Phase-change synergetic thermoelectric fiber for human body microenvironment regulation and heat energy collection, emulsion wet spinning preparation method and application of phase-change synergetic thermoelectric fiber

Abstract

The invention discloses a phase-change synergetic thermoelectric fiber for human body microenvironment regulation and heat energy collection, and an emulsion wet spinning preparation method and application of the phase-change synergetic thermoelectric fiber. The preparation method comprises the following steps: by taking aramid nanofiber, polyvinylidene fluoride and the like as structural matrixes, constructing a continuous conductive phase by introducing a conductive material, and dispersing a phase-change material in the continuous conductive phase in an emulsion form to form a spinning solution; and performing emulsion wet spinning forming, water system coagulating bath curing and conductive polymer solution dipping treatment to obtain the conductive polymer composite material. The fiber can realize continuous conversion from heat energy to electric energy through Seebeck effect under the condition of tiny temperature difference between human skin and environment; meanwhile, the phase change material contained in the fiber generates quasi-isothermal phase change in a temperature range close to the comfortable temperature range of a human body, body surface heat can be dynamically absorbed and released, microenvironment thermal comfort regulation and control are achieved, and the axial temperature difference gradient of the fiber is further expanded by means of the phase change latent heat effect, so that the thermoelectric output performance is synergistically enhanced.

Description

Technical Field

[0001] This invention belongs to the interdisciplinary technical field of thermal management / energy materials and functional fibers, specifically relating to a phase change synergistic thermoelectric fiber for human microenvironment regulation and heat energy harvesting, its emulsion wet spinning preparation method and application. Background Technology

[0002] With the rapid growth of wearable electronic devices and the demand for personalized thermal management, the development of smart textiles capable of simultaneously achieving heat harvesting and body temperature regulation is of great significance. Thermoelectric materials can directly convert the minute temperature difference between the human body and the environment into electrical energy using the Seebeck effect, providing continuous power for wearable devices; phase change materials can absorb or release a large amount of latent heat through a reversible phase change process within a specific temperature range, achieving dynamic temperature buffering and regulation of the body surface microenvironment. However, efficiently integrating these two functions into a single textile fiber system and achieving synergistic enhancement of functions still faces many challenges.

[0003] Existing technologies mainly suffer from the following limitations: First, their functions are limited. While traditional thermoelectric fibers can generate electricity, they often have high rigidity, insufficient flexibility, and limited conversion efficiency at low temperature differences. Traditional phase change fibers, while capable of temperature regulation, generally suffer from problems such as easy detachment of energy storage units (e.g., phase change microcapsules), low latent heat utilization efficiency, and poor cycle stability, and they lack energy harvesting capabilities. Second, their integration methods are simplistic and lack synergy. Current research often employs methods such as coating, lamination, or physical blending to mechanically combine thermoelectric modules with phase change modules. For example, in their work "Phase-Transition-Promoted Thermoelectric Textiles Based on Twin Surface-Modified CNT Fibers" and "A Tri-Mode Photothermal, Phase-Change, and Radiative-Cooling Film for All-Day Thermoelectric Generation," Yu et al. prepared phase change microcapsules through interfacial polymerization and then coated them onto the surface of prefabricated thermoelectric fibers, or bonded phase change films to discrete thermoelectric devices. These methods are merely physical superpositions of functions, with weak interfacial bonding between components, easily leading to performance degradation and poor durability. Furthermore, they fail to achieve integrated and synergistic effects of thermoelectric effects and quasi-isothermal phase transition characteristics. Thirdly, the preparation process is complex and difficult to scale up. Many schemes rely on chemical vapor deposition, multi-step interfacial polymerization, or complex post-processing, resulting in cumbersome processes, high costs, and difficulty in achieving continuous and large-scale fiber preparation, thus limiting their practical application prospects.

[0004] Therefore, there is an urgent need to develop a new material system and preparation strategy aimed at achieving in-situ integrated phase change thermal regulation and thermoelectric conversion functional units within a single fiber. While ensuring good flexibility and wearing comfort, the fiber should actively maintain and enhance the axial temperature difference through the inherent "quasi-isothermal" characteristics of phase change materials, thereby synergistically improving its thermoelectric output efficiency under minute temperature differences and simultaneously achieving dynamic intelligent thermal regulation of the human body's microenvironment. Developing such novel multifunctional fibers with both inherent performance synergy mechanisms and prospects for large-scale production is of crucial significance for promoting the practical application of next-generation self-powered smart textiles. Summary of the Invention

[0005] The purpose of this invention is to provide a phase change synergistic thermoelectric fiber for human microenvironment regulation and heat harvesting, its emulsion wet spinning preparation method, and its application, in order to solve the following key technical problems in the field of smart textiles: the low thermoelectric conversion efficiency of traditional thermoelectric fibers under small temperature difference conditions, and the difficulty in balancing flexibility, weavability, and wearability; the problem that existing phase change temperature-regulating fibers have single functions and degraded temperature-regulating performance; the problem that existing thermoelectric-phase change composite systems have only physical superposition between functional units, weak interface bonding, poor durability, and fail to achieve in-situ synergy and performance enhancement of thermoelectric conversion and phase change heat storage at the mechanism level; and the problem that existing preparation processes are complex and cumbersome, making it difficult to meet the requirements of continuous and large-scale production.

