A method for preparing high-conversion-rate PEDOT powder

Abstract

This invention belongs to the field of conductive polymer technology, and more specifically, relates to a method for preparing high-conversion PEDOT powder. Using 3-HPS as an additive and adjusting the dosage of 3-HPS, high-conductivity, high-conversion, and high-purity PEDOT powder can be prepared. This method is simple to operate, requires a limited number of raw materials, and has low energy consumption. Furthermore, the preparation method is highly reproducible, resulting in PEDOT products with stable performance and high conductivity, making it commercially viable for industrial mass production.

Description

Technical Field

[0001] The present invention belongs to the technical field of conductive polymers, and more specifically, relates to a method for preparing high-conversion-rate PEDOT powder. Background Art

[0002] In 1988, Bayer of Germany submitted an invention patent for EDOT (3,4-ethylenedioxythiophene), and the performance of polythiophene was officially broken through. The PEDOT obtained by Bayer through the polymerization reaction of ferric chloride showed unparalleled high conductivity and stability. Subsequently, Bayer combined the polyanion corresponding to water-based polystyrene sulfonic acid (PSS) with the positively charged doped PEDOT counterion to form a PEDOT:PSS complex, which solved the solubility problem of PEDOT and opened the door to the commercialization of PEDOT. Nowadays, PEDOT and its derivative functional materials have emerged in large numbers and are widely used in hole transport layers in solar cells and OLEDs, biomedicine, thermoelectric materials, electrode materials and supercapacitors, electromagnetic protection and antistatic materials.

[0003] Currently, commercial PEDOT products primarily consist of PEDOT:PSS inks, which suffer from limitations such as limited usage, low conductivity, poor processability, and a limited supply of effective conductive components. Compared to inks, conductive powders offer advantages such as higher conductivity, wider application range, enhanced processability, and simpler storage, offering significant commercial potential. However, powder preparation still presents challenges such as unstable conductivity, low conversion rates, complex raw material usage, and immature manufacturing processes. Summary of the Invention

[0004] To address the shortcomings of the existing technology, the present invention provides a method for preparing PEDOT powder with high conversion rate and conductivity. By introducing trihydroxypropyl sulfonic acid (3-HPS) as an additive during the aqueous suspension precipitation polymerization process, the present invention solves the technical problems existing in the existing PEDOT powder preparation methods, such as a large number of impurities, complex production process, unstable conductivity, and low PEDOT conversion rate.

[0005] To achieve the above object, the present invention provides a method for preparing PEDOT powder, comprising the following steps:

[0006] (1) mixing EDOT monomer, 3-HPS additive and water and stirring and dispersing the mixture to obtain an EDOT dispersion;

[0007] (2) The EDOT dispersion of step (1) is mixed with an aqueous solution of ferric chloride as an oxidant, and the mixture is stirred and reacted at room temperature for 20-30 hours, and then heated to 48-55° C. and stirred and reacted for 70-80 hours. After the reaction, the solid and liquid are separated, and the separated solid phase is washed and dried to obtain the PEDOT powder.

[0008] Preferably, the molar ratio of the EDOT monomer to the 3-HPS additive in step (1) is 1:(0.1-1.2).

[0009] Preferably, the concentration of EDOT in the EDOT dispersion in step (1) is 1-5 wt %.

[0010] Preferably, the molar ratio of the oxidant ferric chloride to the EDOT monomer in step (2) is (2-4):1, more preferably (2-3):1.

[0011] Preferably, in step (2), the aqueous solution of ferric chloride is added to the EDOT dispersion at one time, or the aqueous solution of ferric chloride is added dropwise to the EDOT dispersion.

[0012] Preferably, in step (2), the EDOT dispersion of step (1) is mixed with an aqueous solution of ferric chloride as an oxidant, and the mixture is stirred and reacted at room temperature for 20-30 hours, and then heated to 48-52° C. and stirred and reacted for 70-80 hours.

[0013] Preferably, in step (2), the solid phase obtained by solid-liquid separation is washed alternately in water and ethanol.

[0014] Preferably, the drying in step (2) is freeze-drying for 36-72 hours.

[0015] Preferably, the conductivity of the PEDOT powder is between 10 0 S / cm order of magnitude; its conversion rate is greater than 93%.

[0016] In general, the above technical solutions conceived by the present invention have the following technical advantages compared with the existing technology:

[0017] 1. The present invention proposes a method for preparing PEDOT powder by a water-based suspension precipitation reaction. By introducing a 3-HPS additive during the preparation process, the conversion rate of the reaction can be significantly improved compared to when no 3-HPS additive is added.

