A carbon nanotube and polyaniline flexible composite thermoelectric fiber and its preparation method and application

Abstract

The present invention belongs to the technical field of organic thermoelectric materials, and specifically relates to a flexible composite thermoelectric fiber of carbon nanotubes and polyaniline, and its preparation method and application. The method comprises the following steps: 1) mixing aniline with single-walled carbon nanotubes, and subjecting the aniline to in-situ chemical oxidation polymerization to obtain a mixture of intrinsic polyaniline and single-walled carbon nanotubes; 2) doping the mixture obtained in step 1) with camphorsulfonic acid to obtain a doped mixture; 3) preparing the doped mixture obtained in step 2) into a spinning solution, and subjecting it to wet spinning to obtain a flexible composite thermoelectric fiber of carbon nanotubes and polyaniline. Compared with existing thermoelectric film materials, the flexible composite thermoelectric fiber material provided by the present invention has the advantages of good air permeability, easy integration with fabrics while maintaining beauty and comfort, and has irreplaceable advantages in the field of wearable thermoelectric devices.

Description

Technical Field

[0001] The present invention belongs to the technical field of organic thermoelectric materials, and in particular relates to a carbon nanotube and polyaniline flexible composite thermoelectric fiber, and a preparation method and application thereof. Background Art

[0002] With the widespread adoption of flexible electronics in portable and wearable applications, technologies for sustained and reliable self-powered devices are rapidly developing. Research has found that approximately 70% of energy in our daily lives is consumed as waste heat. Consequently, thermoelectric devices, which can convert heat into electricity and vice versa, are attracting increasing attention. Organic thermoelectric devices offer advantages such as noiselessness, pollution-free operation, vibration-free operation, and long lifespan. Flexible thermoelectric devices developed based on this principle utilize the temperature difference between the skin and the surrounding environment to generate a thermoelectric potential. This, when connected to an external circuit, generates an electric current, thereby charging an internal battery or supercapacitor.

[0003] The performance of thermoelectric materials is usually evaluated by the dimensionless figure of merit: ZT = S 2 σT / κ, where S, σ, κ and T are the Seebeck coefficient, electrical conductivity and thermal conductivity and absolute temperature of the material respectively. Since the thermal conductivity of polymers is generally low and has little variation, the power factor PF = S 2 σ is also often used to evaluate the thermoelectric performance of materials. Conductive polymers, including poly(3,4-ethylenedioxythiophene) (PEDOT), polyaniline (PANI), and polypyrrole (PPy), have attracted a large number of researchers due to their good mechanical flexibility and high thermoelectric conversion efficiency. Compared with traditional inorganic thermoelectric materials, conductive polymers are more suitable for flexible electronic devices due to their flexibility, light weight, non-toxicity, pollution-free, and low cost. However, due to the low electrical conductivity and Seebeck coefficient of conductive polymers, it is extremely important to improve their thermoelectric performance by combining them with inorganic materials with high conductivity and Seebeck coefficient, such as Bi2Te3 / PEDOT, CNTs / PANI, Te / CNTs / PEDOT, etc.

[0004] Currently, research on polyaniline thermoelectrics is often limited to thin films. Thin films, due to their thin thickness and poor air permeability, hinder the processing, preparation, and application of devices. Compared to thin films, fibers offer advantages such as excellent air permeability and ease of integration with fabrics, maintaining aesthetics and comfort. This patent successfully produces flexible CNTs / PANI organic composite fibers by adjusting wet spinning parameters. The fibers also enhance their thermoelectric performance through optimized spinning process control, demonstrating significant potential in the fields of flexible wearables and microelectronics. Summary of the Invention

[0005] In order to address the deficiencies of the prior art, the present invention provides a carbon nanotube and polyaniline flexible composite thermoelectric fiber, and a preparation method and application thereof.

[0006] The technical solutions provided by the present invention are as follows:

[0007] A method for preparing a flexible composite thermoelectric fiber of carbon nanotubes and polyaniline comprises the following steps:

[0008] 1) mixing aniline with single-walled carbon nanotubes, and subjecting the aniline to in-situ chemical oxidative polymerization to obtain a mixture of intrinsic polyaniline and single-walled carbon nanotubes;

[0009] 2) doping the mixture obtained in step 1) with camphorsulfonic acid to obtain a doped mixture;

[0010] 3) The doped mixture obtained in step 2) is prepared into a spinning solution, and wet spinning is performed to prepare a flexible composite thermoelectric fiber of carbon nanotubes and polyaniline.