[0006] To achieve the above objectives, the present invention provides the following technical solution: A method for preparing phase change synergistic thermoelectric fibers for human microenvironment regulation and heat harvesting via emulsion wet spinning includes the following steps: (1) The polymer is dissolved in a dissolving system to prepare a polymer solution; the polymer is at least one of poly(p-phenylene terephthalamide) (PPTA), polyvinylidene fluoride (PVDF), polyvinylidene fluoride-hexafluoropropylene copolymer (PVDF-HFP), polyacrylonitrile (PAN), polyvinylpyrrolidone (PVP), polyamic acid (PAA) and cellulose derivatives; (2) Add conductive material to the polymer solution obtained in step (1) and sonicate to make the conductive material uniformly dispersed in the aramid nanofiber solution; (3) Add emulsifier to the mixed solution obtained in step (2) and stir to make the emulsifier evenly dispersed in the mixed solution; (4) Add phase change material to the solution obtained in step (3) and shear emulsify; (5) Use pure water as the coagulation bath; (6) The spinning microemulsion obtained in step (4) is wet-spun, and the spun nascent wet fibers fall into the coagulation bath obtained in step (5). (7) The fibers obtained in step (6) are impregnated in a conductive polymer solution; (8) Dry the fiber obtained in step (7) to obtain phase change synergistic thermoelectric fiber.

[0007] Furthermore, in step (1), the poly(p-phenylene terephthalamide) (PPTA) fiber is dissolved in a DMSO / KOH system to form a uniform aramid nanofiber solution, and the amount of KOH added is the same as the mass of the poly(p-phenylene terephthalamide).

[0008] A homogeneous polymer solution was prepared by dissolving polyvinylidene fluoride (PVDF), vinylidene fluoride-hexafluoropropylene copolymer (PVDF-HFP), polyacrylonitrile (PAN), polyvinylpyrrolidone (PVP), polyamic acid (PAA), and cellulose derivatives in polar aprotic solvents (such as DMSO, DMF, DMAc, NMP, etc.).

[0009] Further, in step (1), the polymer concentration in the polymer solution is 1~6 wt.%, preferably 2 wt.%, and the processing temperature in step (1) is room temperature, i.e. 20~30 ℃.

[0010] Further, in step (2), the conductive material is one or a mixture of two or more of zinc oxide, zinc selenide, bismuth telluride, single-walled carbon nanotubes, double-walled carbon nanotubes, and multi-walled carbon nanotubes in any proportion, preferably single-walled carbon nanotubes. The amount of conductive material added is 0.5-3% of the total mass of the polymer solution in step (1), preferably 1.5 wt.%. The ultrasonic power is 100-300 W, and the ultrasonic time is 2-3 h. Preferably, 150 W is used for 10-30 min, 200 W for 70-90 min, and 300 W for 70-90 min.

[0011] Further, in step (3), the emulsifier is one or more of Pluronic F127, Pluronic P123, sodium cholate, Span-80 and sodium dodecyl sulfate in any proportion, the content of the emulsifier is 4 to 9 wt.% of the total mass of the mixed solution, preferably 8 wt.%, and the stirring time is 1 to 3 h.

[0012] Further, in step (4), the phase change material is one or a mixture of two or more of fatty acids, n-alkanes, paraffins, polyols, polyethylene glycol, and polyolefins in any proportion; the mass ratio of the phase change material to the polymer is 9:1 to 5:5, preferably 7:3. The shear emulsification temperature is 30~270 ℃, and the time is 2~4 h; Furthermore, the fatty acids refer to at least one of decanoic acid, lauric acid, myristic acid, pentadecanoic acid, palmitic acid, icosanoic acid, and stearic acid; the n-alkanes refer to at least one of dodecane, tetradecane, pentadecane, hexadecane, heptadecane, octadecane, nonadecane, eicosane, docosane, and octacosane; and the polyols refer to at least one of erythritol, galactitol, and pentaerythritol. Octadecane is preferred.

[0013] Furthermore, in step (6), the coagulation bath temperature during the spinning process is 0~40 ℃.

[0014] Further, in step (7), the conductive polymer solution is one or more of PEDOT:PSS / DMSO, PEDOT:PSS / DMF, polyaniline solution, and polypyrrole nanodispersion in any proportion, the concentration of the conductive polymer solution is 60~80 wt.%, preferably PEDOT:PSS / DMSO solution, and the immersion time is 10 min~1 h.

[0015] Furthermore, the temperature of the dried fiber in (8) is 20~40 °C.

[0016] The above preparation method yields phase change synergistic thermoelectric fibers for human microenvironment regulation and heat energy harvesting.

[0017] The present invention also provides the application of the above-mentioned phase change synergistic thermoelectric fibers in wearable devices, smart textile equipment and smart clothing.