[0018] 2. The PEDOT powder prepared by the preparation method of the present invention has high conductivity, which can reach 10 0 Since 3-HPS is a small molecule additive that is easily soluble in water, it is easy to remove during the cleaning process, resulting in a higher purity of the product powder.

[0019] 3. The present invention describes a method for suspension precipitation polymerization of PEDOT, using 3-HPS as an additive. By adjusting the 3-HPS dosage and controlling the reaction temperature, high-conductivity, high-conversion, and high-purity PEDOT powder can be produced. This method is simple to operate, requires a limited number of raw materials, and consumes relatively low energy. Furthermore, the method is highly reproducible, resulting in PEDOT products with stable performance and high conductivity, making it commercially viable for industrial mass production. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 This is the reaction scheme for the PEDOT polymerization of the present invention;

[0021] Figure 2 1 is a process flow chart of the preparation method of the present invention;

[0022] Figure 3 This is a photo of the PEDOT powder prepared in Example 1 of the present invention;

[0023] Figure 4 X-ray photoelectron spectra of the PEDOT products prepared in Comparative Example 1 and Examples 1 to 3 of the present invention. DETAILED DESCRIPTION

[0024] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention will be further described in detail below with reference to the accompanying drawings and 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.

[0025] In the description of the present invention, it should be understood that the terms "first" and "second" are used for descriptive purposes only and should not be understood to indicate or imply relative importance or implicitly specify the number of the technical features indicated. Therefore, a feature specified as "first" or "second" may explicitly or implicitly include one or more of the features. In the description of the present invention, "plurality" means two or more, unless otherwise specifically defined.

[0026] Additionally, references throughout this specification to "one embodiment," "one embodiment," "an example," or similar language indicate that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment of the present invention. Thus, appearances of the phrase "in one embodiment," "in one embodiment," and similar language throughout this specification may, but do not necessarily, all refer to the same embodiment.

[0027] The present invention provides a method for preparing PEDOT powder, comprising the following steps:

[0028] (1) mixing EDOT monomer, 3-HPS additive and water and stirring and dispersing the mixture to obtain an EDOT dispersion;

[0029] (2) The EDOT dispersion of step (1) is mixed with an aqueous solution of ferric chloride as an oxidant, and the mixture is stirred and reacted at room temperature for 20-30 hours, and then heated to 48-55° C. and stirred and reacted for 70-80 hours. After the reaction, the solid and liquid are separated, and the separated solid phase is washed and dried to obtain the PEDOT powder.

[0030] In some embodiments, the molar ratio of the EDOT monomer to the 3-HPS additive in step (1) is 1:(0.1-1.2), preferably 1:(0.2-1.1). The concentration of EDOT in the EDOT dispersion in step (1) is 1-5 wt%. The molar ratio of the oxidant ferric chloride to the EDOT monomer in step (2) is (2-4):1, preferably (2-3):1, and more preferably 2.5:1. The ferric chloride described in the present invention can be ferric chloride hexahydrate or anhydrous ferric chloride.

[0031] In some embodiments, in step (2), the aqueous solution of ferric chloride is added to the EDOT dispersion all at once, or the aqueous solution of ferric chloride is added dropwise to the EDOT dispersion. In a preferred embodiment, the oxidizing agent ferric chloride solution is added dropwise within 2 hours; at a lower addition temperature, the addition rate can be appropriately increased.

[0032] During the dropwise addition of the oxidizing agent ferric chloride solution, the temperature in the reactor is generally controlled at around 25°C and not lower than 10°C. Of course, in some cases, the temperature in the reactor can also be appropriately lowered (not lower than 10°C) to reduce the polymerization rate of EDOT during the dropwise addition process and prevent negative effects such as uneven particle size caused by localized polymerization.

[0033] In a preferred embodiment, in step (2), the EDOT dispersion of step (1) is mixed with an aqueous solution of ferric chloride as an oxidant, and the mixture is stirred at room temperature (20-30° C.) for 20-30 hours, and then heated to 48-52° C. for 70-80 hours.

[0034] In some embodiments, the solid phase obtained by solid-liquid separation in step (2) is washed alternately in water and ethanol. The drying is freeze-drying for 36-72 hours.

[0035] In the preparation method of the present invention, no additives other than 3-HPS are added, and the conductivity of the prepared PEDOT powder is between 10 0 S / cm order of magnitude; its conversion rate is greater than 93%.