[0011] In the above technical solution:

[0012] Based on step 1) and step 2), the obtained doped material is ensured to have high thermoelectric properties and good mechanical properties after spinning;

[0013] The flexible composite thermoelectric fiber material obtained based on step 3) has the advantages of good air permeability, easy integration with fabrics while maintaining beauty and comfort compared to existing thermoelectric film materials, and has irreplaceable advantages in the field of wearable thermoelectric devices.

[0014] Specifically, in step 3), the spinning solution is transferred into a syringe, and extruded into a coagulation bath at a constant rate under the pressure of a pump to form a flexible composite thermoelectric fiber of carbon nanotubes and polyaniline.

[0015] Specifically, the size of the syringe needle is 21 to 30G.

[0016] Specifically, the rate of extrusion from the syringe is 0.05 to 0.5 mL / min.

[0017] Specifically, in the spinning solution, the solute is the doped mixture obtained in step 2), and the solvent is m-cresol.

[0018] Specifically, the concentration of the spinning solution is 10 to 20 mg / mL.

[0019] Specifically, the spinning solution is extruded into an ethanol solution for immersion to form the solution, and then taken out and transferred to a hot plate for drying to obtain a flexible composite thermoelectric fiber of carbon nanotubes and polyaniline.

[0020] Specifically, the soaking time is 1 minute to 25 hours; and the soaking temperature is 0 to 25°C.

[0021] Specifically, the weight ratio of the single-walled carbon nanotubes to the flexible composite thermoelectric fibers is 0 to 85 wt %.

[0022] The present invention also provides a carbon nanotube and polyaniline flexible composite thermoelectric fiber prepared by the above preparation method.

[0023] The carbon nanotube and polyaniline flexible composite thermoelectric fiber provided by the present invention has high thermoelectric performance and good mechanical properties.

[0024] The present invention also provides an application of the above-mentioned carbon nanotube and polyaniline flexible composite thermoelectric fiber as a flexible wearable device fiber material, or as a microelectronic flexible fiber material.

[0025] The carbon nanotube and polyaniline flexible composite thermoelectric fiber provided by this invention has high thermoelectric performance and good mechanical properties, making it suitable for use in flexible wearable devices or microelectronics. Furthermore, because it is a fiber material, it offers significant advantages over existing thermoelectric thin film materials, such as improved air permeability and ease of integration with fabrics while maintaining aesthetics and comfort. It could potentially replace thermoelectric thin film materials.

[0026] Compared with the prior art, the present invention has the following advantages:

[0027] 1) The preparation process of the present invention is simple, low-cost, highly controllable, and has excellent stability, and is suitable for large-scale industrial production of organic composite thermoelectric materials;

[0028] 2) The coagulation bath used was a green and clean ethanol solution. Taking advantage of the principle that the solvent m-cresol is miscible with ethanol, while PANI and CNTs are insoluble in ethanol solution, CNTs / PANI composite fibers were successfully prepared under the action of double diffusion.

[0029] 3) The fiber can be bent repeatedly, has good flexibility, and can fit the skin surface for use in wearable applications.

[0030] 4) The thermoelectric properties of the fiber were tested, and the results showed that the CNTs / PANI composite fiber has high thermoelectric properties. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 These are microscope images of the CNTs / PANI fibers provided by the present invention, wherein (a) is a microscope image of 45 wt% CNTs / PANI fibers, and (b) is a microscope image of 70 wt% CNTs / PANI fibers.

[0032] Figure 2 It is the thermoelectric performance of CNTs / PANI fiber with different CNTs contents in the present invention.

[0033] Figure 3The thermoelectric properties of 45wt% CNTs / PANI fibers under different immersion times of the present invention. DETAILED DESCRIPTION

[0034] The principles and features of the present invention are described below. The examples given are only used to explain the present invention and are not used to limit the scope of the present invention.

[0035] Example 1:

[0036] Carbon nanotube (CNTs) and polyaniline (PANI) composite powder was prepared by in-situ oxidative polymerization. The powder was added to 0.1 mol / L ammonia solution and stirred for dedoping. After filtration, washing with water, and vacuum drying at 60°C, carbon nanotube and intrinsic polyaniline powder was obtained, wherein the carbon nanotube content was 45wt%. An appropriate amount of carbon nanotube and intrinsic polyaniline powder was taken, and camphorsulfonic acid was added to it at a molar ratio of aniline to camphorsulfonic acid of 2:1 for secondary doping. The powder was dispersed in m-cresol solvent and stirred to obtain a spinning solution with a concentration of 20 mg / mL. The spinning solution was transferred to a 25G injection and squeezed into a cold ethanol solution at a rate of 0.2 mL / min using a syringe pump. The solution was immersed in ethanol for 1 minute and solidified into a shape. After removal, the solution was transferred to a hot plate and dried for 5 hours to obtain a flexible CNTs / PANI composite fiber. The thermoelectric performance test showed that the conductivity was 896 S cm -1 , the Seebeck coefficient is 24μV K -1 , the power factor is 51μW m -1 K -2 .