[0018] The effective benefits of this invention are as follows: This invention provides a "one-step emulsion wet spinning method" that simultaneously completes phase change microcapsule formation, thermoelectric network construction, and interface coupling within a single fiber. This achieves a closed-loop synergy of "phase change latent heat amplification of temperature difference - continuous temperature difference-driven thermoelectricity - electrical energy feedback management of the thermal environment," taking into account high latent heat, high electrical conductivity, high flexibility, and continuous production. It provides core materials and a scalable technical route for self-powered smart textiles. The phase change synergistic thermoelectric fiber of this invention has advantages such as high Seebeck coefficient, good flexibility, good biocompatibility, no leakage, low toxicity, low cost, and good thermal cycling stability. Among these advantages, Figure 2 The Seebeck coefficient of the phase change synergistic thermoelectric fiber obtained in Example 4 was 56.54 μV / K, and the Seebeck coefficient of the phase change synergistic thermoelectric fiber obtained in Example 5 was 52.5 μV / K. Meanwhile, the goodness of fit R between the two was... 2 Both are close to 1, indicating a very strong linear positive correlation between voltage and temperature difference; Figure 3The latent heat release duration of Example 4 reached 1539 s, while the release time of Comparative Example 3 was shorter. At the same time, during the cooling process, the temperature decay of Example 4 was more gradual and the voltage was always higher than that of the Comparative Example. This shows that Example 4 can not only stably release the latent heat of phase change over a long period of 1539 s, but also achieve more efficient "phase change heat storage and release - thermoelectric conversion" synergistic performance through a more gradual temperature change and better voltage output. It is suitable for large-scale application in the field of smart wearable devices. Attached Figure Description

[0019] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly described below. Obviously, the drawings described below are merely some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without any creative effort.

[0020] Figure 1 Photographs and SEM images of the phase change synergistic thermoelectric fibers prepared in Example 4; Figure 2 Seebeck coefficient diagrams for the phase change synergistic thermoelectric fibers prepared in Examples 4 and 5; Figure 3 The image shows the DSC curve of the phase change synergistic thermoelectric fiber prepared in Example 4. Figure 4 The image shows a FLIR comparison of the phase change synergistic thermoelectric fiber prepared in Example 4 with the pure fiber prepared in Comparative Example 1 and the phase change fiber prepared in Comparative Example 2. Figure 5 The graph shows the relationship between the hot-end temperature and output voltage of the phase change synergistic thermoelectric fiber prepared in Example 4 and the thermoelectric fiber prepared in Comparative Example 3 over time. Figure 6 The image shows a physical diagram of a phase change synergistic thermoelectric fiber device and its voltage response test under light pressure. Detailed Implementation

[0021] The technical solution of the present invention will be described in detail below with reference to the accompanying drawings and embodiments. Example 1

[0022] A method for preparing phase change synergistic thermoelectric fibers for human microenvironment regulation and heat harvesting via emulsion wet spinning includes the following steps: (1) 1.12 g of poly(p-phenylene terephthalamide) (PPTA) and an equal mass of 1.12 g of KOH were dissolved in 100 mL of dimethyl sulfoxide. KOH was used to chemically etch and swell the PPTA. PPTA and KOH were used as the total solute. The mixture was stirred at room temperature for 7 days to obtain a 2 wt.% ANFs (aramid nanofibers) solution. (2) 0.075 g of single-walled carbon nanotubes were added to 10 g of ANFs solution and subjected to segmented ultrasonic treatment at room temperature for 3 h, with the ultrasonic power gradually increasing from 150 W to 300 W. Specifically, the ultrasonic treatment was performed at 150 W for 20 min, 200 W for 80 min, and 300 W for 80 min. (3) To stabilize the emulsion system and provide interfacial support for the efficient encapsulation of the phase change material, 0.806 g of the emulsifier Pluronic F127 (CAS: 9003-11-6) was added to 10.075 g of the above mixed solution and stirred at room temperature for 1.5 h. The emulsifier content was 8 wt.% of the mass of the mixed solution. (4) Add 0.47 g of octadecane to the above solution, emulsify and stir at 37 °C for 3 h to obtain a uniform emulsion, wherein the stirring rate is 1000 rpm. From the 10 g aramid nanofiber solution in step (2), it can be seen that the mass of aramid nanofiber is 0.2 g, and the ratio of the amount of phase change material added to the mass of aramid nanofiber is 7:3. (5) Pour 1000 mL of water into the coagulation bath tank as a coagulation bath.

[0023] (6) The microemulsion obtained in (4) is placed in a wet spinning machine for wet spinning. Its end outlet falls into the coagulation bath of (5) and the temperature is maintained at 26 ℃. The fiber diameter is 221 μm.

[0024] (7) The nascent wet fibers obtained in (6) were briefly impregnated in a conductive polymer PEDOT:PSS / DMSO solution for 30 min. The concentration of PEDOT:PSS in DMSO was 70 wt.% in the conductive polymer solution. (8) The fiber obtained in (7) was dried in an oven at 40 °C for 2 h to obtain phase change synergistic thermoelectric fiber. Example 2