[0036] PEDOT powder is prepared based on water-based suspended precipitation polymerization. The higher the conversion rate of the EDOT monomer polymerization reaction, the higher the production efficiency. It has important commercial significance for the production of PEDOT. Therefore, the pursuit of higher conversion rate has become one of the important goals of PEDOT production. However, the highest level of conversion rate in the preparation process of the traditional method is about 90%, but it is difficult to further improve the reaction conversion rate. The present invention accidentally discovered that the introduction of 3-HPS additives in the precipitation polymerization process can increase its conversion rate to 98.7%, which is close to 100%. Moreover, the conductivity of the prepared PEDOT powder is high, on the order of 10 0 S / cm.

[0037] In some embodiments, the water of the present invention is one or more of ultrapure water, deionized water, double-distilled water, pure water, and distilled water.

[0038] The present invention describes a method for suspension precipitation polymerization of PEDOT, which introduces a 3-HPS additive and adjusts the dosage of 3-HPS to produce PEDOT powder with high conductivity and high conversion. This method is simple to operate, requires fewer raw materials, and consumes less energy. Furthermore, the method is highly reproducible, resulting in PEDOT products with stable performance and high conductivity, making it commercially viable for industrial mass production.

[0039] During the preparation method of the present invention, as the reaction proceeds, the solid product increases, the solid content of the system rises, and the system becomes viscous and fluidity deteriorates, hindering the continued reaction. It is inferred that the additive 3-HPS may play a certain dispersing role, preventing the newly generated PEDOT solid particles from agglomerating to form large particles, significantly improving the fluidity of the reaction system, reducing the viscosity of the reaction system, avoiding the adverse effects of excessive viscosity on the polymerization process, and enhancing the reaction degree of PEDOT, PEDOT conversion rate, and production efficiency. At the same time, the 3-HPS additive can also effectively reduce the particle size of PEDOT particles, making the particles finer, the particle size distribution narrower, and the contact between them closer, thereby improving their conductivity. Furthermore, because the 3-HPS additive is a small molecule, it can be easily cleaned and removed from the product, resulting in a higher purity of the PEDOT powder product.

[0040] The present invention can stably prepare a product with a conductivity of 10 0 S / cm order of PEDOT powder, and its conversion rate increased to a great extent.

[0041] In some embodiments, such as Figure 1 and Figure 2 As shown, the preparation method specifically comprises the following steps:

[0042] S1. Dispersion of EDOT: A certain amount of distilled water was added to a reaction vessel, and EDOT monomer and a certain amount of 3-HPS were added. The EDOT monomer was fully dispersed by continuous stirring to obtain a slightly yellowish milky white EDOT dispersion.

[0043] S2. Adding ferric chloride dropwise: Take a certain amount of ferric chloride hexahydrate and dissolve it in a certain amount of distilled water. Keep stirring in the reaction container and add the ferric chloride solution to the reaction container at room temperature (25°C).

[0044] S3. Polymerization of EDOT: Keep stirring continuously and react at room temperature for 24 hours after the addition is completed; then raise the temperature to 50°C and react for 72 hours.

[0045] S4. Collection, Washing, and Drying of PEDOT: After the reaction is complete, the reaction liquid is separated into solid and liquid, leaving a solid product. The product is rinsed several times with distilled water and anhydrous ethanol, alternating between rinses. After rinsing, the solid product is dispersed in distilled water or anhydrous ethanol and washed several times using ultrasonic heating until the filtrate is clear and transparent. After washing, the solid product is freeze-dried to obtain PEDOT powder.

[0046] In some embodiments, step S4 involves repeatedly rinsing the product several times with distilled water and anhydrous ethanol, alternating between rinses. After rinsing, the solid product is thoroughly dispersed in anhydrous ethanol and the PEDOT solid is washed using ultrasonic heating, with each ultrasonic cleaning process set at 50-60°C for 20-30 minutes. After ultrasonic cleaning, the PEDOT solid product is separated by filtration and the cleaning process is repeated several times. The product is then rinsed several times with distilled water, alternating between ethanol and distilled water. After the cleaning process is complete, the solid product is placed in a freeze-drying oven and freeze-dried for 48-72 hours to obtain PEDOT powder.

[0047] The PEDOT powder prepared by the preparation method of the present invention has high electrical conductivity. Compared with traditional water-based precipitation polymerization, the PEDOT powder prepared by this method has higher purity, higher effective conductive components, and good processability.

