.8mL / h.

[0023] Preferably, the spinning parameters of the covered yarn machine are: core yarn feeding speed 1~10m / min, core yarn tension 0.1~10cN, moisture-absorbing nanofiber strip twist 300~600T / m; composite core yarn feeding speed 2~10m / min, composite core yarn tension 0.1~10cN, and external electrode covering twist 100~1000T / m.

[0024] It should be noted that when using a covering yarn machine to cover the external electrode onto the power generation layer, in order to further increase the contact area between the power generation layer and moisture, the spinning parameters of the covering yarn machine can be adjusted to increase the covering pitch of the external electrode, so that more power generation layer material is exposed to the humid environment, thereby improving the moisture absorption of the yarn.

[0025] Thirdly, this application provides an application of a moisture-generating core-spun yarn, which can be used in smart wearable devices and self-powered power supplies.

[0026] The beneficial effects of this application are:

[0027] This application uses a hygroscopic material to construct a nanofiber membrane, which is then processed into strips and coated onto the surface of the inner electrode using a coating spinning technique to form a power generation layer. This method can adjust the coating spinning parameters to ensure that the nanofiber membrane completely covers the inner electrode, avoiding short circuits between the inner and outer electrodes caused by incomplete coating. In addition, the nanostructured power generation layer has a larger specific surface area, which enhances the hygroscopic properties of the power generation layer, thereby improving the power generation capacity.

[0028] The outer electrode uses silver-plated filaments, which protect the core structure from wear while retaining porous channels for water molecules to enter and interact with the core. The helical spacing of the silver-plated filaments during coating is a key parameter affecting the performance of wet gas power generation. If the spacing is too large, the exposed area of ​​the core increases, making it susceptible to mechanical wear and material failure. Simultaneously, the internal nanofibers absorb moisture, weakening the ion concentration gradient and causing a drop in output voltage. Conversely, if the spacing is too small, water molecules have difficulty entering the core, limiting the moisture absorption and ionization process of the nanofibers, also resulting in reduced output performance. This application, by controlling the process parameters of the coating machine, can precisely adjust the helical spacing of the outer silver-plated filament electrode, thereby changing the number and distribution of surface helical gaps. This allows for directional control of water molecule entry into the core nanofibers, optimizing wet gas power generation efficiency and improving power generation performance. Attached Figure Description

[0029] To more clearly illustrate the technical solutions of the embodiments of this application, the drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0030] Figure 1 A flowchart illustrating the preparation method of the first type of moisture-generating core-spun yarn provided in this application.

[0031] Figure 2 The image shows the morphology of the PVA nanofiber membrane obtained in step 2 of Example 1.

[0032] Figure 3 This is a schematic diagram of a voltage and current output testing device for moisture-generating core-spun yarn.

[0033] Figure 4 The voltage output curves are for the moisture-generating core-spun yarns prepared by the methods described in Examples 1-3 and Comparative Example 1.

[0034] Figure 5 The current output curves are for the moisture-generating core-spun yarns prepared by the methods described in Examples 1-3 and Comparative Example 1.

[0035] Figure 6The images show the appearance of the moisture-generating core-spun yarn prepared by the method described in Examples 1-3.

[0036] Figure 7 The voltage output of the moisture-generating core-spun yarn prepared by the method described in Example 2 and Comparative Example 3 is compared. Detailed Implementation

[0037] To make the above-mentioned objectives, features and advantages of this application more apparent and understandable, the specific embodiments of this application will be described in detail below with reference to the accompanying drawings.

[0038] Many specific details are set forth in the following description in order to provide a full understanding of this application. However, this application may also be implemented in other ways different from those described herein. Those skilled in the art can make similar extensions without departing from the spirit of this application. Therefore, this application is not limited to the specific embodiments disclosed below.

[0039] The following specific embodiments further illustrate this point:

[0040] Example 1

[0041] like Figure 1 As shown, this embodiment provides a method for preparing moisture-generating core-spun yarn:

[0042] 1. PVA is added to deionized water and magnetically stirred at 500 rpm for 5 hours at 50°C. Vacuum degassing is then performed to obtain the PVA spinning solution. The mass ratio of PVA to deionized water is 5:45.

[0043] 2. Set the electrospinning machine voltage to 15kV, the distance between the spinning nozzle and the receiving device to 15cm, and the spinning solution flow rate to 0.5mL / h. Then, spray the PVA spinning solution from the spinning nozzle, and after drying and curing, form a PVA nanofiber membrane on the receiving device.