[0025] A method for preparing phase change synergistic thermoelectric fibers for human microenvironment regulation and heat harvesting via emulsion wet spinning includes the following steps: (1) 1.12 g of poly(p-phenylene terephthalamide) (PPTA) and an equal mass of 1.12 g of KOH were dissolved in 100 mL of dimethyl sulfoxide. KOH was used to chemically etch and swell the PPTA. PPTA and KOH were used as the total solute. The solution was stirred at room temperature for 7 days to obtain a 2 wt.% ANFs solution. (2) 0.1 g of single-walled carbon nanotubes were added to 10 g of ANFs solution and subjected to segmented ultrasonic treatment at room temperature for 3 h, with the ultrasonic power gradually increasing from 150 W to 300 W. Specifically, ultrasonic treatment was performed at 150 W for 20 min, 200 W for 80 min, and 300 W for 80 min. (3) In order to stabilize the emulsion system and provide interfacial support for the efficient encapsulation of the phase change material, 0.808 g of emulsifier Pluronic F127 was added to 10.1 g of the above mixed solution and stirred at room temperature for 1.5 h, wherein the emulsifier content was 8 wt.% of the mass of the mixed solution. (4) Add 0.47 g of octadecane to the above solution, emulsify and stir at 37 °C for 3 h to obtain a uniform emulsion, wherein the stirring rate is 1000 rpm. From the 10 g aramid nanofiber solution in step (2), it can be seen that the mass of aramid nanofiber is fixed at 0.2 g, and the ratio of the amount of phase change material added to the mass of aramid nanofiber is 7:3. (5) Pour 1000 mL of water into the coagulation bath tank as a coagulation bath.

[0026] (6) The microemulsion obtained in (4) is placed in a wet spinning machine for wet spinning. Its end outlet falls into the coagulation bath of (5) and the temperature is maintained at 26 ℃. The fiber diameter is 224 μm.

[0027] (7) The nascent wet fibers obtained in (6) were briefly impregnated in a conductive polymer PEDOT:PSS / DMSO solution for 30 min. The concentration of PEDOT:PSS in DMSO was 70 wt.% in the conductive polymer solution. (8) The fiber obtained in (7) was dried in an oven at 40 °C for 2 h to obtain phase change synergistic thermoelectric fiber. Example 3

[0028] A method for preparing phase change synergistic thermoelectric fibers for human microenvironment regulation and heat harvesting via emulsion wet spinning includes the following steps: (1) 1.12 g of poly(p-phenylene terephthalamide) (PPTA) and an equal mass of 1.12 g of KOH were dissolved in 100 mL of dimethyl sulfoxide. KOH was used to chemically etch and swell the PPTA. PPTA and KOH were used as the total solute. The solution was stirred at room temperature for 7 days to obtain a 2 wt.% ANFs solution. (2) 0.125 g of single-walled carbon nanotubes were added to 10 g of ANFs solution and subjected to segmented ultrasonic treatment at room temperature for 3 h, with the ultrasonic power gradually increasing from 150 W to 300 W. Specifically, the ultrasonic treatment was performed at 150 W for 20 min, 200 W for 80 min, and 300 W for 80 min. (3) In order to stabilize the emulsion system and provide interfacial support for the efficient encapsulation of the phase change material, 0.81 g of emulsifier Pluronic F127 was added to 10.125 g of the above mixed solution and stirred at room temperature for 1.5 h, wherein the emulsifier content was 8 wt.% of the mass of the mixed solution. (4) Add 0.47 g of octadecane to the above solution, emulsify and stir at 37 °C for 3 h to obtain a uniform emulsion, wherein the stirring rate is 1000 rpm. From the 10 g aramid nanofiber solution in step (2), it can be seen that the mass of aramid nanofiber is fixed at 0.2 g, and the ratio of the amount of phase change material added to the mass of aramid nanofiber is 7:3. (5) Pour 1000 mL of water into the coagulation bath tank as a coagulation bath.

[0029] (6) The microemulsion obtained in (4) is placed in a wet spinning machine for wet spinning. Its end outlet falls into the coagulation bath of (5) and the temperature is maintained at 26 ℃. The fiber diameter is 231 μm.

[0030] (7) The nascent wet fibers obtained in (6) were briefly impregnated in a conductive polymer PEDOT:PSS / DMSO solution for 30 min. The concentration of PEDOT:PSS in DMSO was 70 wt.% in the conductive polymer solution. (8) The fiber obtained in (7) was dried in an oven at 40 °C for 2 h to obtain phase change synergistic thermoelectric fiber. Example 4

[0031] A method for preparing phase change synergistic thermoelectric fibers for human microenvironment regulation and heat harvesting via emulsion wet spinning includes the following steps: (1) 1.12 g of poly(p-phenylene terephthalamide) (PPTA) and an equal mass of 1.12 g of KOH were dissolved in 100 mL of dimethyl sulfoxide. KOH was used to chemically etch and swell the PPTA. PPTA and KOH were used as the total solute. The solution was stirred at room temperature for 7 days to obtain a 2 wt.% ANFs solution. (2) 0.15 g of single-walled carbon nanotubes were added to 10 g of ANFs solution and subjected to segmented ultrasonic treatment at room temperature for 3 h, with the ultrasonic power gradually increasing from 150 W to 300 W. Specifically, ultrasonic treatment was performed at 150 W for 20 min, 200 W for 80 min, and 300 W for 80 min. (3) In order to stabilize the emulsion system and provide interfacial support for the efficient encapsulation of the phase change material, 0.812 g of emulsifier Pluronic F127 was added to 10.15 g of the above mixed solution and stirred at room temperature for 1.5 h, wherein the emulsifier content was 8 wt.% of the mass of the mixed solution. (4) Add 0.47 g of octadecane to the above solution, emulsify and stir at 37 °C for 3 h to obtain a uniform emulsion, wherein the stirring rate is 1000 rpm. From the 10 g aramid nanofiber solution in step (2), it can be seen that the mass of aramid nanofiber is fixed at 0.2 g, and the ratio of the amount of phase change material added to the mass of aramid nanofiber is 7:3. (5) Pour 1000 mL of water into the coagulation bath tank as a coagulation bath.

