CN116288797A

CN116288797A - Flexible PEDOT (polyether-ether-ketone) PSS (power supply system) conductive composite fiber and preparation method thereof

Info

Publication number: CN116288797A
Application number: CN202310265854.1A
Authority: CN
Inventors: 丛洪莲; 赵树强; 蒋高明; 贺海军; 万爱兰
Original assignee: Jiangnan University
Current assignee: Jiangnan University
Priority date: 2023-03-17
Filing date: 2023-03-17
Publication date: 2023-06-23

Abstract

The application relates to a flexible PEDOT (polyether-ether-ketone) PSS conductive composite fiber and a preparation method thereof, and relates to the field of conductive fibers. The introduction of the fiber-forming polymer insulating material in the wet-spun PEDOT-PSS conductive composite fiber prepared by the existing method causes the PEDOT chain segments to be difficult to aggregate and disperse uniformly, so that the conductive performance of the PEDOT chain segments is influenced, the conductive materials with different dimensions are required to be integrated effectively, the synergistic effect among the different materials is exerted, the conductive performance of the PEDOT-PSS conductive composite fiber is further improved, and the tensile strength of the PEDOT-PSS conductive composite fiber is improved. In order to solve the problems, the application uses the TPU modified by gallic acid or derivatives thereof and hexamethylenediamine as a matrix, adopts a valence bond crosslinking strategy, and effectively integrates PEDOT, carbon nanotubes and derivatives thereof, MXene and derivatives thereof with metal nano silver particles to construct a multidimensional conductive network. Solves the problems of poor dispersion and easy agglomeration of PEDOT in the conductive fiber, and solves the problem that the conductivity and high strength of the conventional PEDOT-PSS conductive composite fiber are difficult to combine.

Description

Flexible PEDOT (polyether-ether-ketone) PSS (power supply system) conductive composite fiber and preparation method thereof

Technical Field

The application relates to the technical field of conductive fibers, in particular to a flexible PEDOT (polyethylene terephthalate) PSS conductive composite fiber and a preparation method thereof.

Background

In recent years, intelligent fibers and textiles are sought after by extensive research teams, and conductive fibers based on conductive polymers become an important intelligent fiber with good application prospect due to good electromagnetic shielding and antistatic properties and flexible characteristics of the polymers. In the method for preparing the conductive fiber, the wet spinning preparation of the conductive fiber is simple to operate, can realize industrial production, and has good application prospect. In particular to poly 3, 4-ethylenedioxythiophene (PEDOT) fiber which has the advantages of high conductivity, good stability, good optical transparency and the like, but is an insoluble polymer, so that the processing is difficult and the application of the polymer is limited. After the PEDOT is doped with polystyrene sulfonic acid (PSS), a stable PEDOT-PSS aqueous dispersion liquid which is uniformly dispersed can be obtained, and the problem of difficult PEDOT processing is solved. Under certain conditions, the continuous fiber can be prepared by a simple wet spinning technology, and the method has wide application prospects in the aspects of intelligent fabrics, wearable electronic equipment and the like. For example: pure spun PEDOT: PSS fibers (OKUZAKI H, ISHIHAR A M.spinning and characterization of conducting micro fibers. Macromolecular Rapid Communications [ J ],2003,24 (3): 261-264.) with conductivities of about 0.1S/cm were prepared from the At-IPA coagulation bath system of OKUZAKI et al; PEDOT: PSS fibers wet spun using the novel aqueous-alcoholic coagulation bath employed by Yuan et al, have an electrical conductivity of 38S/cm after treatment with EG (Yuan D, LI B, CHENG J, et al, twisted yarns for fiber-shaped supercapacitors based on wetspun PEDOT: PSS fibers from aqueous coagulation [ J ]. Journal of Materials Chemistry A,2016,4 (30): 11616-11624). In addition, patent (CN 106381571A) mentions a PEDOT: PSS fiber and a preparation method thereof, wherein the patent uses a mixed solution of inorganic salt, ethanol and water as a coagulating bath, and wet spinning PEDOT: PSS fiber with the conductivity of 400-850S/cm is prepared by a simple chemical treatment method.

