CN107189083B

CN107189083B - Conductive polymer PEDOT organic dispersion system and preparation method thereof

Info

Publication number: CN107189083B
Application number: CN201710474630.6A
Authority: CN
Inventors: 张灵志; 何嘉荣; 汪靖伦; 苏静
Original assignee: Guangzhou Institute of Energy Conversion of CAS
Current assignee: Guangzhou Institute of Energy Conversion of CAS
Priority date: 2017-06-21
Filing date: 2017-06-21
Publication date: 2019-12-20
Anticipated expiration: 2037-06-21
Also published as: CN107189083A

Abstract

The invention discloses a conductive polymer PEDOT organic dispersion system, which comprises an organic solvent with strong polarity and high dielectric constant and PEDOT, wherein the dispersion system obtained by selecting a proper organic solvent system and a proper surfactant has good film-forming property and chemical stability, can be dispersed in the organic system in a colloid form for a long time, does not generate sedimentation and stably exists, has excellent electronic conductivity, has very important practical significance for solving the practical application of the conductive polymer of a non-aqueous dispersion system, can promote the further development of the high-conductivity PEDOT organic dispersion system, and has important significance for promoting the development of strategic emerging industries of organic electronic equipment, novel light emitting and display industries, even chargeable and dischargeable polymer batteries, Organic Light Emitting Diodes (OLEDs) and the like, and has wide market prospect.

Description

Conductive polymer PEDOT organic dispersion system and preparation method thereof

The technical field is as follows:

the invention relates to the technical field of conductive high-molecular functional materials, in particular to a conductive polymer PEDOT organic dispersion system and a preparation method thereof.

Background art:

conductive polymers have attracted great interest to scientists since the discovery of conductive polyacetylene. Common conductive polymers include Polyacetylene (PA), polythiophene (PTh), Polyaniline (PANI), polypyrrole (PPy), poly (3, 4-ethylenedioxythiophene) (PEDOT) and the like, and due to the fact that the common conductive polymers have a special pi-pi conjugated structure, regular chain orientation and excellent physical and chemical properties, the common conductive polymers are widely researched and applied to the fields of sensors, electrochromism, antistatic coatings, supercapacitors, Organic Light Emitting Diodes (OLEDs) and the like. Among them, PEDOT is a system dispersed in a colloidal form, which attracts more and more researchers' attention due to its high conductivity, good chemical stability, film transparency, environmental stability, and the like, and shows a wide application prospect in the fields of solid electrolyte capacitor cathode materials, plastic antistatic coatings, sensor materials, chargeable and dischargeable polymer batteries, and the like. However, since the PEDOT main chain has a strong pi-pi conjugated rigid structure and strong pi electronic interaction exists between different chains, the PEDOT main chain is difficult to dissolve and stably disperse in water or an organic solvent, and processing and treatment are difficult. The use of PEDOT as a single component is therefore greatly limited. At present, the main widely used is an aqueous dispersion of PEDOT/poly (styrenesulfonic acid) (PEDOT/PSS) complex. In a PEDOT/PSS system, PSS serving as polyelectrolyte can be well combined and doped with PEDOT, and the sulfonic acid group of the PSS serving as a side group can enable the PEDOT to be well dispersed in an aqueous medium, so that the processability of the PEDOT is greatly improved, and the practical application of the PEDOT is further expanded.

However, the hydrophilic nature of aqueous PEDOT/PSS dispersions also limits the use of PEDOT in certain industrial applications. For example, in order to improve scratch resistance of films and wettability to plastic substrates, it is often necessary to mix some polymer bonding agent with hydrophobic groups with the PEDOT/PSS system, which in turn has a very negative effect on the hydrophilicity. In addition, it has also been found that residual moisture in PEDOT/PSS films not only degrades the performance of certain electronic components, but also shortens the useful life of the device. Therefore, the development of an organic solvent dispersed PEDOT system is of great importance to the industries of organic electronic devices, novel light emitting devices, displays and the like. PEDOT organic dispersions there are also some studies reported that, while the PEDOT dispersions were prepared in different organic solvents (ethanol, butanol and acetonitrile) by Bashir et al, they have low measured electronic conductivity, non-uniform size of PEDOT particles, easy agglomeration and poor film-forming properties (Iran Polym J (2013)22: 599-611). Cloutet et al uses ferric dodecylbenzene sulfonate as an oxidant and a stabilizer, and uses functionalized polyisoprene as a co-stabilizer, and synthesizes PEDOT dispersivity in different organic solvents (cyclohexane, toluene, etc.), although the particle size is improved, the electronic conductivity and film forming property of the synthesized PEDOT are required to be further improved, and the preparation process of the functionalized polyisoprene is complex, has high requirements on equipment and environment, and affects the practical application thereof (Langmuir 2014,30, 12474-12482). In a patent (US 20020077450A1), polythiophene conductors are prepared by a phase transfer catalyst (crown ether, quaternary ammonium salt and the like) in an anhydrous or low-water-content solvent, but the electronic conductivity and the film forming property are general, and the stability of the solution is poor.