[0048] The following are specific embodiments:

[0049] Example 1

[0050] S1. Dissolution of EDOT: Add 5g of EDOT and 1.68g of 3-HPS (0.34 times the molar ratio of EDOT) to a 250mL Erlenmeyer flask. Pour in a sufficient amount of distilled water to prepare 120mL of EDOT dispersion. Place the flask in a water bath with a magnetic stirrer and stir for 1 hour to obtain a uniformly dispersed EDOT dispersion.

[0051] S2. Adding ferric chloride solution dropwise: Take 23.76 g of ferric chloride hexahydrate, dissolve it in a certain amount of distilled water to prepare 130 mL of ferric chloride aqueous solution, and add it dropwise to the reaction solution at room temperature (around 25° C.) within 2 hours.

[0052] S3. Polymerization of EDOT: After the ferric chloride solution was added dropwise, the reaction was maintained at room temperature (25°C, the same below) for 24 hours. After reacting at room temperature for 24 hours, the reaction solution was raised from room temperature to 50°C, and then reacted for 72 hours.

[0053] S4. Collection, Washing, and Drying of PEDOT: After the reaction is complete, filter the reaction mixture using a G6 fritted funnel to obtain a bluish-black PEDOT solid. After washing the product several times with alternating distilled water and anhydrous ethanol, transfer the solid PEDOT to a 500 mL beaker and add 200 mL of anhydrous ethanol. Ultrasonic cleaning is performed at 60°C for 30 minutes. After completion, filter the solid product using a fritted funnel. Continue ultrasonic cleaning several times with alternating anhydrous ethanol and distilled water until the filtrate is clear and transparent.

[0054] After washing, the solid product was placed in a freeze drying oven and freeze-dried for 72 hours. After drying, the obtained PEDOT solid product was placed in an agate grinder and crushed into fine powder, thus obtaining PEDOT powder (such as Figure 3 shown).

[0055] Prepared PEDOT powder test:

[0056] 1. PEDOT conductivity test method: Pour a certain amount of PEDOT powder into a tableting mold, pressurize to 40mPa, and maintain pressure for 30 minutes. Then remove the PEDOT sheet, measure its thickness, and test its conductivity using a four-probe resistivity tester (Mitsubishi MCP-TP610, MCP-TP06P, and RMH311). The test results show that the conductivity of the PEDOT powder is 6.763×10 0 S / cm.

[0057] 2. PEDOT conversion rate test method: The conversion rate calculation formula is as follows

[0058]

[0059] Where: m PEDOT is the mass of the collected product; m EDOT is the mass of the added EDOT monomer. After drying, the PEDOT solid was collected and the conversion rate of PEDOT was calculated according to this formula to be 93.4%.

[0060] Example 2

[0061] S1. Dissolution of EDOT: Add 5 g of EDOT and 3.30 g of 3-HPS (0.67 times the molar ratio of EDOT) to a 250 mL Erlenmeyer flask. Pour in a sufficient amount of distilled water to prepare 120 mL of EDOT dispersion. Place the flask in a water bath with a magnetic stirrer and stir for 1 hour to obtain a uniformly dispersed EDOT dispersion.

[0062] S2. Adding ferric chloride solution dropwise: Take 23.76 g of ferric chloride hexahydrate, dissolve it in a certain amount of distilled water to prepare 130 mL of ferric chloride aqueous solution, and add it dropwise to the reaction solution at room temperature (around 25° C.) within 2 hours.

[0063] S3. Polymerization of EDOT: After the ferric chloride solution is added dropwise, the reaction is maintained at room temperature for 24 hours. After reacting at room temperature for 24 hours, the reaction solution is heated from room temperature to 50°C, and then reacted at 50°C for 72 hours.

[0064] S4. Collection, Washing, and Drying of PEDOT: After the reaction is complete, filter the reaction mixture using a G6 fritted funnel to obtain a bluish-black PEDOT solid. After washing the product several times with alternating distilled water and anhydrous ethanol, transfer the solid PEDOT to a 500 mL beaker and add 200 mL of anhydrous ethanol. Ultrasonic cleaning is performed at 60°C for 30 minutes. After completion, filter the solid product using a fritted funnel. Continue ultrasonic cleaning several times with alternating anhydrous ethanol and distilled water until the filtrate is clear and transparent.

[0065] After washing, the solid product was placed in a freeze drying oven and freeze-dried for 72 hours. After drying, the obtained PEDOT solid product was placed in an agate mill and crushed into fine powder, thus obtaining PEDOT powder.