However, the PEDOT: PSS fibers disclosed in the related art still have some problems: firstly, PEDOT, PSS aqueous dispersion has low solid content and low viscosity, is difficult to directly carry out wet spinning, is not easy to operate, and the fiber is often broken in a coagulating bath or air, so that continuous fiber filaments are not easy to obtain; secondly, the PEDOT has high rigidity of the molecular chain due to the existence of the conjugate structure of the PEDOT molecular chain, so that the prepared PEDOT-PSS pure spinning fiber has high brittleness, high rigidity, poor toughness and poor mechanical property, and is not suitable for subsequent processing and application. In order to solve the problems, researchers use fiber-forming polymer materials to blend with PEDOT: PSS, and prepare composite conductive PEDOT: PSS fibers by wet spinning. PSS fibers (Seyedin, S.; razal, J.M.; innis, P.C.; jeiranikhamen, A.; beirne, S.; wallace, G.G.Knitted Strain Sensor Textiles of Highly Conductive All-Polymer fibers.ACS appl. Mater. Interfaces 2015,7,21150-21158.) were developed using wet spinning by Seyedin et al. However, the introduction of the fiber-forming polymer material may reduce the dispersion of the PEDOT: PSS, while the conductive PEDOT segment is embedded in the insulating PSS, which hinders efficient aggregation of the PEDOT segment, and makes it difficult to form a conductive continuous phase, thereby limiting the conductivity of the conductive composite fiber. Therefore, how to prepare fibers with strong continuity, high strength and good conductivity by a simple method is a problem to be solved.

Disclosure of Invention

The invention aims to provide a flexible PEDOT (polyether-ether-ketone) PSS conductive composite fiber and a preparation method thereof, which are used for solving the problem that the conductive performance of the wet spinning PEDOT (polyether-ether-ketone) PSS conductive composite fiber is affected due to the fact that PEDOT chain segments are difficult to aggregate and disperse uniformly caused by the introduction of a fiber forming polymer insulating material in the wet spinning PEDOT PSS conductive composite fiber prepared by the existing method.

In order to achieve the above purpose, the technical scheme adopted in the application is as follows:

in one aspect, the application provides a method for preparing a flexible PEDOT: PSS conductive composite fiber, which comprises the following steps:

s1, adding TPU into DMF solution, and stirring by using a constant-temperature magnetic stirrer to obtain TPU spinning solution;

s2, adding PEDOT PSS into a mixed solution containing gallic acid or derivatives thereof, hexamethylenediamine and Tris buffer solution, and stirring by using a constant-temperature magnetic stirrer to obtain a PEDOT PSS mixed solution;

s3, sequentially adding CNTs-DMPA, MXene and silver powder into the PEDOT-PSS mixed solution, and stirring by using a constant-temperature magnetic stirrer to obtain the PEDOT-PSS mixed conductive solution;

s4, slowly pouring the PEDOT-PSS mixed conductive solution into the TPU spinning stock solution, and stirring by using a constant-temperature magnetic stirrer to obtain the PEDOT-PSS mixed spinning solution;

s5, injecting the PEDOT and PSS mixed spinning solution into an injector, carrying out wet spinning at normal temperature, extruding the PEDOT and PSS mixed spinning solution into DMF aqueous coagulating bath by using an injection pump, carrying out three times of mechanical drawing on primary fibers coagulated and molded by the coagulating bath, carrying out heat setting treatment, and finally winding the fibers subjected to heat setting treatment on a heat roller rotating at a constant speed for collection and drying to obtain the flexible PEDOT and PSS conductive composite fibers.

In one possible implementation manner, in the step S1:

the content of the TPU is 2-10g/L;

the mass volume concentration of the DMF is 20-200mg/mL;

the constant temperature of the constant temperature magnetic stirrer is 40-60 ℃, the stirring speed is 200-660rpm, and the stirring time is 4-10h.

In one possible implementation manner, in the step S2:

the concentration of PEDOT and PSS is 10-60mol/L;

the concentration of the gallic acid or the derivative thereof is 15-45mol/L;

the concentration of the hexamethylenediamine is 15-65mol/L;

the concentration of the Tris buffer solution is 0.5-4.5mol/L.

In one possible implementation manner, in the step S2:

the pH value of the solution obtained by adding PEDOT PSS into the mixed solution containing gallic acid or the derivative thereof, hexamethylenediamine and Tris buffer solution is 8-10;

the constant temperature of the constant temperature magnetic stirrer is 40-60 ℃, the stirring speed is 200-660rpm, and the stirring time is 10-40min.

In one possible implementation manner, in the step S2:

the gallic acid or the derivative thereof comprises one of pyrogallic acid, gallic acid, (Z) -3,4,5,4', -tetramethoxy-3' -hydroxystyrene and GA butyl ester.

