Emulsion polymerization chloride ion doped PEDOT nano-particles as well as preparation method and application thereof

Abstract

The invention relates to emulsion polymerization chloride ion doped PEDOT nanoparticles as well as a preparation method and application thereof. The preparation method comprises the following steps: adding dodecyl trimethyl ammonium chloride into water, and uniformly stirring to obtain a micelle solution; adding EDOT into the micelle solution, and stirring to form an emulsion; under a stirring condition, dropwise adding an oxidant solution into the emulsion; after dropwise adding the oxidant solution, carrying out emulsion polymerization reaction to obtain a mixture; and S5, carrying out solid-liquid separation, washing and drying on the mixture to obtain the chloride ion doped PEDOT nano-particles. According to the invention, the cationic surfactant dodecyl trimethyl ammonium chloride is used as an emulsifier and a dopant, the formed micelle wraps the EDOT, so that the reaction can be carried out in a water phase, the high-performance pure chloride ion doped PEDOT can be prepared through emulsion polymerization reaction, the method process is simple, the requirement on equipment is low, and the synthesized PEDOT has good conductivity.

Description

Technical Field

[0001] The present invention relates to the field of conductive materials, and in particular to an emulsion-polymerized chloride ion-doped PEDOT nanoparticle, a preparation method thereof, and an application thereof. Background Art

[0002] Conductive polymers are polymer compounds with certain electrical conductivity properties. They are also a class of polymer materials with a conjugated backbone structure, typically achieved through chemical or electrochemical doping. These materials possess many unique physical and chemical properties, giving them broad application prospects in electronics, energy conversion, biomedicine, and storage. Among them, PEDOT (poly(ethylenedioxythiophene)) is currently one of the best conductive polymers. In recent years, research on the applications of PEDOT has been extensively conducted.

[0003] PEDOT is a conductive polymer with excellent electrical conductivity, but its monomers have low solubility in water, a high oxidative polymerization potential, and are susceptible to reaction with protophilic substances in solution. Consequently, traditional oxidative polymerization methods are conducted in anhydrous organic solvents, resulting in high production costs, low efficiency, and significant environmental pollution. In recent years, efforts to adapt these methods for large-scale industrial applications have increasingly focused on aqueous system reactions. To improve the water solubility of monomers or polymers, ionic or nonionic surfactants are added during the polymerization process to increase the monomer's solubility in water and enable water-soluble oxidants to oxidatively polymerize PEDOT in the aqueous phase. Compared to traditional oxidative polymerization methods, this method offers lower costs, simpler processing, and lower environmental pollution, making it more suitable for large-scale production. However, it often introduces various impurities.

[0004] In addition to the preparation process, doping is also a major factor influencing PEDOT's performance. Anion doping is typically achieved through oxidizing agents or acid treatment. Common dopants include organic acids, inorganic acids, and ionic liquids. Effective anion doping can improve PEDOT's conductivity and enhance the stability of PEDOT films. Currently, the main PEDOT product on the market is PEDOT:PSS. The addition of PSS (polystyrene sulfonic acid) improves PEDOT's solubility in water and enhances its stability and mechanical properties. However, excessive addition of PSS can reduce PEDOT's original conductivity and affect the performance of devices fabricated with it. Summary of the Invention

[0005] The purpose of the present invention is to overcome the above technical deficiencies and provide an emulsion polymerization chloride ion doped PEDOT nanoparticles and their preparation method and application, so as to solve the technical problems of multiple impurities and low conductivity of PEDOT prepared in the prior art.

[0006] In order to achieve the above technical objectives, the technical solution provided by the present invention is: In a first aspect, the present invention provides a method for preparing chloride ion-doped PEDOT nanoparticles by emulsion polymerization, comprising the following steps: S1, adding dodecyltrimethylammonium chloride to water and stirring uniformly to obtain a micellar solution; S2, adding EDOT to the micellar solution and stirring to form an emulsion; S3, dropwise adding an oxidant solution to the emulsion under stirring; S4, after the dropwise addition of the oxidant solution is completed, performing an emulsion polymerization reaction to obtain a mixture; S5, subjecting the mixture to solid-liquid separation, washing, and drying to obtain chloride ion-doped PEDOT nanoparticles.