[0044] 3. Cut the PVA nanofiber membrane into strips 2 mm wide and bond them together to obtain PVA nanofiber strips;

[0045] 4. Feed the silver-plated nylon filament onto the covering yarn machine, set the core yarn feeding speed to 1m / min, the core yarn tension to 0.1cN, and the PVA nanofiber strip covering twist to 300T / m. Then feed the PVA nanofiber strip onto the machine and spirally cover it onto the surface of the silver-plated nylon filament to obtain a composite core yarn. Then set the composite core yarn feeding speed to 2m / min, the composite core yarn tension to 1cN, and the outer electrode covering twist to 100T / m. Feed the silver-plated nylon filament onto the machine and spirally cover it onto the surface of the composite core yarn to obtain the moisture-generating core-spun yarn described in Example 1.

[0046] The morphology of the PVA nanofiber membrane obtained in step 2 of Example 1 was observed using SEM electron microscopy to confirm the formation of the nanofiber moisture-absorbing core layer in Example 1. Figure 2 As shown.

[0047] Example 2

[0048] like Figure 1 As shown, this embodiment provides a method for preparing moisture-generating core-spun yarn:

[0049] 1. PEO was added to deionized water and magnetically stirred at 800 rpm for 6 hours at 55°C. The mixture was then degassed under vacuum to obtain the PEO spinning solution. The mass ratio of PEO to deionized water was 7.5:60.

[0050] 2. Set the electrospinning machine voltage to 16kV, the distance between the spinning nozzle and the receiving device to 18cm, and the spinning solution flow rate to 0.6mL / h. Then, the PEO spinning solution is sprayed out from the spinning nozzle, dried and solidified, and a PEO nanofiber membrane is formed on the receiving device.

[0051] 3. Cut the PEO nanofiber membrane into strips 3 mm wide and bond them together to obtain PEO nanofiber strips;

[0052] 4. Feed the copper wire onto the coating yarn machine, set the core wire feeding speed to 5m / min, the core wire tension to 0.5cN, and the PEO nanofiber strip coating twist to 400T / m. Then feed the PEO nanofiber strip onto the machine and spirally coat it onto the surface of the copper wire to obtain a composite core wire. Then set the composite core wire feeding speed to 5m / min, the composite core wire tension to 2cN, and the outer electrode coating twist to 500T / m. Feed the silver-plated nylon filament onto the machine and spirally coat it onto the surface of the composite core wire to obtain the moisture-generating core-spun yarn described in Example 2.

[0053] Example 3

[0054] like Figure 1 As shown, this embodiment provides a method for preparing moisture-generating core-spun yarn:

[0055] 1. Sodium alginate was added to deionized water and stirred magnetically at 1000 rpm for 8 hours at 60°C. Vacuum degassing was then performed to obtain sodium alginate spinning solution. The mass ratio of sodium alginate to deionized water was 10:90.

[0056] 2. Set the electrospinning machine voltage to 18kV, the distance between the spinning nozzle and the receiving device to 20cm, and the spinning solution flow rate to 0.8mL / h. Then, the sodium alginate spinning solution is sprayed out from the spinning nozzle. After drying and solidification, a sodium alginate nanofiber membrane is formed on the receiving device.

[0057] 3. Cut the sodium alginate nanofiber membrane into strips 5 mm wide and bond them together to obtain sodium alginate nanofiber strips;

[0058] 4. Load the carbon fiber filaments onto the coating machine, set the core filament feeding speed to 10 m / min, the core filament tension to 10 cN, and the sodium alginate nanofiber strip coating twist to 500 T / m. Then, load the sodium alginate nanofiber strip onto the surface of the carbon fiber filaments in a spiral manner to obtain a composite core filament. Next, set the composite core filament feeding speed to 10 m / min, the composite core filament tension to 10 cN, and the external electrode coating twist to 1000 T / m. Load the silver-plated nylon filaments onto the surface of the composite core filaments in a spiral manner to obtain the moisture-generating core-spun yarn described in Example 3.

[0059] Comparative Example 1

[0060] This comparative example provides a moisture-generating core-spun yarn and its preparation method. Compared with Example 2, the difference is that the outer layer polar coating twist is 1500T / m. The remaining steps are the same as in Example 2, and will not be repeated here.

[0061] The moisture-generating core-spun yarns prepared in Examples 1-3 and Comparative Example 1 were all prepared according to... Figure 3 Assembled as shown, the output voltage and current curves of the yarn at a relative humidity of 60% were measured under different external electrode coating twist conditions. The results are as follows. Figures 4-5 As shown, under the low twist condition of 100T / m, the voltage and current output performance is low. As the twist increases to 500T / m, the voltage and current increase. When the twist increases to 1000T / m, the voltage and current decrease. When the twist increases to 1500T / m, the voltage and current approach 0.