In one possible implementation manner, in the step S3:

the concentration of the CNTs-DMPA, the MXene and the silver powder is 5-10mol/L, 2-6mol/L and 4-15mol/L respectively.

In one possible implementation manner, in the step S3:

the constant temperature of the constant temperature magnetic stirrer is 40-60 ℃;

the initial stirring speed of the constant temperature magnetic stirrer is set to be 200-600rpm, and stirring is continuously carried out for 0.5-4.5h; then the stirring speed is adjusted to 500-800rpm, and stirring is continued for 10-60min; finally, the stirring speed is adjusted to 900-2500rpm, and stirring is continued for 4-12h.

In one possible implementation manner, in the step S4:

the constant temperature of the constant temperature magnetic stirrer is 40-60 ℃, the stirring speed is 200-660rpm, and the stirring time is 2-12h.

In one possible implementation manner, in the step S5:

the volume capacity of the injector is 5-40mL, and the inner diameter of the needle head is 0.2-0.8mm;

the spinning speed of the wet spinning is 0.5-6.5mL/h;

the length of the coagulating bath is 90cm;

the temperature of the heat setting treatment is 60 ℃;

and winding the fiber subjected to heat setting treatment on a heat roller rotating at a constant speed, wherein the drying temperature in the process of collecting and drying is 20-40 ℃, and the drying time is 6-12h.

On the other hand, the application also provides the flexible PEDOT-PSS conductive composite fiber, which is prepared by the preparation method of the flexible PEDOT-PSS conductive composite fiber.

The beneficial effects that this application provided technical scheme brought include at least:

(1) The flexible PEDOT-PSS conductive composite fiber takes gallic acid or derivatives thereof and TPU modified by hexamethylenediamine function as a matrix, and a multidimensional conductive network is constructed in the matrix by utilizing a valence bond crosslinking strategy; the functional modification of the gallic acid or the derivative thereof and the hexamethylenediamine means that the gallic acid or the derivative thereof and the amino and phenolic hydroxyl groups in the hexamethylenediamine realize the high-phase separation of PSS and PEDOT through hydrogen bond association on one hand, optimize the conformation of a PEDOT molecular chain, enable the PEDOT to form an orderly arranged conductor continuous phase, and bond with TPU through coordination, electrostatic interaction, hydrophobic interaction and even covalent reaction on the other hand; the valence bond crosslinking strategy refers to a process of obtaining a stable conductive network structure through dynamic valence bond crosslinking among different substances; the multidimensional conductive network structure refers to: on the one hand, the two-dimensional conductive network structure between PEDOT and silver nano particles, and on the other hand, the three-dimensional conductive network structure between MXene or derivatives thereof and carbon nano tubes or derivatives thereof and silver nano particles.

(2) Compared with the prior art, the method for preparing the fiber has the advantages of simple equipment, simple spinning process, environment friendliness, remarkable effect improvement, no need of expensive and complex equipment, easy realization of mass production, and good softness, tensile property and large-scale integration property, and can be widely applied to wearable devices.

(3) The conductive composite fiber prepared by adopting the valence bond crosslinking strategy solves the problems of poor dispersibility and easy aggregation of PEDOT, and simultaneously, the crosslinking of the carbon nano tube and the derivative thereof, the MXene and the derivative thereof and the metal nano silver particles further improves the continuity and controllability of the three-dimensional conductive network structure, so that the conductive filler can be uniformly dispersed, the raw materials are saved, the conductivity and the structural stability of the composite material are improved, and a new thought is provided for the development of new conductive fibers.

(4) The PEDOT prepared by the method has the tensile strength of PSS conductive composite fiber of 780.62MPa and strain of 1204.28 percent, and the conductivity of the PEDOT conductive composite fiber is within 2369-2405S/cm after 650 times of friction; after 240 water washes, the conductivity is within 2365-2405S/cm.

Drawings

The accompanying drawings are included to provide a further understanding of the application and are incorporated in and constitute a part of this specification, illustrate the application and together with the embodiments of the application, and not constitute a limitation to the application. In the drawings:

FIG. 1 shows a flow chart of a method of preparing a flexible PEDOT: PSS conductive composite fiber provided in one exemplary embodiment of the present application;

FIG. 2 shows an electron microscope image of a flexible PEDOT: PSS conductive composite fiber provided in one exemplary embodiment of the present application;

fig. 3 shows gallic acid or derivatives thereof doped with hexamethylenediamine versus PEDOT: schematic diagram of the mechanism of action of the PSS chemical structure;

figure 4 shows a schematic diagram of the synthetic mechanism and chemical structure between a PEDOT conductive composite and a TPU functionally modified with gallic acid or its derivatives.