[0007] In a second aspect, the present invention provides PEDOT nanoparticles prepared by the above preparation method.

[0008] In a third aspect, the present invention provides a use of the above-mentioned PEDOT nanoparticles as a conductive material.

[0009] Compared with the prior art, the present invention has the following beneficial effects: The present invention uses a cationic surfactant, dodecyltrimethylammonium chloride, as an emulsifier and dopant, continuously stirs to fully dissolve the dodecyltrimethylammonium chloride in water to form a micellar solution, then adds EDOT, allows the dodecyltrimethylammonium chloride micelles to wrap the EDOT, fully emulsifies and disperses the EDOT monomer, and enables the reaction to proceed in the aqueous phase. High-performance, pure chloride ion-doped PEDOT can be prepared through emulsion polymerization. The method has a simple process, low equipment requirements, and is environmentally friendly. The synthesized PEDOT is nano-aggregate particles without other miscellaneous ion doping, has good electrical conductivity, and has improved dispersibility in water compared to other PEDOTs, thereby increasing its application potential. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] Figure 1 1 is a graph showing the water dispersibility of PEDOT obtained in Example 1 of the present invention and Comparative Examples 5-6. DETAILED DESCRIPTION

[0011] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0012] In response to the many shortcomings of traditional PEDOT preparation methods and traditional water-based precipitation polymerization methods for preparing PEDOT powder, such as the large number of impurities, high energy consumption, complex production process, and low electrical conductivity, the present invention provides emulsion-polymerized chloride-ion-doped PEDOT nanoparticles and their preparation method and application. A simpler and more environmentally friendly emulsion polymerization process is used to prepare pure chloride-ion-doped PEDOT products with high performance and processability.

[0013] In a first aspect, the present invention provides a method for preparing chloride ion-doped PEDOT nanoparticles by emulsion polymerization, comprising the following steps: S1, adding dodecyltrimethylammonium chloride into water and stirring uniformly to obtain a micellar solution; S2, adding EDOT to the micellar solution and stirring to form an emulsion; S3, adding the oxidant solution dropwise to the emulsion under stirring; S4, after the oxidant solution is added dropwise, an emulsion polymerization reaction is performed to obtain a mixture; S5, the mixture is subjected to solid-liquid separation, washing and drying to obtain chloride ion-doped PEDOT nanoparticles.

[0014] The present invention uses dodecyltrimethylammonium chloride as an emulsifier and dopant, continuously stirs to fully dissolve the dodecyltrimethylammonium chloride in water, and forms a micellar solution (a clear and transparent aqueous solution with white foam), then adds EDOT, and continuously stirs to allow the dodecyltrimethylammonium chloride micelles to wrap the EDOT, fully emulsifying and dispersing the EDOT monomer, thereby obtaining an emulsion with a white foamy solution on the surface and a slightly yellowish interior, and then adds an oxidant solution. Through emulsion polymerization, high-performance, pure chloride ion-doped nano-aggregate particle PEDOT powder can be prepared.

[0015] At the same time, the order of the steps in the present invention must first form an aqueous emulsion of EDOT, and then add an oxidant solution to the emulsion to initiate the oxidation reaction; this is because the latex particles formed by micelles formed by dodecyltrimethylammonium chloride encapsulating EDOT are the primary site of reaction between the oily monomer EDOT and the aqueous oxidant. A stable latex particle state is a prerequisite for maintaining a stable reaction and also affects the yield and performance of the product. If the above steps are not followed, whether a mixed solution of the oxidant and dodecyltrimethylammonium chloride is first prepared and then the monomer is added, or the oxidant is added before the dodecyltrimethylammonium chloride solution and the monomer have fully formed latex particles, the reaction will be unstable and incomplete. The reaction in this case is not a homogeneous reaction, which will seriously affect the reaction process and the yield and performance of the product.