[0037] Example 2:

[0038] The same as Example 1, except that the spinning solution was squeezed into a cold ethanol solution and soaked for 30 minutes, then transferred to a hot plate and dried for 5 hours to obtain a flexible CNTs / PANI composite fiber. The thermoelectric performance test showed that the conductivity was 206Scm -1 , the Seebeck coefficient is 42μV K -1 , the power factor is 36μW m -1 K -2 .

[0039] Example 3:

[0040] The same as Example 1, except that the spinning solution was squeezed into a cold ethanol solution and soaked for 25 hours, then transferred to a hot plate and dried for 5 hours to obtain a flexible CNTs / PANI composite fiber. The thermoelectric performance test showed that the conductivity was 90S cm -1 , the Seebeck coefficient is 46μV K -1 , power factor is 19μWm -1 K -2 .

[0041] It can be seen from Examples 1 to 3 that, for the preparation of flexible CNTs / PANI composite fibers, an increase in the immersion time leads to a significant decrease in the electrical conductivity and power factor, and a significant increase in the Beck coefficient.

[0042] Example 4:

[0043] The same as Example 1, except that pure PANI fiber was prepared. Polyaniline and camphorsulfonic acid were added to camphorsulfonic acid in a molar ratio of 2:1 for secondary doping, and the mixture was dispersed in m-cresol solvent and stirred to obtain a spinning solution of pure PANI solution. The spinning solution was squeezed into a cold ethanol solution and soaked for 1 minute, extruded at a rate of 0.1 mL / min, and then transferred to a hot plate for drying for 5 hours to obtain flexible PANI fiber. The final conductivity was 127 S cm -1 , the Seebeck coefficient is 14μV K -1 , the power factor is 2.4μW m -1 K -2 .

[0044] Example 5:

[0045] The same as Example 4, except that pure PANI fiber was prepared, the spinning solution was squeezed into a cold ethanol solution and soaked for 30 minutes, and then dried on a hot plate for 5 hours to obtain flexible PANI fiber. The final conductivity was 20S cm -1 , the Seebeck coefficient is 18μVK -1 , the power factor is 0.6μW m -1 K -2 .

[0046] Example 6:

[0047] The same as Example 4, except that the spinning solution was squeezed into a cold ethanol solution and soaked for 25 hours, and then baked on a hot plate for 5 hours to obtain the flexible PANI fiber. The final conductivity was 4S cm -1 , the Seebeck coefficient is 24μV K -1 , the power factor can reach 0.2μW m -1 K -2 .

[0048] It can be seen from Examples 4 to 6 that without adding carbon nanotubes, the electrical conductivity and power factor are lower.

[0049] Example 7:

[0050] The same as Example 1, except that an organic composite fiber with a CNT content of 80 wt% was prepared. The spinning solution was squeezed into a cold ethanol solution and soaked for 1 minute, and then baked on a hot plate for 5 hours to obtain a flexible CNTs / PANI composite fiber. The final conductivity was 864 S cm -1 , the Seebeck coefficient is 31μV K -1 , the power factor can reach 83μW m -1 K -2 .

[0051] It can be seen from Example 7 that increasing the carbon nanotube content significantly improves the conductivity, increases the Seebeck coefficient, and leads to an increase in the power factor.

[0052] Example 8:

[0053] The same as Example 7, except that the needle type was adjusted to 21G, the spinning solution was squeezed into the cold ethanol solution and soaked for 1 minute, and then baked on a hot plate for 5 hours to obtain the flexible CNTs / PANI composite fiber. The final conductivity was 1340S cm -1 , the Seebeck coefficient is 27μV K -1 , the power factor can reach 97μW m -1 K -2 .

[0054] It can be seen from Example 8 that, when the material composition remains unchanged, the electrical conductivity and power factor of the fiber material can be further significantly improved.

[0055] Example 9:

[0056] The same as Example 7, except that the needle type was adjusted to 30G, the spinning solution was squeezed into the cold ethanol solution and soaked for 1 minute, and then baked on a hot plate for 5 hours to obtain the flexible CNTs / PANI composite fiber. The final conductivity was 670S cm -1 , the Seebeck coefficient is 32μV K -1 , the power factor can reach 69μW m -1 K -2 .