Detailed Description

The following description of the embodiments of the present application will be made clearly and fully with reference to the accompanying drawings, in which it is evident that the embodiments described are only some, but not all, of the embodiments of the present application. All other embodiments, which can be made by one of ordinary skill in the art without undue burden from the present disclosure, are within the scope of the present disclosure.

Wherein like parts are designated by like reference numerals. It should be noted that the words "front", "rear", "left", "right", "upper" and "lower" used in the following description refer to directions in drawings of the present specification, and the words "bottom" and "top", "inner" and "outer" refer to directions toward or away from, respectively, a specific component. Furthermore, the terms "first," "second," and the like, are used for descriptive purposes only and are not to be construed as indicating or implying a relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defining "a first" or "a second" may explicitly or implicitly include one or more such feature. In the description of the present specification, the meaning of "plurality" is two or more.

The present application is further described below with reference to the drawings and examples.

First, the terms involved in the embodiments of the present application will be briefly described:

TPU is a short name of Thermoplastic Urethane, the Chinese name is thermoplastic polyurethane elastomer, and the TPU is a high polymer material formed by the joint reaction polymerization of diphenylmethane diisocyanate (MDI), toluene Diisocyanate (TDI), macromolecular polyol and a chain extender.

DMF, dimethylformamide (DMF or N, N-dimethylformamide) is a transparent liquid which is miscible with water and most organic solvents and is a common solvent for chemical reactions.

Tris buffer solution refers to Tris-HCl (Tris hydrochloride buffer solution), and is specifically obtained by mixing Tris (Tris) solution with hydrochloric acid uniformly and then adding water for dilution.

CNTs-DMPA, wherein carboxylated CNTs are prepared by the reaction of thionyl chloride (SOCl) ₂ ) And after surface modification of Triethylamine (TEA), crosslinking 2, 2-dimethylolpropionic acid (DMPA) to obtain CNTs-DMPA.

Carboxylation CNTs are obtained by placing carbon nanotubes into a mixed acid solution of concentrated sulfuric acid and concentrated nitric acid for etching ultrasonic treatment, and then placing the carbon nanotubes at 70-80 ℃ for stirring.

The method comprises the steps of (1) esterifying and modifying GA by using concentrated sulfuric acid as a catalyst and n-butanol as a modifier to obtain GA butyl ester, wherein Gallic Acid (GA) is a natural phenolic compound containing three hydroxyl groups, and is prepared by extracting polyphenol crude extract of fruits, nuts, flowers and the like; one of the remarkable characteristics of natural polyphenols is antioxidant activity; thus, GA has a significant feature of oxidation resistance; three phenolic hydroxyl groups in the GA molecular structure can be used as hydrogen atom acceptors to effectively absorb free hydrogen ions; and GA contains certain antibacterial property and antiviral property, and polyphenol compounds such as GA have remarkable antibacterial property compared with diphenol compounds; their antimicrobial properties are manifested in a number of ways, such as inhibition of nucleic acid production; promoting cytoplasmic membrane dysfunction or counteracting energy required for metabolism; based on many excellent properties of GA, GA is widely used in the fields of medicine, organic synthesis, cosmetics, etc.; GA is a phenolic natural compound containing three hydroxyl groups, is also called gallic acid, is widely existing in plants such as rheum palmatum, ammonium macrophylla and the like, and is a naturally generated polyphenol containing three hydroxyl groups; because the molecular structure of the polyurethane contains three phenolic hydroxyl groups and one carboxyl group, and the phenolic hydroxyl groups can provide active hydrogen to react with-NCO, the polyurethane can be used for preparing bio-based crosslinking polyurethane.

Fig. 1 shows a flowchart of a method for preparing a flexible PEDOT: PSS conductive composite fiber according to an exemplary embodiment of the present application, the method comprising the steps of:

and S1, adding the TPU into the DMF solution, and stirring by using a constant-temperature magnetic stirrer to obtain the TPU spinning solution.

In step S1 of this embodiment, the TPU content is 2-10g/L; the mass volume concentration of DMF is 20-200mg/mL; the constant temperature of the constant temperature magnetic stirrer is 40-60 ℃, the stirring speed is 200-660rpm, and the stirring time is 4-10h.