[0016] Furthermore, to achieve the single chloride ion doping requirement of the present invention, the cationic surfactant long-chain alkyl trimethyl ammonium chloride was selected. However, when the alkyl chain is too short, such as (C6-C8), the long-chain alkyl trimethyl ammonium chloride has poor emulsification and dispersibility, failing to effectively emulsify the EDOT monomer. Compared to dodecyl trimethyl ammonium chloride, tetradecyl trimethyl ammonium chloride, and hexadecyl trimethyl ammonium chloride, dodecyl trimethyl ammonium chloride has better water solubility and a lower critical micelle concentration (CMC), allowing it to effectively emulsify and disperse the EDOT monomer at lower concentrations. Furthermore, dodecyl trimethyl ammonium chloride is less irritating to humans, more environmentally friendly, and more cost-effective. Therefore, dodecyl trimethyl ammonium chloride was selected as the emulsifier and dopant used in the present invention.

[0017] Furthermore, the micellar solution is formed by mixing dodecyltrimethylammonium chloride and water in a ratio of (2-6.5) g:400 mL.

[0018] Furthermore, the molar ratio of EDOT to dodecyltrimethylammonium chloride is 1:(0.25-0.7).

[0019] Furthermore, the molar ratio of EDOT to dodecyltrimethylammonium chloride is 1:(0.5-0.65).

[0020] In the present invention, the proper ratio of EDOT to dodecyltrimethylammonium chloride is key to synthesizing high-performance products. Too little dodecyltrimethylammonium chloride results in insufficient micelles to fully emulsify the monomers, causing the unemulsified monomers to react in a suspension polymerization manner, ultimately resulting in an inhomogeneous product with poor performance. Excessive dodecyltrimethylammonium chloride, the surfactant, makes subsequent washing more difficult and has environmental impacts.

[0021] Furthermore, the stirring rate is 550-800 rpm. Step S2 and subsequent steps of the present invention are all performed under high-speed stirring. High-speed stirring ensures micelle stability and phase homogeneity. Excessively low stirring speeds hinder the micelle encapsulation of monomers to form latex particles, resulting in a non-uniform reaction. Furthermore, sufficient dispersion of the solid product is ensured. Furthermore, if a device with a non-constant stirring rate, such as a magnetic stirrer, is used, the magnets will be affected by the viscosity of the product after formation. Therefore, the magnetic stirring speed should be appropriately increased during the polymerization reaction.

[0022] Furthermore, the oxidant solution is a 1.4-3.0 mol / L ferric chloride solution.

[0023] Furthermore, the molar ratio of EDOT monomer to ferric chloride is 1:(4-8).

[0024] In the present invention, increasing the concentration of the oxidant can increase the degree of reaction and improve product performance. The ferric chloride hexahydrate solution is added slowly dropwise, and gradually increasing the oxidant concentration is conducive to the stable progress of the reaction, thereby ensuring that the instantaneous concentration of the oxidant in the reaction is not too high, resulting in sudden polymerization of the reaction and affecting the performance of the product.

[0025] Furthermore, based on the total amount of water in the micellar solution and the oxidant solution, the concentration of dodecyltrimethylammonium chloride relative to the total water is 35 to 46 mmol / L. The total amount of water used in the experiment is the sum of the amount of water used to dissolve the oxidant, the water content of the oxidant itself, and the amount of water used to dissolve the dodecyltrimethylammonium chloride, so as to control the concentration of the dodecyltrimethylammonium chloride to meet the requirements.

[0026] Furthermore, the emulsion polymerization reaction is carried out at 15-40° C. for 72-168 hours. In the present invention, if the reaction temperature is too low, the reaction will be slow or stopped, and if the temperature is too high, it will cause violent polymerization.

[0027] Furthermore, no auxiliary agents other than the above-mentioned raw materials are added during the reaction process of the present invention; the solid product of the present invention can be washed with water, anhydrous ethanol, etc.; a variety of cleaning liquids can be used alternately for cleaning during the cleaning process; it can be understood that, within a certain range, the more times the cleaning is done, the higher the degree of cleaning.