[0032] (6) The microemulsion obtained in (4) is placed in a wet spinning machine for wet spinning. Its end outlet falls into the coagulation bath of (5) and the temperature is maintained at 26 ℃. The fiber diameter is 237 μm.

[0033] (7) The nascent wet fibers obtained in (6) were briefly impregnated in a conductive polymer PEDOT:PSS / DMSO solution for 30 min. The concentration of PEDOT:PSS in DMSO was 70 wt.% in the conductive polymer solution. (8) The fiber obtained in (7) was dried in an oven at 40 °C for 2 h to obtain phase change synergistic thermoelectric fiber. Example 5

[0034] A method for preparing phase change synergistic thermoelectric fibers for human microenvironment regulation and heat harvesting via emulsion wet spinning includes the following steps: (1) 1.12 g of poly(p-phenylene terephthalamide) (PPTA) and an equal mass of 1.12 g of KOH were dissolved in 100 mL of dimethyl sulfoxide. KOH was used to chemically etch and swell the PPTA. PPTA and KOH were used as the total solute. The solution was stirred at room temperature for 7 days to obtain a 2 wt.% ANFs solution. (2) 0.175 g of single-walled carbon nanotubes were added to 10 g of ANFs solution and subjected to segmented ultrasonic treatment at room temperature for 3 h, with the ultrasonic power gradually increasing from 150 W to 300 W. Specifically, the ultrasonic treatment was performed at 150 W for 20 min, 200 W for 80 min, and 300 W for 80 min. (3) In order to stabilize the emulsion system and provide interfacial support for the efficient encapsulation of the phase change material, 0.814 g of emulsifier Pluronic F127 was added to 10.175 g of the above mixed solution and stirred at room temperature for 1.5 h, wherein the emulsifier content was 8 wt.% of the mass of the mixed solution. (4) Add 0.47 g of octadecane to the above solution, emulsify and stir at 37 °C for 3 h to obtain a uniform emulsion, wherein the stirring rate is 1000 rpm. From the 10 g aramid nanofiber solution in step (2), it can be seen that the mass of aramid nanofiber is fixed at 0.2 g, and the ratio of the amount of phase change material added to the mass of aramid nanofiber is 7:3. (5) Pour 1000 mL of water into the coagulation bath tank as a coagulation bath.

[0035] (6) The microemulsion obtained in (4) is placed in a wet spinning machine for wet spinning. Its end outlet falls into the coagulation bath of (5) and the temperature is maintained at 26 ℃. The fiber diameter is 242 μm.

[0036] (7) The nascent wet fibers obtained in (6) were briefly impregnated in a conductive polymer PEDOT:PSS / DMSO solution for 30 min. The concentration of PEDOT:PSS in DMSO was 70 wt.% in the conductive polymer solution. (8) The fiber obtained in (7) was dried in an oven at 40 °C for 2 h to obtain phase change synergistic thermoelectric fiber. Example 6

[0037] A method for preparing phase change synergistic thermoelectric fibers for human microenvironment regulation and heat harvesting via emulsion wet spinning includes the following steps: (1) 2.24 g of polyvinylidene fluoride (PVDF) particles were dissolved in 100 mL of dimethyl sulfoxide and stirred at room temperature for 7 days to obtain a polymer solution of 2 wt.%; (2) 0.15 g of single-walled carbon nanotubes were added to 10 g of polymer solution and subjected to segmented ultrasonic treatment at room temperature for 3 h, with the ultrasonic power gradually increasing from 150 W to 300 W. Specifically, the ultrasonic treatment was performed at 150 W for 20 min, 200 W for 80 min, and 300 W for 80 min. (3) In order to stabilize the emulsion system and provide interfacial support for the efficient encapsulation of the phase change material, 0.812 g of emulsifier Pluronic F127 was added to 10.15 g of the above mixed solution and stirred at room temperature for 1.5 h, wherein the emulsifier content was 8 wt.% of the mass of the mixed solution. (4) Add 0.47 g of octadecane to the above solution, emulsify and stir at 37 °C for 3 h to obtain a uniform emulsion, wherein the stirring speed is 1000 rpm. From the 10 g polymer solution in step (2), it can be seen that the mass of the polymer is fixed at 0.2 g, and the mass ratio of the phase change material added to the polymer is 7:3; (5) Pour 1000 mL of water into the coagulation bath tank as a coagulation bath.

[0038] (6) The microemulsion obtained in (4) is placed in a wet spinning machine for wet spinning, and its end outlet falls into the coagulation bath in (5) and the temperature is maintained at 26 ℃.