And S2, adding PEDOT/PSS into a mixed solution containing gallic acid or derivatives thereof, hexamethylenediamine and Tris buffer solution, and stirring by using a constant-temperature magnetic stirrer to obtain the PEDOT/PSS mixed solution.

In the step S2 of the embodiment, the concentration of PEDOT to PSS is 10-60mol/L; the concentration of gallic acid or its derivative is 15-45mol/L; the concentration of the hexamethylenediamine is 15-65mol/L; the concentration of Tris buffer is 0.5-4.5mol/L. Specifically, the pH of the solution obtained by adding PEDOT: PSS to a mixed solution containing gallic acid or a derivative thereof, hexamethylenediamine and Tris buffer is 8-10; the constant temperature of the constant temperature magnetic stirrer is 40-60 ℃, the stirring speed is 200-660rpm, and the stirring time is 10-40min. Optionally, the gallic acid or the derivative thereof comprises one of pyrogallic acid, gallic acid, (Z) -3,4,5,4', -tetramethoxy-3' -hydroxy stilbene (Combretastatin A-4) and GA butyl ester.

And step S3, sequentially adding CNTs-DMPA, MXene and silver powder into the PEDOT-PSS mixed solution, and stirring by using a constant-temperature magnetic stirrer to obtain the PEDOT-PSS mixed conductive solution.

In step S3 of this example, the concentrations of CNTs-DMPA, MXene and silver powder were 5-10mol/L, 2-6mol/L and 4-15mol/L, respectively. In addition, the constant temperature of the constant temperature magnetic stirrer is 40-60 ℃; the initial stirring speed of the constant temperature magnetic stirrer is set to be 200-600rpm, and stirring is continuously carried out for 0.5-4.5h; then the stirring speed is adjusted to 500-800rpm, and stirring is continued for 10-60min; finally, the stirring speed is adjusted to 900-2500rpm, and stirring is continued for 4-12h.

And S4, slowly pouring the PEDOT/PSS mixed conductive solution into the TPU spinning solution, and stirring by using a constant-temperature magnetic stirrer to obtain the PEDOT/PSS mixed spinning solution.

In step S4 of this embodiment, the constant temperature of the constant temperature magnetic stirrer is 40-60 ℃, the stirring speed is 200-660rpm, and the stirring time is 2-12h.

And S5, injecting the PEDOT-PSS mixed spinning solution into an injector, carrying out wet spinning at normal temperature, extruding the PEDOT-PSS mixed spinning solution into DMF aqueous coagulating bath by using an injection pump, carrying out three times of mechanical drawing on primary fibers coagulated and molded by the coagulating bath, carrying out heat setting treatment, and finally winding the fibers subjected to the heat setting treatment on a heat roller rotating at a constant speed for collection and drying to obtain the flexible PEDOT-PSS conductive composite fibers.

In step S5 of the embodiment, the volume capacity of the syringe is 5-40mL, and the inner diameter of the needle is 0.2-0.8mm; the spinning speed of wet spinning is 0.5-6.5mL/h; the length of the coagulation bath is 90cm; the heat setting treatment temperature was 60 ℃. In addition, winding the fiber after heat setting treatment on a heat roller rotating at a constant speed, and collecting and drying at 20-40 ℃ for 6-12h.

Fig. 2 shows an electron microscope image of a flexible PEDOT: PSS conductive composite fiber according to an exemplary embodiment of the present application, which is prepared by the above-described preparation method of the flexible PEDOT: PSS conductive composite fiber.