[0028] Furthermore, after the reaction is complete, the reaction liquid is filtered to separate the solid and liquid, leaving a solid product. Initially, the product can be washed with water or ethanol to remove a large amount of oxidant, dodecyltrimethylammonium chloride, and unreacted monomers or oligomers. It is then washed with a 1 mol / L hydrochloric acid solution to completely remove the iron ions in the product. Subsequently, the residual hydrochloric acid and dodecyltrimethylammonium chloride can be washed with a large amount of distilled water. During this period, ultrasonic heating can be used for cleaning, with the temperature set at 80°C and ultrasonication for 30 minutes each time to fully disperse the product and release impurities encapsulated within the product. After ultrasonic cleaning, the PEDOT solid product is separated by filtration. After washing, the solid product is placed in a vacuum drying oven and vacuum-dried at 80°C for 48 hours to obtain PEDOT nanoparticles.

[0029] In a second aspect, the present invention provides PEDOT nanoparticles prepared by the above preparation method.

[0030] In a third aspect, the present invention provides a use of the above-mentioned PEDOT nanoparticles as a conductive material.

[0031] The main advantages of the present invention are: (1) The preparation process was designed more scientifically, giving full play to the role of dodecyltrimethylammonium chloride and the oxidant in this preparation method.

[0032] (2) The anion of the selected surfactant, dodecyltrimethylammonium chloride, is consistent with that of the oxidant. The synthesized PEDOT is free of other impurities and is in a pure chloride ion-doped state. This product has better chemical stability and more flexible processing properties than commercial PEDOT:PSS.

[0033] (3) The electrical conductivity of the chloride ion-doped PEDOT nanoparticles prepared by the method of the present invention is higher than that of the chloride ion-doped PEDOT products prepared by the traditional method.

[0034] In summary, the present invention has a simple process, low equipment requirements, is environmentally friendly, and is suitable for large-scale production. The product's single ion doping characteristics, nano-collective particle structure, and good electrical conductivity give it greater application potential.

[0035] The present invention is further described in detail below through specific examples.

[0036] Example 1 A method for preparing chloride ion-doped PEDOT nanoparticles by emulsion polymerization comprises the following steps: S1. Micellar solution: 400 ml of distilled water and 6.10 g of dodecyltrimethylammonium chloride were added to a conical flask. A magnetic stirrer was added and the conical flask was placed in a magnetic stirrer in a 40° C. water bath and stirred for 30 min to obtain a micellar solution.

[0037] S2. Emulsification and dispersion of EDOT: Add 5g of EDOT dropwise to the micelle solution and stir at 600 rpm to fully encapsulate the EDOT in the dodecyltrimethylammonium chloride micelles, forming a white emulsion with a slightly yellowish tint. The molar ratio of EDOT to dodecyltrimethylammonium chloride is 1:0.65.

[0038] S3. Add the oxidant, ferric chloride hexahydrate solution: Weigh 39.24 g of ferric chloride hexahydrate (4 times the molar ratio of EDOT, containing 15.21 mL of water) and dissolve it in 84.79 mL of distilled water to obtain an oxidant solution. Slowly add the oxidant solution dropwise to the EDOT dispersion using a constant pressure titration funnel for at least 2 hours.

[0039] S4. EDOT Polymerization: Maintain the reaction temperature at 40°C. A small amount of product will form after the oxidant solution is added. Because the magnetic stirrer operates at a non-constant stirring rate, the magnet will be affected by the viscosity of the product. Therefore, the magnetic stirring speed should be increased appropriately. As the reaction progresses and the product continues to increase, the magnetic stirring speed should be increased to maintain high stirring (mechanical stirring at 600 rpm is also acceptable) to ensure a uniform reaction. The reaction should last for 3 days.

[0040] S5. Collection, Washing, and Drying of PEDOT: After the reaction is complete, the reaction mixture is filtered using a G6 fritted funnel to obtain a blue-black wet solid PEDOT product. This wet product contains a large amount of unremoved surfactant, oxidant, monomer, or oligomer impurities. Disperse the wet product with ethanol to dissolve out monomer and oligomer impurities. Repeat this process three times until the washed ethanol is colorless. Wash with 1 mol / L hydrochloric acid solution until no colored iron ion solution remains. Disperse with a large amount of distilled water and filter the wet product. The wet PEDOT product can be transferred to a 500 mL beaker and treated with 1 mol / L hydrochloric acid (e.g., 100 mL) or a large amount of distilled water (e.g., 400 mL). Heat and sonicate at 80°C for 30 minutes to fully disperse the wet product and release any entrained surfactant and iron salt impurities. After sonication, filter the solid product using a fritted funnel. Repeat this washing process. After washing with hydrochloric acid, rinse the product with distilled water until neutral. Finally, the wet product was soaked in ethanol for 15 minutes and then filtered to remove any residual moisture for easy drying. The treated wet product was then placed in a vacuum drying oven and dried at 80°C for 48 hours. The resulting PEDOT solid product was dark bluish-black. The resulting PEDOT solid product was then crushed into powder using an agate mill, yielding the resulting PEDOT powder sample.