[0039] (7) The nascent wet fibers obtained in (6) were briefly impregnated in a conductive polymer PEDOT:PSS / DMSO solution for 30 min. The concentration of PEDOT:PSS in DMSO was 70 wt.% in the conductive polymer solution. (8) The fiber obtained in (7) was dried in an oven at 40 °C for 2 h to obtain phase change synergistic thermoelectric fiber. Example 7

[0040] A method for preparing phase change synergistic thermoelectric fibers for human microenvironment regulation and heat harvesting via emulsion wet spinning includes the following steps: (1) 2.24 g of polyvinylidene fluoride (PVDF) particles were dissolved in 100 mL of dimethyl sulfoxide and stirred at room temperature for 7 days to obtain a polymer solution of 2 wt.%; (2) 0.175 g of single-walled carbon nanotubes were added to 10 g of polymer solution and subjected to segmented ultrasonic treatment at room temperature for 3 h, with the ultrasonic power gradually increasing from 150 W to 300 W. Specifically, the ultrasonic treatment was performed at 150 W for 20 min, 200 W for 80 min, and 300 W for 80 min. (3) In order to stabilize the emulsion system and provide interfacial support for the efficient encapsulation of the phase change material, 0.814 g of emulsifier Pluronic F127 was added to 10.175 g of the above mixed solution and stirred at room temperature for 1.5 h, wherein the emulsifier content was 8 wt.% of the mass of the mixed solution. (4) Add 0.47 g of octadecane to the above solution, emulsify and stir at 37 °C for 3 h to obtain a uniform emulsion, wherein the stirring rate is 1000 rpm. From the 10 g polymer solution in step (2), it can be seen that the mass of the polymer is fixed at 0.2 g, and the ratio of the amount of phase change material added to the mass of the polymer is 7:3. (5) Pour 1000 mL of water into the coagulation bath tank as a coagulation bath.

[0041] (6) The microemulsion obtained in (4) is placed in a wet spinning machine for wet spinning, and its end outlet falls into the coagulation bath in (5) and the temperature is maintained at 26 ℃.

[0042] (7) The nascent wet fibers obtained in (6) were briefly impregnated in a conductive polymer PEDOT:PSS / DMSO solution for 30 min. The concentration of PEDOT:PSS in DMSO was 70 wt.% in the conductive polymer solution. (8) The fiber obtained in (7) was dried in an oven at 40 °C for 2 h to obtain phase change synergistic thermoelectric fiber. Comparative Example 1

[0043] (1) 1.12 g of poly(p-phenylene terephthalamide) (PPTA) and an equal mass of KOH were dissolved in 100 mL of dimethyl sulfoxide. KOH was used to chemically etch and swell the PPTA. PPTA and KOH were used as the total solute. The solution was stirred at room temperature for 7 days to obtain a 2 wt.% ANFs solution. (2) Pour 1000 mL of water into the coagulation bath tank as a coagulation bath.

[0044] (3) The ANFs solution obtained in (1) is placed in a wet spinning machine for wet spinning, and its end outlet falls into the coagulation bath of (2) and the temperature is maintained at 26 ℃.

[0045] (4) The fiber obtained in (3) was dried in an oven at 40 °C for 2 h to obtain pure fiber. Comparative Example 2

[0046] (1) 1.12 g of poly(p-phenylene terephthalamide) (PPTA) and an equal mass of KOH were dissolved in 100 mL of dimethyl sulfoxide. KOH was used to chemically etch and swell the PPTA. PPTA and KOH were used as the total solute. The solution was stirred at room temperature for 7 days to obtain a 2 wt.% ANFs solution. (2) To stabilize the emulsion system and provide interfacial support for the efficient encapsulation of phase change materials, 0.8 g of emulsifier Pluronic F127 was added to 10 g of ANFs solution and stirred at room temperature for 1.5 h. The emulsifier content was 8 wt.% of the mass of the ANFs solution. (3) Add 0.47 g of octadecane to the above solution, emulsify and stir at 37 °C for 3 h to obtain a uniform emulsion, wherein the stirring rate is 1000 rpm. From the 10 g aramid nanofiber solution in step (2), it can be seen that the mass of aramid nanofiber is fixed at 0.2 g, and the ratio of the amount of phase change material added to the mass of polymer is 7:3. (4) Pour 1000 mL of water into the coagulation bath tank as a coagulation bath.

[0047] (5) The microemulsion obtained in (3) is placed in a wet spinning machine for wet spinning, and its end outlet falls into the coagulation bath in (4) and the temperature is maintained at 26 ℃.

[0048] (6) The fiber obtained in (5) was dried in an oven at 40 °C for 2 h to obtain phase change fiber. Comparative Example 3

[0049] (1) 1.12 g of poly(p-phenylene terephthalamide) (PPTA) and an equal mass of KOH were dissolved in 100 mL of dimethyl sulfoxide. KOH was used to chemically etch and swell the PPTA. PPTA and KOH were used as the total solute. The solution was stirred at room temperature for 7 days to obtain a 2 wt.% ANFs solution. (2) 0.15 g of single-walled carbon nanotubes were added to 10 g of ANFs solution and subjected to segmented ultrasonic treatment at room temperature for 3 h, with the ultrasonic power gradually increasing from 150 W to 300 W. Specifically, ultrasonic treatment was performed at 150 W for 20 min, 200 W for 80 min, and 300 W for 80 min. (3) Pour 1000 mL of water into the coagulation bath tank as a coagulation bath.

[0050] (4) The microemulsion obtained in (2) is placed in a wet spinning machine for wet spinning, and its end outlet falls into the coagulation bath of (3) and the temperature is maintained at 26 ℃.