In summary, the flexible PEDOT-PSS conductive composite fiber takes gallic acid or derivatives thereof and TPU modified by hexamethylenediamine function as a matrix, and a multidimensional conductive network is constructed in the matrix by utilizing a valence bond crosslinking strategy; the functional modification of the gallic acid or the derivative thereof and the hexamethylenediamine means that the gallic acid or the derivative thereof and the amino and phenolic hydroxyl groups in the hexamethylenediamine realize the high-phase separation of PSS and PEDOT through hydrogen bond association on one hand, optimize the conformation of a PEDOT molecular chain, enable the PEDOT to form an orderly arranged conductor continuous phase, and bond with TPU through coordination, electrostatic interaction, hydrophobic interaction and even covalent reaction on the other hand; the valence bond crosslinking strategy refers to a process of obtaining a stable conductive network structure through dynamic valence bond crosslinking among different substances; the multidimensional conductive network structure refers to: on the one hand, the two-dimensional conductive network structure between PEDOT and silver nano particles, and on the other hand, the three-dimensional conductive network structure between MXene or derivatives thereof and carbon nano tubes or derivatives thereof and silver nano particles. In addition, the dispersion and reagglomeration problems of the conductive nano filler are solved by adopting a wet spinning method, compared with the prior art, the method for preparing the fiber is simple, has the advantages of simple equipment, simple spinning process, environment friendliness and remarkable effect improvement, does not need expensive and complex equipment, is easy to realize mass production, has good flexibility, tensile property and large-scale integration property, and can be widely applied to wearable devices. The conductive composite fiber prepared by adopting the valence bond crosslinking strategy solves the problems of poor dispersibility and easy aggregation of PEDOT, and simultaneously, the crosslinking of the carbon nano tube and the derivative thereof, the MXene and the derivative thereof and the metal nano silver particles further improves the continuity and controllability of the three-dimensional conductive network structure, so that the conductive filler can be uniformly dispersed, the raw materials are saved, the conductivity and the structural stability of the composite material are improved, and a new thought is provided for the development of new conductive fibers.

For a better understanding of the present application, a specific example is used below to further describe the present application. It should be noted that the embodiments described in this specific embodiment are only some embodiments of the present application, and do not limit the scope of protection of the present application.

A preparation method of a flexible PEDOT (polyethylene terephthalate) PSS conductive composite fiber comprises the following steps:

In step S1 of this example, the TPU content is 5g/L; the mass volume concentration of DMF is 150mg/mL; the constant temperature of the constant temperature magnetic stirrer is 45 ℃, the stirring speed is 300rpm, and the stirring time is 5h.

And S2, adding the PEDOT-PSS into the mixed solution containing the gallic acid, the hexamethylenediamine and the Tris buffer solution, and stirring by using a constant-temperature magnetic stirrer to obtain the PEDOT-PSS mixed solution.

In the step S2 of the embodiment, the concentration of PEDOT to PSS is 20mol/L; the concentration of the gallic acid is 25mol/L; the concentration of hexamethylenediamine is 25mol/L; the concentration of Tris buffer was 1mol/L. Specifically, the pH of the solution obtained by adding PEDOT: PSS to a mixed solution containing gallic acid or a derivative thereof, hexamethylenediamine and Tris buffer is 8.5; the constant temperature of the constant temperature magnetic stirrer is 45 ℃, the stirring speed is 300rpm, and the stirring time is 30min.

In step S3 of this embodiment, CNTs-DMPA, MXene (Ti ₃ C ₂ T _x ) And the concentration of silver powder was 6.5mol/L, 3.2mol/L and 5.5mol/L, respectively. In addition, the constant temperature of the constant temperature magnetic stirrer is 45 ℃; the initial stirring speed of the constant temperature magnetic stirrer is set to be 250rpm, and stirring is continued for 1.5h; then the stirring speed is adjusted to 600rpm, and stirring is continued for 30min; finally stirThe speed was adjusted to 950rpm and stirring was continued for 6h.

In step S4 of this example, the constant temperature of the constant temperature magnetic stirrer was 45℃and the stirring speed was 450rpm, and the stirring time was 6 hours.

And S5, injecting the PEDOT-PSS mixed spinning solution into an injector, carrying out wet spinning at normal temperature, extruding the PEDOT-PSS mixed spinning solution into DMF aqueous coagulating bath by using an injection pump, carrying out three times of mechanical drawing on primary fibers coagulated and molded by the coagulating bath, carrying out heat setting treatment, and finally winding the fibers subjected to the heat setting treatment on a heat roller rotating at a constant speed for collection and drying to obtain the flexible PEDOT-PSS conductive composite fiber shown in the figure 2.

In step S5 of this example, the volumetric capacity of the syringe was 30mL and the inside diameter of the needle was 0.28mm; the spinning speed of wet spinning is 3.6mL/h; the length of the coagulation bath is 90cm; the heat setting treatment temperature was 60 ℃. In addition, the fiber after the heat setting treatment was wound on a heat roller rotating at a constant speed, and the drying temperature during the collection and drying was 30℃and the drying time was 8 hours.