[0066] Prepared PEDOT powder test:

[0067] 1. PEDOT conductivity test method: Pour a certain amount of PEDOT powder into a tableting mold, pressurize to 40mPa, and maintain pressure for 30 minutes. Then remove the PEDOT sheet, measure its thickness, and test its conductivity using a four-probe resistivity tester (Mitsubishi MCP-TP610, MCP-TP06P, and RMH311). The test results show that the conductivity of the PEDOT powder is 5.091×10 0 S / cm.

[0068] 2. PEDOT conversion rate test method: The conversion rate calculation formula is as follows

[0069]

[0070] Where: m PEDOT is the mass of the collected product; m EDOT is the mass of the added EDOT monomer. After drying, the PEDOT solid was collected and the conversion rate of PEDOT was calculated according to this formula to be 95.8%.

[0071] Example 3

[0072] S1. Dissolution of EDOT: Add 5g of EDOT and 5.18g of 3-HPS (1.05 times the molar ratio of EDOT) to a 250mL Erlenmeyer flask. Pour in a sufficient amount of distilled water to prepare 120mL of EDOT dispersion. Place the flask in a water bath with a magnetic stirrer and stir for 1 hour to obtain a uniformly dispersed EDOT dispersion.

[0073] S2. Adding ferric chloride solution dropwise: Take 23.76 g of ferric chloride hexahydrate, dissolve it in a certain amount of distilled water to prepare 130 mL of ferric chloride aqueous solution, and add it dropwise to the reaction solution at room temperature (around 25° C.) within 2 hours.

[0074] S3. Polymerization of EDOT: After the ferric chloride solution is added dropwise, the reaction is maintained at room temperature for 24 hours. After reacting at room temperature for 24 hours, the reaction solution is heated from room temperature to 50°C, and then reacted at 50°C for 72 hours.

[0075] S4. Collection, Washing, and Drying of PEDOT: After the reaction is complete, filter the reaction mixture using a G6 fritted funnel to obtain a bluish-black PEDOT solid. After washing the product several times with alternating distilled water and anhydrous ethanol, transfer the solid PEDOT to a 500 mL beaker and add 200 mL of anhydrous ethanol. Ultrasonic cleaning is performed at 60°C for 30 minutes. After completion, filter the solid product using a fritted funnel. Continue ultrasonic cleaning several times with alternating anhydrous ethanol and distilled water until the filtrate is clear and transparent.

[0076] After washing, the solid product was placed in a freeze drying oven and freeze-dried for 72 hours. After drying, the obtained PEDOT solid product was placed in an agate mill and crushed into fine powder, thus obtaining PEDOT powder.

[0077] Prepared PEDOT powder test:

[0078] 1. PEDOT conductivity test method: Pour a certain amount of PEDOT powder into a tableting mold, pressurize to 40mPa, and maintain pressure for 30 minutes. Then remove the PEDOT sheet, measure its thickness, and test its conductivity using a four-probe resistivity tester (Mitsubishi MCP-TP610, MCP-TP06P, and RMH311). The test results show that the conductivity of the PEDOT powder is 5.005×10 0 S / cm.

[0079] 2. PEDOT conversion rate test method: The conversion rate calculation formula is as follows

[0080]

[0081] Where: m PEDOT is the mass of the collected product; m EDOT is the mass of the added EDOT monomer. After drying, the PEDOT solid was collected and the conversion rate of PEDOT was calculated according to this formula to be 97.8%.

[0082] Comparative Example 1

[0083] S1. Dissolve EDOT: Add 5 g of EDOT to a 250 mL Erlenmeyer flask and add a sufficient amount of distilled water to prepare 120 mL of EDOT dispersion. Place the flask in a water bath with a magnetic stirrer and stir for 1 hour to obtain a uniformly dispersed EDOT dispersion.

[0084] S2. Adding ferric chloride solution dropwise: Take 23.76 g of ferric chloride hexahydrate, dissolve it in a certain amount of distilled water to prepare 130 mL of ferric chloride aqueous solution, and add it dropwise to the reaction solution at room temperature (around 25° C.) within 2 hours.

[0085] S3. Polymerization of EDOT: After the ferric chloride solution is added dropwise, the reaction is maintained at room temperature for 24 hours. After reacting at room temperature for 24 hours, the reaction solution is heated from room temperature to 50°C, and then reacted at 50°C for 72 hours.