[0041] Example 2 Compared with Example 1, the only difference is that the amount of dodecyltrimethylammonium chloride is adjusted to 4.69 g (ie, the molar ratio of EDOT to dodecyltrimethylammonium chloride is 1:0.5). Other steps and conditions are the same as in Example 1.

[0042] Example 3 Compared with Example 1, the only difference is that the amount of dodecyltrimethylammonium chloride is adjusted to 3.52 g (ie, the molar ratio of EDOT to dodecyltrimethylammonium chloride is 1:0.375). Other steps and conditions are the same as in Example 1.

[0043] Example 4 Compared with Example 1, the only difference is that the amount of dodecyltrimethylammonium chloride is adjusted to 2.35 g (ie, the molar ratio of EDOT to dodecyltrimethylammonium chloride is 1:0.25). Other steps and conditions are the same as in Example 1.

[0044] Example 5 Compared with Example 1, the only difference is that the amount of oxidant is different. Specifically, 58.86 g of the oxidant ferric chloride hexahydrate (6 times the molar number of EDOT, containing 22.81 mL of water) is weighed and added to 77.19 mL of distilled water to dissolve to obtain an oxidant solution; the other steps and conditions are the same as in Example 1.

[0045] Example 6 Compared with Example 1, the only difference is that the amount of oxidant is different. Specifically, 78.47 g of the oxidant ferric chloride hexahydrate (8 times the molar number of EDOT, containing 30.41 mL of water) is weighed and added to 69.59 mL of distilled water to dissolve to obtain an oxidant solution; the other steps and conditions are the same as in Example 1.

[0046] Example 7 Compared with Example 6, the only difference is that the reaction time in step S4 is 5 days; the other steps and conditions are the same as those in Example 6.

[0047] Example 8 Compared with Example 6, the only difference is that the reaction time in step S4 is 7 days; the other steps and conditions are the same as those in Example 6.

[0048] Comparative Example 1 Compared with Example 1, the only difference is that EDOT and the oxidant solution are simultaneously added dropwise to the micelle solution to carry out the polymerization reaction in step S4; the other steps and conditions are the same as those in Example 1.

[0049] Comparative Example 2 Compared with Example 2, the only difference is that EDOT and the oxidant solution are simultaneously added dropwise to the micelle solution to carry out the polymerization reaction in step S4; the other steps and conditions are the same as those in Example 2.

[0050] Comparative Example 3 Compared with Example 3, the only difference is that EDOT and the oxidant solution are simultaneously added dropwise to the micelle solution to carry out the polymerization reaction in step S4; the other steps and conditions are the same as those in Example 3.

[0051] Comparative Example 4 Compared with Example 4, the only difference is that EDOT and the oxidant solution are simultaneously added dropwise to the micelle solution to carry out the polymerization reaction in step S4; the other steps and conditions are the same as those in Example 4.

[0052] Comparative Example 5 Compared with Example 1, the only difference is that sodium lauryl sulfate is used instead of dodecyltrimethylammonium chloride, and its dosage is adjusted so that the molar ratio of EDOT to sodium lauryl sulfate is 1:0.25 (at this time, the purpose of complete emulsification of the monomers can be achieved); the other steps and conditions are the same as in Example 1.

[0053] Comparative Example 6 Compared with Example 1, the only difference is that dodecyltrimethylammonium chloride in step S1 is removed; the other steps and conditions are the same as those in Example 1 (ie, PEDOT is prepared by suspension polymerization).