[0051] (5) The nascent wet fibers obtained in (4) were briefly impregnated in a conductive polymer PEDOT:PSS / DMSO solution for 30 min. The concentration of PEDOT:PSS in DMSO was 70 wt.% in the conductive polymer solution. (6) The fiber obtained in (5) was dried in an oven at 40 °C for 2 h to obtain thermoelectric fiber.

[0052] The experimental results are characterized as follows: The phase change synergistic thermoelectric fiber prepared in Example 4 was characterized by SEM. Figure 1 The results show that the rough and porous structure of the fiber increases the specific surface area of ​​the fiber. On the one hand, it can increase the interfacial contact area of ​​the thermoelectric material, which is beneficial to the transport of charge carriers. On the other hand, the microscale effect of the porous structure may also regulate thermoelectric parameters such as Seebeck coefficient and electrical conductivity. At the same time, the pores on the rough surface can serve as loading sites for the phase change medium, enhancing the bonding force between the phase change material and the fiber matrix. In addition, the porous structure can provide more channels for heat transfer during the phase change process, thereby improving the heat storage and release efficiency.

[0053] The thermoelectric properties of the phase change synergistic thermoelectric fibers prepared in Examples 4 and 5 were tested. Figure 2The results show that both exhibit a linear increase in voltage with increasing temperature difference, and the goodness of fit R0 is high. 2 Both are close to 1 (0.99894 and 0.99782 respectively), indicating a strong linear correlation. The S marked in the figure is the Seebeck coefficient (i.e., the slope of the curve). The Seebeck coefficient of Example 4 (56.54 μV / K) is slightly higher than that of Example 5 (52.5 μV / K), reflecting that the former has better thermoelectric conversion efficiency than the latter.

[0054] like Figure 3 As shown, DSC tests were performed on the sample of Example 4, with the ordinate representing heat flow and the abscissa representing temperature. The curves show a significant downward endothermic peak in the 20–40°C range, corresponding to the melting process, with a melting enthalpy of 99.52 J / g, reflecting the melting behavior and crystallinity level of the sample's crystalline region. Subsequently, an upward exothermic peak appears in a slightly higher temperature range, corresponding to the recrystallization process, with a crystallization enthalpy of 108.17 J / g, indicating that the molecular chain segments after melting can rearrange to form crystals. Overall, this reflects the thermal transformation characteristics and crystallization behavior of the material.

[0055] like Figure 4 As shown, infrared thermal imaging comparative tests were conducted using 5 strands of 10 fibers, with each test sample being approximately 6 mg. The samples were tested in a 45 ℃ hot environment and a 10 ℃ cold environment. The FLIR thermal images revealed that the pure fiber (Comparative Example 1) relied solely on heat conduction, with its temperature rapidly and linearly rising to 44.9 ℃ over time, exhibiting no heat storage or temperature regulation effect. While the phase change fiber (Comparative Example 2) showed a slowly rising temperature plateau due to phase change melting and heat absorption, possessing basic heat storage and temperature regulation capabilities, it lacked a thermoelectric synergy mechanism. In contrast, the phase change synergistic thermoelectric fiber (Example 4) significantly slowed the rate of temperature change during both heating and cooling stages through the heat absorption and release effects of the phase change material. This not only achieved a heat buffer function for heat storage and temperature regulation but also reduced the temperature fluctuation range at the hot end from ±3.2 ℃ in Comparative Example 1 and ±2.7 ℃ in Comparative Example 2 to only ±1.1 ℃, maintaining a stable temperature gradient. This provided a continuous driving force for thermoelectric conversion, ultimately achieving a synergistic gain of heat storage and temperature regulation and stable temperature difference to improve thermoelectric output.

[0056] like Figure 5As shown, the hot-end temperature and output voltage of Example 4 and Comparative Example 3 were tested over time. Example 4 exhibits long-term latent heat release. The cooling process of Example 4 in the figure shows a more gradual temperature decay and a sustained latent heat release over 1539 seconds. Comparative Example 3, on the other hand, cools down quickly without a significant sustained heat release process. This indicates that the introduction of the phase change material (PCM) enables the fiber to achieve long-term latent heat release, thus delaying temperature decrease. Simultaneously, the voltage curve on the right shows that the voltage of Example 4 remains higher than that of the comparative example during the cooling process, and the voltage changes synchronously with the latent heat release. Comparative Example 3, lacking PCM, exhibits faster voltage decay and a lower value. This demonstrates that the latent heat release of the PCM provides a continuous temperature difference drive for thermoelectric conversion, achieving a synergistic effect between phase change thermal regulation and thermoelectric conversion. Compared to Comparative Example 3, which does not contain PCM, the phase change-synergistic thermoelectric fiber of Example 4 of this invention, through the introduction of PCM, simultaneously achieves long-term latent heat release and superior thermoelectric response, verifying the effectiveness of the phase change-thermoelectric synergistic design.