[0086] S4. Collection, Washing, and Drying of PEDOT: After the reaction is complete, filter the reaction mixture using a G6 fritted funnel to obtain a bluish-black PEDOT solid. After washing the product several times with alternating distilled water and anhydrous ethanol, transfer the solid PEDOT to a 500 mL beaker and add 200 mL of anhydrous ethanol. Ultrasonic cleaning is performed at 60°C for 30 minutes. After completion, filter the solid product using a fritted funnel. Continue ultrasonic cleaning several times with alternating anhydrous ethanol and distilled water until the filtrate is clear and transparent.

[0087] After washing, the solid product was placed in a freeze drying oven and freeze-dried for 72 hours. After drying, the obtained PEDOT solid product was placed in an agate mill and crushed into fine powder, thus obtaining PEDOT powder.

[0088] Prepared PEDOT powder test:

[0089] 1. PEDOT conductivity test method: Pour a certain amount of PEDOT powder into a tableting mold, pressurize to 40mPa, and maintain pressure for 30 minutes. Then remove the PEDOT sheet, measure its thickness, and test its conductivity using a four-probe resistivity tester (Mitsubishi MCP-TP610, MCP-TP06P, and RMH311). The test results show that the conductivity of the PEDOT powder is 6.805×10 0 S / cm.

[0090] 2. PEDOT conversion rate test method: The conversion rate calculation formula is as follows

[0091]

[0092] Where: m PEDOT is the mass of the collected product; m EDOT is the mass of the added EDOT monomer. After drying, the PEDOT solid was collected and the conversion rate of PEDOT was calculated according to this formula to be 92%.

[0093] Comparative Example 2

[0094] S1. Dissolution of EDOT: Add 5g of EDOT and 1.68g of 3-HPS (0.34 times the molar ratio of EDOT) to a 250mL Erlenmeyer flask. Pour in a sufficient amount of distilled water to prepare 120mL of EDOT dispersion. Place the flask in a water bath with a magnetic stirrer and stir for 1 hour to obtain a uniformly dispersed EDOT dispersion.

[0095] S2. Addition of ferric chloride: 23.76 g of ferric chloride hexahydrate was dissolved in a certain amount of distilled water to prepare 130 mL of ferric chloride aqueous solution, which was added dropwise to the reaction solution at room temperature (25° C.) over 2 hours.

[0096] S3. Polymerization of EDOT: After the ferric chloride solution is added dropwise, the reaction is maintained at room temperature for 24 hours. After reacting at room temperature for 24 hours, the reaction solution is heated from room temperature to 40°C, and then reacted at 40°C for 24 hours. After reacting at 40°C for 24 hours, the reaction solution is heated from 40°C to 50°C, and then reacted at 50°C for 48 hours.

[0097] S4. Collection, Washing, and Drying of PEDOT: After the reaction is complete, filter the reaction mixture using a G6 fritted funnel to obtain a bluish-black PEDOT solid. After washing the product several times with alternating distilled water and anhydrous ethanol, transfer the solid PEDOT to a 500 mL beaker and add 200 mL of anhydrous ethanol. Ultrasonic cleaning is performed at 60°C for 30 minutes. After completion, filter the solid product using a fritted funnel. Continue ultrasonic cleaning several times with alternating anhydrous ethanol and distilled water until the filtrate is clear and transparent.

[0098] After washing, the solid product was placed in a freeze drying oven and freeze-dried for 72 hours. After drying, the obtained PEDOT solid product was placed in an agate mill and crushed into fine powder, thus obtaining PEDOT powder.

[0099] Prepared PEDOT powder test:

[0100] 1. PEDOT conductivity test method: Pour a certain amount of PEDOT powder into a tableting mold, pressurize to 40mPa, and maintain pressure for 30 minutes. Then remove the PEDOT sheet, measure its thickness, and test its conductivity using a four-probe resistivity tester (Mitsubishi MCP-TP610, Mitsubishi MCP-TP06P, and Mitsubishi RMH311). The test results show that the conductivity of the PEDOT powder is 2.543×10 0 S / cm.

[0101] 2. PEDOT conversion rate test method: The conversion rate calculation formula is as follows

[0102]

[0103] Where: m PEDOT is the mass of the collected product; m EDOT is the mass of the added EDOT monomer. After drying, the PEDOT solid was collected and the conversion rate of PEDOT was calculated according to this formula to be 79.2%.

[0104] Comparative Example 3

[0105] S1. Dissolution of EDOT: Add 5g of EDOT and 3.30g of 3-HPS (0.67 times the molar ratio of EDOT) to a 250mL Erlenmeyer flask. Pour in a sufficient amount of distilled water to prepare 120mL of EDOT dispersion. Place the flask in a water bath with a magnetic stirrer and stir for 1 hour to obtain a uniformly dispersed EDOT dispersion.