The 2, 2-dimethylolpropionic acid (DMPA) used in this example was purchased from Nanjing Runbang chemical Co., ltd, and N, N-Dimethylformamide (DMF) was purchased from Tianjin metallocene chemical reagent plant, thionyl chloride (SOCl) ₂ ) Available from Tianjin Chemicals Inc., nanometer silver powder and Ti ₃ AlC ₂ MAX is purchased from Nanjing Xianfeng nano materials science and technology Co., ltd, triethylamine (TEA) is purchased from national drug group chemical reagent Co., ltd, lithium fluoride LiF analytically pure (AR) is purchased from Shanghai Michelin Biochemical technology Co., ltd, HCl analytically pure (AR) is purchased from Zhuhai Huacheng Chemie Co., ltd, and other solution which is not specifically described is water as solvent.

Further, the preparation method of the MXene nano-lamellar powder in the example comprises the following steps:

from MAX phase (Ti by using LiF/HCl aqueous solution ₃ AlC ₂ ) Preparation of MXene (Ti) by selectively etching away Al layer ₃ C ₂ T _x ). First, 2.5g of LiF was dispersed in 50mL of hydrochloric acid solution (12 mol/L) with stirring; then 2.5g of MAX (Ti) ₃ AlC ₂ ) The method comprises the steps of carrying out a first treatment on the surface of the Subsequently reacting the solution at 40 ℃ for 48 hours under magnetic stirring to completely etch away the Al layer; after 48 hours, diluting the obtained product with deionized water, centrifuging, and repeating for several times until the pH of the supernatant is greater than 6; and finally, freeze-drying the precipitate obtained by centrifugation for 12 hours to obtain the MXene nano-sheet layer. In order to obtain a few-layer or single-layer MXene nano-sheet, the obtained MXene nano-sheet layer is subjected to further stripping treatment; mixing the MXene nano-sheet layer with an intercalation agent, performing ultrasonic treatment for a period of time under the ice bath condition by using a cell pulverizer, and centrifuging to collect a lower-layer precipitate; mixing the precipitate with deionized water, and then uniformly dispersing MXene in water by ultrasonic treatment; collecting supernatant after centrifugation, wherein the supernatant is a few-layer MXene dispersion liquid; and finally, freeze-drying the dispersion liquid to obtain the few-layer MXene nano-sheet powder.

Further, the preparation method of CNTs-DMPA powder in the example comprises:

3.0g of carboxylated CNTs are placed in a 500mL four-necked flask, 30mL of DMF is added, ultrasonic dispersion is carried out for 30min, stirring is started, and then 100mL of SOCl is slowly added ₂ The reaction was heated to 70℃and stirred for 16h. After cooling, suction filtration and washing with DMF 3 times, the surface of which was freed from unreacted SOCl ₂ . The filter cake was transferred to a 500mL Erlenmeyer flask, 80g of DMPA (DMF as solvent) and 20mL of TEA were added separately, heated to 50deg.C and magnetically stirred for 24h. After cooling, suction filtration is carried out, the filter cake is washed by deionized water for 5 times, and then is dried to constant weight in an oven at 60 ℃ to obtain chemically modified CNTs, which are marked as CNTs-DMPA.

Next, the flexible PEDOT: PSS conductive composite fiber obtained above was subjected to performance test:

1. mechanical property test

The fibers were tested for stretch-break at room temperature using a universal test machine for UTM2203 servo control from Shenzhen Sansi Verand technologies, inc., at a stretch rate of 10mm/min, at least 5 samples per content and the average value calculated.

1.1, the tensile strength of the test specimen is calculated using the following equation:

wherein σ is tensile strength (Pa); p is the maximum load (N); s is the cross-sectional area (m) ² )。

1.2, the elongation at break of the test sample is calculated by adopting the following formula II:

wherein: epsilon is the elongation at break; l (L) ₀ Is the initial length (mm) of the sample; l is the length (mm) of the sample after stretching.

The young's tensile modulus of the test specimen was calculated using the following formula three:

wherein E is the Young's tensile modulus (MPa) of the test specimen; epsilon is a certain strain quantity of the elastic region of the sample; sigma is the tensile strength (MPa) corresponding to the elastic region of the sample when it becomes epsilon.

2. Conductivity test

Cut 5cm long fiber and apply silver colloid on both ends and connect copper tape, each content is tested at least 5 samples, and calculate its average value, the bulk conductivity of the sample uses the following formula four to calculate:

wherein σ is the bulk conductivity of the sample (S/cm ^-1 ) The method comprises the steps of carrying out a first treatment on the surface of the R is the volume resistance (omega/cm) of the sample; l is the length (cm) of a spline between the two electrodes;s is the cross-sectional area (cm) of the sample ² )。

3. Friction resistance test

The test was performed with reference to national standard GB/T21196.