[0062] 3D microscopy was used to photograph Examples 1-3 to confirm the differences in surface electrode spacing in Examples 1-3. Figure 6 As shown, when the twist is too low, the spacing is too large, causing the core layer to completely absorb moisture. When the twist is too high, the silver-plated filaments are tightly packed without pores, which is not conducive to water molecules entering the core layer, making it difficult to generate gradient differences and causing a decrease in output voltage.

[0063] Comparative Example 2

[0064] This comparative example provides a moisture-generating core-spun yarn and its preparation method. Compared to Example 2, the difference lies in that the core layer is a PVA film; the remaining steps are the same as in Example 2 and will not be repeated here. The PVA film is spread from a 10% PVA solution into an acrylic tank, placed in a vacuum drying oven for defoaming and drying for 12 hours, and then removed and cut into strips of the same specifications as in Example 2. The moisture generator prepared in this comparative example is tested, and... Figure 7As shown, the results revealed that the sample lacked nanostructures, resulting in poor moisture absorption and significantly lower output performance compared to Example 2.

[0065] In summary, the moisture-generating core-spun yarn described in this application improves the yarn's power generation performance by optimizing the yarn structure. By changing the twist of the outer electrode, the contact area between moisture and the yarn is controlled, demonstrating that the contact area should not be too large or too small. By reasonably controlling the size of the contact area between moisture and the yarn, the moisture-generating performance of the yarn can be effectively improved.

[0066] It should be noted that the above embodiments are only used to illustrate the technical solutions of this application and are not intended to limit it. Although this application has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of this application without departing from the spirit and scope of the technical solutions of this application, and all such modifications and substitutions should be covered within the scope of the claims of this application.

Claims

1. A moisture-generating core-spun yarn, characterized in that, The core-spun yarn is composed of an inner electrode, a power-generating layer, and an outer electrode, forming a three-layer core-sheath structure; the inner electrode is located in the yarn core layer, the power-generating layer is located in the middle layer of the yarn, and the outer electrode is located in the yarn sheath layer. The internal electrode comprises any one of silver-plated filament, metal wire, or carbon fiber. The power generation layer is a moisture-absorbing nanofiber membrane; The external electrode is a silver-plated filament.

2. The moisture-generating core-spun yarn according to claim 1, characterized in that, The core layer of the core-spun yarn has a thickness of 10~100μm, the intermediate layer has a thickness of 50~300μm, and the sheath layer has a thickness of 80~500μm.

3. The moisture-generating core-spun yarn according to claim 1, characterized in that, The linear density of the silver-plated filament is 15~35 tex.

4. A method for preparing a moisture-generating core-spun yarn, characterized in that, Includes the following steps: Add the moisture-absorbing material to the solvent, stir magnetically at 50~60℃ and 500~1000rpm for 5~8h, and degas under vacuum to obtain the moisture-absorbing material spinning solution. The hygroscopic material spinning solution is sprayed from the spinning nozzle using an electrospinning device. After drying and curing, it forms a hygroscopic nanofiber membrane on the receiving device. The hygroscopic nanofiber membrane is then cut and bonded to obtain hygroscopic nanofiber strips with a width of 2-5 mm. Using the inner electrode as the core wire, a moisture-absorbing nanofiber strip is spirally wrapped onto the surface of the core wire using a coating machine to obtain a composite core wire; then, using the coating machine, an outer electrode is spirally wrapped onto the surface of the composite core wire to obtain a moisture-generating core-spun yarn.

5. The method for preparing a moisture-generating core-spun yarn according to claim 4, characterized in that, The moisture-absorbing material includes any one of polyvinyl alcohol (PVA), polyethylene oxide (PEO), and sodium alginate.

6. The method for preparing a moisture-generating core-spun yarn according to claim 4, characterized in that, The solvent is deionized water.

7. The method for preparing a moisture-generating core-spun yarn according to claim 4, characterized in that, The mass ratio of the moisture-absorbing material to the solvent is (5~10):(45~90).

8. The method for preparing a moisture-generating core-spun yarn according to claim 4, characterized in that, The electrospinning parameters are: voltage 15~18kV, distance between nozzle and receiving device 15~20cm, and spinning solution flow rate 0.5~0.8mL / h.

9. The method for preparing a moisture-generating core-spun yarn according to claim 4, characterized in that, The spinning parameters of the covered yarn machine are: core yarn feeding speed 1~10m / min, core yarn tension 0.1~10cN, moisture-absorbing nanofiber strip twist 300~600T / m; composite core yarn feeding speed 2~10m / min, composite core yarn tension 0.1~10cN, and outer electrode covering twist 100~1000T / m.

10. An application of a moisture-generating core-spun yarn, characterized in that, The moisture-generating core-spun yarn can be used in smart wearable devices and self-powered power supplies.

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