[0106] S2. Addition of ferric chloride: 23.76 g of ferric chloride hexahydrate was dissolved in a certain amount of distilled water to prepare 130 mL of ferric chloride aqueous solution, which was added dropwise to the reaction solution at room temperature (25° C.) over 2 hours.

[0107] S3. Polymerization of EDOT: After the ferric chloride solution is added dropwise, the reaction is maintained at room temperature for 24 hours. After reacting at room temperature for 24 hours, the reaction solution is heated from room temperature to 40°C, and then reacted at 40°C for 24 hours. After reacting at 40°C for 24 hours, the reaction solution is heated from 40°C to 50°C, and then reacted at 50°C for 48 hours.

[0108] S4. Collection, Washing, and Drying of PEDOT: After the reaction is complete, filter the reaction mixture using a G6 fritted funnel to obtain a bluish-black PEDOT solid. After washing the product several times with alternating distilled water and anhydrous ethanol, transfer the solid PEDOT to a 500 mL beaker and add 200 mL of anhydrous ethanol. Ultrasonic cleaning is performed at 60°C for 30 minutes. After completion, filter the solid product using a fritted funnel. Continue ultrasonic cleaning several times with alternating anhydrous ethanol and distilled water until the filtrate is clear and transparent.

[0109] After washing, the solid product was placed in a freeze drying oven and freeze-dried for 72 hours. After drying, the obtained PEDOT solid product was placed in an agate mill and crushed into fine powder, thus obtaining PEDOT powder.

[0110] Prepared PEDOT powder test:

[0111] 1. PEDOT conductivity test method: Pour a certain amount of PEDOT powder into a tableting mold, pressurize to 40mPa, and maintain pressure for 30 minutes. Then remove the PEDOT sheet, measure its thickness, and test its conductivity using a four-probe resistivity tester (Mitsubishi MCP-TP610, Mitsubishi MCP-TP06P, and Mitsubishi RMH311 probe calibrator). The test results show that the conductivity of the PEDOT powder is 2.234×10 0 S / cm.

[0112] 2. PEDOT conversion rate test method: The conversion rate calculation formula is as follows

[0113]

[0114] Where: m PEDOT is the mass of the collected product; m EDOT is the mass of the added EDOT monomer. After drying, the PEDOT solid was collected and the conversion rate of PEDOT was calculated to be 81.4% according to this formula.

[0115] Comparative Example 4

[0116] S1. Dissolve EDOT: Add 5g of EDOT to a 250mL Erlenmeyer flask and add a sufficient amount of distilled water to prepare 120mL of EDOT dispersion. Place the flask in a water bath with a magnetic stirrer and stir for 1 hour to obtain a uniformly dispersed EDOT dispersion.

[0117] S2. Addition of ferric chloride: 23.76 g of ferric chloride hexahydrate was dissolved in a certain amount of distilled water to prepare 130 mL of ferric chloride aqueous solution, which was added dropwise to the reaction solution at room temperature (25° C.) over 2 hours.

[0118] S3. Polymerization of EDOT: After the addition of ferric chloride solution is completed, the reaction is maintained at room temperature for 24 hours; after reacting at room temperature for 24 hours, the reaction solution is raised from room temperature to 40°C, and then reacted at 40°C for 24 hours; after reacting at 40°C for 24 hours, the reaction solution is raised from 40°C to 50°C, and then reacted at 50°C for 48 hours.

[0119] S4. Collection, Washing, and Drying of PEDOT: After the reaction is complete, filter the reaction mixture using a G6 fritted funnel to obtain a bluish-black PEDOT solid. After washing the product several times with alternating distilled water and anhydrous ethanol, transfer the solid PEDOT to a 500 mL beaker and add 200 mL of anhydrous ethanol. Ultrasonic cleaning is performed at 60°C for 30 minutes. After completion, filter the solid product using a fritted funnel. Continue ultrasonic cleaning several times with alternating anhydrous ethanol and distilled water until the filtrate is clear and transparent.

[0120] After washing, the solid product was placed in a freeze drying oven and freeze-dried for 72 hours. After drying, the obtained PEDOT solid product was placed in an agate mill and crushed into fine powder, thus obtaining PEDOT powder.