4. Water resistance test

The tests were carried out with reference to the literature (Dca B, xue B, jpa B, et al, in situ hydrothermal growth of Cu NPs on knitted fabrics through polydopamine templates for heating and sensing [ J ]. Chemical Engineering Journal, 382.).

The test results were as follows:

fig. 3 shows gallic acid or derivatives thereof doped with hexamethylenediamine versus PEDOT: the mechanism of action of the PSS chemical structure is schematically shown in fig. 3:

on the one hand, the association of the gallic acid 1 with the amino groups and the phenolic hydroxyl groups in the hexamethylenediamine 2 through the hydrogen bonds 5 and 6 realizes the high-phase separation of the PSS 3 and the PEDOT 4, optimizes the conformation of the PEDOT molecular chain, and enables the PEDOT to form an orderly arranged conductor continuous phase.

On the other hand, FIG. 4 shows a schematic diagram of the synthetic mechanism and chemical structure between PEDOT conductive composite and TPU functionally modified with gallic acid or its derivatives, PEDOT 1 is inter-bonded with TPU 2 through hydrogen bond interaction 3, while PEDOT, CNTs-DMPA4, MXene (Ti ₃ C ₂ T _x ) And (5) a process of obtaining a stable conductive network structure by dynamic valence crosslinking 7 and 8 between the metal nano silver 6 particles. The multidimensional conductive network structure refers to: on the one hand, the two-dimensional conductive network structure between the PEDOT and the silver nano particles; on the other hand, MXene (Ti ₃ C ₂ T _x ) And a three-dimensional conductive network structure between CNTs-DMPA and silver nanoparticles.

The flexible PEDOT-PSS conductive composite fiber prepared by the preparation method has tensile strength of 780.62MPa, strain of 1204.28% and conductivity of 2405S/cm. As shown in the following tables 1 and 2, the PEDOT is the friction resistance and water washing resistance test result of the PSS conductive composite fiber, and as can be seen from the tables 1 and 2, the conductivity of the PEDOT is within 2369-2405S/cm after 650 times of friction; after 240 water washes, the conductivity is within 2365-2405S/cm.

TABLE 1 results of abrasion resistance test

Number of rubs/time of rubs	conductivity/S/cm
		0	2405
50	2403
		150	2398
250	2392
		350	2387
450	2379
		550	2373
650	2369

TABLE 2 washing resistance test results

The foregoing is merely a preferred embodiment of the present application, and it should be noted that: it will be apparent to those skilled in the art that numerous modifications and variations can be made thereto without departing from the principles of the present application, and such modifications and variations are to be regarded as being within the scope of the application.

Claims

1. The preparation method of the flexible PEDOT-PSS conductive composite fiber is characterized by comprising the following steps of:

2. The method for preparing the flexible PEDOT: PSS conductive composite fiber according to claim 1, wherein in the step S1:

the content of the TPU is 2-10g/L;

the mass volume concentration of the DMF is 20-200mg/mL;

3. The method for preparing the flexible PEDOT: PSS conductive composite fiber according to claim 1, wherein in the step S2:

the concentration of PEDOT and PSS is 10-60mol/L;

the concentration of the gallic acid or the derivative thereof is 15-45mol/L;

the concentration of the hexamethylenediamine is 15-65mol/L;

the concentration of the Tris buffer solution is 0.5-4.5mol/L.

4. The method for preparing the flexible PEDOT: PSS conductive composite fiber according to claim 1, wherein in the step S2:

5. The method for preparing the flexible PEDOT: PSS conductive composite fiber according to claim 1, wherein in the step S2:

6. The method for preparing the flexible PEDOT: PSS conductive composite fiber according to claim 1, wherein in the step S3:

7. The method for preparing the flexible PEDOT: PSS conductive composite fiber according to claim 1, wherein in the step S3:

8. The method for preparing the flexible PEDOT: PSS conductive composite fiber according to claim 1, wherein in the step S4:

9. The method for preparing the flexible PEDOT: PSS conductive composite fiber according to claim 1, wherein in the step S5:

the spinning speed of the wet spinning is 0.5-6.5mL/h;

the length of the coagulating bath is 90cm;

the temperature of the heat setting treatment is 60 ℃;

10. A flexible PEDOT: PSS conductive composite fiber prepared by the method of preparing a flexible PEDOT: PSS conductive composite fiber according to any one of claims 1 to 9.