[0054] PEDOT powder performance test: 1. PEDOT conductivity test method: Pour 0.1g of PEDOT powder into a tableting mold, apply a gradient pressure to 40mPa, and maintain the pressure for 30 minutes. Then, remove the PEDOT sheet, measure its thickness, and test its conductivity using a four-probe resistivity meter (Mitsubishi MCP-TP610, MCP-TP06P, and RMH311). This test determines the conductivity of the PEDOT powder.

[0055] 2. PEDOT conversion rate test method: The conversion rate calculation formula is as follows:

[0056] Where: To collect the quality of the product; is the mass of EDOT monomer added. After drying, collect the PEDOT solid and calculate the PEDOT conversion rate according to this formula.

[0057] The conductivity and conversion rate of PEDOT obtained in the above examples and comparative examples were statistically analyzed, and the results are shown in Table 1 below.

[0058] Table 1 Conductivity and conversion rate of PEDOT obtained in various examples and comparative examples

[0059] As shown in Table 1, in Examples 1-4, the amount of dodecyltrimethylammonium chloride was gradually reduced, with the molar ratio of EDOT to dodecyltrimethylammonium chloride being 1:0.65, 1:0.5, 1:0.375, and 1:0.25, respectively. The resulting reaction product conductivity and yield decreased. This was primarily due to the fact that when the molar ratio of EDOT to dodecyltrimethylammonium chloride was 1:0.25, a large amount of monomer remained unemulsified, remaining dispersed in the solution as small droplets. If the stirring speed was reduced, the droplets would precipitate. As the amount of dodecyltrimethylammonium chloride increased, a large amount of the unemulsified monomer was emulsified. When the ratio reached 1:0.65, the monomer was completely emulsified, with no oily droplets present, forming a white, slightly yellowish emulsion.

[0060] Therefore, it can be seen that the surfactant emulsifies the monomers and provides a reaction site. Increasing the amount of surfactant can effectively increase the reaction rate. In the present invention, the molar ratio of EDOT to dodecyltrimethylammonium chloride is selected to be 1:(0.25-0.7), and more preferably 1:(0.5-0.65). However, too little surfactant will prevent complete emulsification of the monomers, while too much surfactant will hinder washing and impurity removal. Therefore, the optimal amount of surfactant is selected to fully emulsify the reacting monomers, that is, 1:0.65 is most preferred. This invention scientifically optimizes the surfactant ratio during the experimental process based on the critical micelle concentration of the surfactant, greatly improving the product conversion rate and conductivity, and is a more scientific and simple preparation technology.

[0061] From the comparison between Example 1 and Examples 5-6, it can be seen that under the condition of appropriate surfactant concentration, increasing the oxidant concentration can effectively increase the reaction process of the product.

[0062] From the comparison of Examples 6-8, it can be seen that under the reaction conditions of 40°C and 8 times the oxidant concentration, a higher conductivity can be reached after 72 hours of reaction. Subsequent extension of the reaction time will cause the conductivity to decrease after reaching the peak value. The reason is that the long reaction time causes the nanoparticle product to agglomerate.

[0063] In Comparative Examples 1-4, EDOT and an oxidant were directly added to the micellar solution. It was found that with the increase in the amount of dodecyltrimethylammonium chloride, the conductivity of the reaction product showed an upward trend, but was significantly lower than that of Examples 1-4, and the product conversion rate was below 10%.

[0064] 3. PEDOT dispersion test: Weigh 0.1g of the PEDOT powder obtained in Example 1 and Comparative Examples 5-6 respectively, grind them into a uniform powder using a mortar, and add 10ml of deionized water. After ultrasonic dispersion for 1 hour, take it out and let it stand for 24 hours before observing the phenomenon. The results are as follows Figure 1 shown.

[0065] Among them, (a) is the PEDOT powder obtained in Comparative Example 5, (b) is the PEDOT powder obtained in Comparative Example 6, and (c) is the PEDOT powder obtained in Example 1.

[0066] Depend on Figure 1 The results show that the comparative example 5 uses an anionic surfactant, and the obtained powder is dodecyl sulfate-doped PEDOT. Figure 1 As shown in (a), the long-chain alkyl-doped PEDOT powder is hydrophobic and has poor dispersion ability in water; Figure 1As shown in (b), the dispersibility of the chloride ion-doped PEDOT powder prepared by suspension polymerization in Comparative Example 6 is improved compared with the PEDOT powder in Comparative Example 5. However, the powder in Comparative Example 6 is severely agglomerated, and the large particles seriously affect its dispersibility.