[0121] Prepared PEDOT powder test:

[0122] 1. PEDOT conductivity test method: Pour a certain amount of PEDOT powder into a tableting mold, pressurize to 40mPa, and maintain pressure for 30 minutes. Then remove the PEDOT sheet, measure its thickness, and test its conductivity using a four-probe resistivity tester (Mitsubishi MCP-TP610, Mitsubishi MCP-TP06P, and Mitsubishi RMH311 probe calibrator). The test results show that the conductivity of the PEDOT powder is 5.189×10 0 S / cm.

[0123] 2. PEDOT conversion rate test method: The conversion rate calculation formula is as follows

[0124]

[0125] Where: m PEDOT is the mass of the collected product; m EDOT is the mass of the added EDOT monomer. After drying, the PEDOT solid was collected and the conversion rate of PEDOT was calculated according to this formula to be 60.8%.

[0126] The conductivity and conversion rate results of PEDOT powders prepared under different conditions in different examples and comparative examples are listed in Table 1.

[0127] As can be seen from Table 1, compared with Example 1, Example 2, Example 3 and Comparative Example 1, after adding 3-HPS, the conductivity remains almost unchanged and is maintained at 10 0 S / cm order of magnitude, with the increase of the addition amount of 3-HPS, the conversion rate can be increased to 98.7% at most, which is close to 100%.

[0128] During the experiment, we also tested the possibility of lowering the reaction temperature in order to slow down the reaction rate and obtain higher conductivity, such as Comparative Examples 2, 3, and 4 in Table 1. The temperature of some of the reactions was lowered to 40°C. The results showed that the temperature reduction was not conducive to the reaction, and the conductivity could be maintained at 10 0 S / cm order of magnitude, but the conversion rate dropped significantly, and its industrial production significance is far less than that of the embodiment.

[0129] Table 1 Conductivity and conversion rate results of PEDOT powders prepared in different examples and comparative examples

[0130]

[0131] In addition, if Figure 4 As shown (content a, content b, content c, and content d correspond to comparative example 1, example 1, example 2, and example 3, respectively), the sulfur content of the products prepared in the different examples and comparative examples was analyzed using an X-ray photoelectron spectrometer (ESCALAB 250Xi, Thermo Scientific). The sulfur peak of the thiophene ring on the main chain of the PEDOT product should appear near 164 eV, which is consistent with the measured spectrum. The sulfur peak of the sulfonate group in 3-HPS should appear near 168.1 eV, but no obvious peak appears near 168.1 eV in the spectrum. This indicates that the PEDOT products prepared in the examples of the present invention do not contain sulfonate groups and that the residual 3-HPS impurity can be relatively thoroughly removed through cleaning.

[0132] It will be easily understood by those skilled in the art that the above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements 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 PEDOT powder, characterized in that: The steps include: (1) Mixing EDOT monomer, 3-HPS additive and water and stirring to disperse the mixture to obtain an EDOT dispersion; the molar ratio of the EDOT monomer to the 3-HPS additive is 1:(0.1-1.2); the concentration of EDOT in the EDOT dispersion is 1-5 wt%; (2) The EDOT dispersion of step (1) is mixed with an aqueous solution of ferric chloride as an oxidant, and the mixture is stirred and reacted at room temperature for 20-30 hours, and then heated to 48-55° C. and stirred and reacted for 70-80 hours. After the reaction, the solid and liquid are separated, and the separated solid phase is washed and dried to obtain the PEDOT powder.

2. The preparation method according to claim 1, wherein The molar ratio of the oxidant ferric chloride to the EDOT monomer in step (2) is (2-4):

1.

3. The preparation method according to claim 1, wherein The molar ratio of the oxidant ferric chloride to the EDOT monomer in step (2) is (2-3):

1.

4. The preparation method according to claim 1, wherein Step (2) adding the aqueous solution of ferric chloride into the EDOT dispersion at one time, or adding the aqueous solution of ferric chloride dropwise into the EDOT dispersion.

5. The preparation method according to claim 1, wherein Step (2) mixing the EDOT dispersion of step (1) with an aqueous solution of ferric chloride as an oxidant, stirring and reacting at room temperature for 20-30 hours, and then heating to 48-52° C. and stirring and reacting for 70-80 hours.

6. The preparation method according to claim 1, wherein Step (2) The solid phase obtained by solid-liquid separation is washed alternately in water and ethanol.

7. The preparation method according to claim 1, wherein The drying in step (2) is freeze drying for 36-72 hours.

8. The preparation method according to claim 1, wherein The conductivity of the PEDOT powder is 10 0 S / cm order of magnitude; its conversion rate is greater than 93%.

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