[0057] like Figure 6 As shown, the device prepared in Example 4 exhibits significant thermoelectric response characteristics when subjected to gentle pressure. This device employs a hybrid series-parallel connection, with fibers alternately bonded to the front and back of the fabric to form a continuous conductive circuit. In a single conductive path, current flows sequentially through two fibers (in series) to enhance the resistance and pressure sensitivity of each branch. Simultaneously, the device comprises three independent series branches, which are connected in parallel via upper and lower copper foils to reduce overall resistance, improve current carrying capacity, and optimize the uniformity of temperature stress distribution. In the initial state without external force, the reference output voltage measured using a Keithley 2450 test instrument was only 0.019 mV, indicating that the fiber fabric has excellent electrical stability under static conditions. When the experimenter applied gentle pressure to the fabric with their finger (approximately 0.5 kPa, close to the human skin's perception threshold), the voltage signal of the test system rapidly jumped to 24.233 mV, with a response amplitude exceeding 1200 times the initial value. This result confirms that the device can achieve efficient conversion of electrical signals through mechanically pressure-induced changes in its internal microstructure, exhibiting high sensitivity and high reliability. This rapid response capability to weak pressure makes it a promising candidate for applications in flexible wearable pressure sensors, electronic skin, and human physiological signal monitoring.

[0058] It should be understood that the above description is merely a representative embodiment of the present invention, and the scope of protection of the present invention includes, but is not limited to, these embodiments. Furthermore, it should be understood that those skilled in the art, after reviewing the content of this invention, can make various obvious simple changes or equivalent substitutions to the present invention, and these equivalent forms all fall within the scope of protection of the present invention.

Claims

1. A method for preparing phase change synergistic thermoelectric fibers for human microenvironment regulation and heat harvesting via emulsion wet spinning, characterized in that, The preparation process includes the following steps: (1) The polymer is dissolved in a dissolving system to prepare a polymer solution; the polymer is at least one of poly(p-phenylene terephthalamide), polyvinylidene fluoride, polyvinylidene fluoride-hexafluoropropylene copolymer, polyacrylonitrile, polyvinylpyrrolidone, polyamic acid and cellulose derivatives; (2) Add conductive material to the polymer solution obtained in step (1) and sonicate to make the conductive material uniformly dispersed in the aramid nanofiber solution; (3) Add emulsifier to the mixed solution obtained in step (2) and stir to make the emulsifier evenly dispersed in the mixed solution; (4) Add phase change material to the solution obtained in step (3) and shear emulsify; (5) Use pure water as the coagulation bath; (6) The spinning microemulsion obtained in step (4) is wet-spun, and the spun nascent wet fibers fall into the coagulation bath obtained in step (5). (7) The fibers obtained in step (6) are impregnated in a conductive polymer solution; (8) Dry the fiber obtained in step (7) to obtain phase change synergistic thermoelectric fiber.

2. The method for preparing emulsion wet spinning as described in claim 1, characterized in that, In step (2), the conductive material is one or more of zinc oxide, zinc selenide, bismuth telluride, single-walled carbon nanotubes, double-walled carbon nanotubes and multi-walled carbon nanotubes, and the amount of conductive material added is 0.5-3% of the total mass of the polymer solution in step (1); the ultrasonic power is 100-300 W and the ultrasonic time is 2-3 h.

3. The method for preparing emulsion wet spinning according to claim 1, characterized in that, In step (3), the emulsifier is one or more of Pluronic F127, Pluronic P123, sodium cholate, Span-80 and sodium dodecyl sulfate in any proportion, and the amount of emulsifier added is 4 to 9% of the total mass of the mixed solution obtained in step (2).

4. The method for preparing emulsion wet spinning according to claim 1, characterized in that, In step (4), the phase change material is one or more of fatty acids, n-alkanes, paraffins, polyols, polyethylene glycol and polyolefins in any proportion; the mass ratio of the phase change material to the polymer is 9:1 to 5:

5.

5. The method for preparing emulsion wet spinning according to claim 4, characterized in that, Fatty acids refer to at least one of the following: decanoic acid, lauric acid, myristic acid, pentadecanoic acid, palmitic acid, icosanoic acid, and stearic acid; n-alkanes refer to at least one of the following: dodecane, tetradecane, pentadecane, hexadecane, heptadecane, octadecane, nonadecane, eicosane, docosane, and octacosane; polyols refer to at least one of the following: erythritol, galactitol, and pentaerythritol.

6. The method for preparing emulsion wet spinning according to claim 1, characterized in that, In step (7), the conductive polymer solution is one or more of PEDOT:PSS / DMSO, PEDOT:PSS / DMF, polyaniline solution, and polypyrrole nanodispersion in any proportion, the concentration of the conductive polymer solution is 60~80 wt.%, and the impregnation time is 10 min~1 h.

7. The method for preparing emulsion wet spinning according to any one of claims 1 to 6, characterized in that, The processing temperature in step (2) is 20~50 ℃, the ultrasonic power is 100~350 W, and the ultrasonic time is 2~4 h; the stirring time in step (3) is 1~3 h; the temperature of shear emulsification in step (4) is 26~280 ℃, and the time is 2~4 h.

8. The method for preparing emulsion wet spinning according to claim 1, characterized in that, The coagulation bath temperature during the spinning process is 0~40 ℃.

9. A phase change synergistic thermoelectric fiber prepared by the emulsion wet spinning method according to any one of claims 1 to 8.

10. The application of the phase change synergistic thermoelectric fiber as described in claim 9 in wearable devices, smart textile equipment, and smart clothing.

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