[0067] like Figure 1 As shown in (c), the emulsion-polymerized chloride-doped PEDOT powder of the present invention exhibits only a small amount of precipitation after 24 hours of ultrasonic dispersion, maintaining an overall dispersed state and exhibiting optimal dispersibility. This is due to the fact that the micelles of dodecyltrimethylammonium chloride in the emulsion polymerization reduce agglomeration during the PEDOT polymerization reaction. The resulting PEDOT powder is nanoparticle-like, free of large particle agglomerations, and exhibits improved dispersibility in water. Therefore, the PEDOT obtained in this invention exhibits excellent dispersibility in water and is suitable for use in non-organic solvent environments.

[0068] In summary, the present invention uses the cationic surfactant dodecyltrimethylammonium chloride to emulsify the monomer in water, allowing the reaction to proceed in the aqueous phase. Furthermore, the cationic surfactant, dopant trimethylammonium chloride, has the same anion as the oxidant ferric chloride, resulting in the synthesis of a PEDOT product doped solely with chloride ions. This method is simple, requires minimal equipment, and is environmentally friendly. The resulting PEDOT is a nano-aggregate particle, free of other ion doping, exhibiting excellent conductivity and improved dispersibility in water compared to other PEDOTs, increasing its potential for application.

[0069] The specific embodiments of the present invention described above do not limit the scope of protection of the present invention. Any other corresponding changes and modifications made based on the technical concept of the present invention should be included in the scope of protection of the claims of the present invention.

Claims

1. A method for preparing chloride ion-doped PEDOT nanoparticles by emulsion polymerization, characterized in that: The following steps are involved: S1, adding dodecyltrimethylammonium chloride into water and stirring uniformly to obtain a micellar solution; S2, adding EDOT to the micellar solution and stirring to form an emulsion; S3, adding an oxidant solution dropwise to the emulsion under stirring; S4, after the dropwise addition of the oxidant solution is completed, performing an emulsion polymerization reaction to obtain a mixture; S5, the mixture is subjected to solid-liquid separation, washing and drying to obtain chloride ion-doped PEDOT nanoparticles.

2. The method for preparing emulsion-polymerized chloride ion-doped PEDOT nanoparticles according to claim 1, characterized in that: The micelle solution is formed by mixing dodecyltrimethylammonium chloride and water in a ratio of (2-6.5) g:400 mL.

3. The method for preparing emulsion-polymerized chloride ion-doped PEDOT nanoparticles according to claim 1, characterized in that: The molar ratio of the EDOT to the dodecyltrimethylammonium chloride is 1:(0.25-0.7).

4. The method for preparing emulsion-polymerized chloride ion-doped PEDOT nanoparticles according to claim 3, characterized in that: The molar ratio of the EDOT to the dodecyltrimethylammonium chloride is 1:(0.5-0.65).

5. The method for preparing emulsion-polymerized chloride ion-doped PEDOT nanoparticles according to claim 1, characterized in that: The stirring speed is 550-800 rpm.

6. The method for preparing emulsion-polymerized chloride ion-doped PEDOT nanoparticles according to claim 1, characterized in that: The oxidant solution is a 1.4-3.0 mol / L ferric chloride solution; and / or, Calculated based on the total amount of water in the micelle solution and the oxidant solution, the concentration of dodecyltrimethylammonium chloride relative to the total amount of water is 35-46 mmol / L.

7. The method for preparing chloride ion-doped PEDOT nanoparticles by emulsion polymerization according to claim 1, characterized in that: The molar ratio of the EDOT to the oxidant is 1:(4-8).

8. The method for preparing emulsion-polymerized chloride ion-doped PEDOT nanoparticles according to claim 1, characterized in that: The emulsion polymerization reaction is carried out at 15-40° C. for 72-168 hours.

9. PEDOT nanoparticles prepared by the preparation method according to any one of claims 1 to 8.

10. Use of the PEDOT nanoparticles according to claim 9 as a conductive material.

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