[0057] It can be seen from Examples 8 and 9 that the thermoelectric performance can be controlled by adjusting the needle model.

[0058] Example 10:

[0059] The same as Example 1, except that an organic composite fiber with a CNT content of 85 wt% was prepared. The spinning solution was squeezed into a cold ethanol solution and soaked for 30 minutes, and then baked on a hot plate for 5 hours to obtain a flexible CNTs / PANI composite fiber. The final conductivity was 400 S cm -1 , the Seebeck coefficient is 42μV K-1 , the power factor can reach 71μW m -1 K -2 .

[0060] Example 11:

[0061] The same as Example 1, except that the spinning solution concentration was 10 mg / mL. The spinning solution was squeezed into a cold ethanol solution and soaked for 25 hours, and then baked on a hot plate for 5 hours to obtain a flexible CNTs / PANI composite fiber. The final conductivity was 71 S cm -1 , the Seebeck coefficient is 48μV K -1 , the power factor can reach 16μW m -1 K -2 .

[0062] It can be seen from Examples 10 and 11 that the immersion time has a direct impact on the doping degree, which affects the electrical conductivity and the Seebeck coefficient. Therefore, the immersion time has an important influence on the thermoelectric performance.

[0063] Example 12:

[0064] The same as Example 1, except that the syringe extrusion rate was 0.05 mL / min. The spinning solution was squeezed into a cold ethanol solution and soaked for 1 minute, and then baked on a hot plate for 5 hours to obtain a flexible CNTs / PANI composite fiber. The final conductivity was 941 Scm -1 , the Seebeck coefficient is 24μV K -1 , the power factor can reach 54μW m -1 K -2 .

[0065] Example 13:

[0066] The same as Example 1, except that the syringe extrusion rate was 0.5 mL / min. The spinning solution was squeezed into a cold ethanol solution and soaked for 1 minute, and then baked on a hot plate for 5 hours to obtain a flexible CNTs / PANI composite fiber. The final conductivity was 481 Scm -1 , the Seebeck coefficient is 32μV K -1 , the power factor can reach 49μW m -1 K -2 .

[0067] It can be seen from Examples 12 and 13 that the power factor can be adjusted by changing the extrusion speed.

[0068] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A method for preparing a flexible composite thermoelectric fiber of carbon nanotubes and polyaniline, characterized in that: The specific steps are as follows: 1) mixing aniline with single-walled carbon nanotubes, and subjecting the aniline to in-situ chemical oxidative polymerization to obtain a mixture of intrinsic polyaniline and single-walled carbon nanotubes; 2) doping the mixture obtained in step 1) with camphorsulfonic acid to obtain a doped mixture; 3) The doped mixture obtained in step 2) is prepared into a spinning solution and wet-spinned, the spinning solution is extruded into an ethanol solution for immersion, formed, taken out and transferred to a hot plate for drying to prepare a carbon nanotube and polyaniline flexible composite thermoelectric fiber; in the spinning solution, the solute is the doped mixture obtained in step 2) and the solvent is m-cresol.

2. The method for preparing the carbon nanotube and polyaniline flexible composite thermoelectric fiber according to claim 1, characterized in that: In step 3), the spinning solution is transferred into a syringe, and extruded into a coagulation bath at a constant rate under the pressure of a pump to form a flexible composite thermoelectric fiber of carbon nanotubes and polyaniline.

3. The method for preparing the carbon nanotube and polyaniline flexible composite thermoelectric fiber according to claim 2, characterized in that: The size of the syringe needle is 21 to 30G; The rate of extrusion from the syringe is 0.05 to 0.5 mL / min.

4. The method for preparing the carbon nanotube and polyaniline flexible composite thermoelectric fiber according to claim 3, characterized in that: The concentration of the spinning solution is 10-20 mg / mL.

5. The method for preparing the carbon nanotube and polyaniline flexible composite thermoelectric fiber according to claim 2, characterized in that: The soaking time is 1 minute to 25 hours; the soaking temperature is 0 to 25°C.

6. The method for preparing the carbon nanotube and polyaniline flexible composite thermoelectric fiber according to any one of claims 1 to 5, characterized in that: The weight ratio of the single-walled carbon nanotube to the flexible composite thermoelectric fiber is 0-85wt%.

7. A flexible composite thermoelectric fiber of carbon nanotubes and polyaniline prepared according to the preparation method according to any one of claims 1 to 6.

8. An application of the flexible composite thermoelectric fiber according to claim 7, characterized in that: As a fiber material for flexible wearable devices; Alternatively, as a flexible fiber material for microelectronics.

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