Generally, methods for synthesizing a conductive polymer PEDOT mainly include a chemical oxidation method and an electrochemical method. The preparation of the conductive polymer PEDOT by the electrochemical method is generally applied to the growth of thin films, self-supporting films and the like on conductive substrates, and the electrochemical method requires the conductive substrates to synthesize the conductive polymer PEDOT, so that the practical application of the conductive polymer PEDOT is limited.

The invention content is as follows:

the invention aims to overcome the defects of the prior art and provide a conductive polymer PEDOT organic dispersion system and a preparation method thereof, wherein the dispersion system obtained by selecting a proper organic solvent system and a proper surfactant has good film-forming property and chemical stability, can be dispersed in an organic system in a colloid form for a long time, does not generate sedimentation and stably exists, has excellent electronic conductivity, has very important practical significance for solving the practical application of the conductive polymer of a non-aqueous dispersion system, can promote the further development of the high-conductivity PEDOT organic dispersion system, and has important significance for promoting the development of strategic emerging industries of organic electronic equipment, novel light emitting and display industries, even chargeable and dischargeable polymer batteries, Organic Light Emitting Diodes (OLEDs) and the like.

The invention is realized by the following technical scheme:

the conductive polymer PEDOT organic dispersion system comprises an organic solvent with strong polarity and high dielectric constant, PEDOT, and further comprises an organic strong acid or salt conductive dopant and a surfactant, wherein the content of the PEDOT is 0.1-0.5 wt.%, the content of the organic strong acid or salt conductive dopant is 0.1-5.0 wt.%, and the content of the surfactant is 0.1-4.6 wt.%; the organic solvent with strong polarity and high dielectric constant is selected from one or more than two of propylene carbonate, ethylene carbonate, ethanol, butanol, acetonitrile, isopropanol and tetrahydrofuran;

the preparation method of the PEDOT organic dispersion system comprises the following steps:

carrying out oxidative polymerization on a conductive high-molecular monomer 3, 4-Ethylenedioxythiophene (EDOT) and an oxidant in a strong-polarity and high-dielectric-constant organic solvent for 6-48 h at the temperature of 25-80 ℃; adding an organic strong acid or salt conductive dopant and a surfactant into the reaction system; the organic strong acid or salt conductive dopant is selected from one or two of p-toluenesulfonic acid, trifluoromethanesulfonic acid, methanesulfonic acid, dodecylbenzenesulfonic acid, polystyrene sulfonic acid and tetraethylammonium perchlorate; the oxidant is selected from one or more than two of ferric sulfate, ferric trichloride and ferric p-toluenesulfonate; the content of the oxidant in the reaction system is 0.1 wt.% to 1 wt.%.

The surfactant is one or more selected from polyvinylpyrrolidone, polyvinylidene fluoride, polyethylene glycol, sodium dodecyl benzene sulfonate, sodium dodecyl sulfate and cetyl trimethyl ammonium bromide.

The amount of the surfactant is 0.1-5% of the total mass of the organic solvent.

Preferably, the organic solvent is a mixed solvent of propylene carbonate and ethanol in a volume ratio of 1:1 or 1: 3.

Preferably, the oxidizing agent is selected from ferric sulfate or ferric p-toluenesulfonate.

Preferably, the conductive dopant is selected from p-toluenesulfonic acid, trifluoromethanesulfonic acid or methanesulfonic acid.

Preferably, the polymerization temperature is 80 ℃ and the reaction time is 24 h.

Preferably, the surfactant is selected from polyvinylpyrrolidone, has a molecular weight of 5,8000, and is added in an amount of 0.5% of the total mass of the organic solvent.

When the organic strong acid conductive dopant is selected from p-toluenesulfonic acid, particularly p-toluenesulfonic acid monohydrate (abbreviated as p-TSA), and the oxidant is selected from ferric sulfate, the chemical formula of PEDOT synthesis is as follows:

the surfactant is added into the reaction system as a stabilizer and a dispersing agent, and the film-forming property of the PEDOT organic dispersion system is improved at the same time, and is shown as the following formula:

particularly, a certain amount of strong polar organic solvent or organic compound lithium salt is added into the prepared PEDOT organic dispersion liquid system to serve as a post-doping agent, so that the conductivity and the film-forming property of the organic dispersion system are further improved, and the addition amount of the PEDOT organic dispersion liquid system is 0.1-5.0% of the total mass of the organic solvent.

In particular, the strongly polar organic solvent or the organic compound lithium salt rear dopant is selected from one or more of dimethyl sulfoxide (DMSO), lithium bistrifluoromethanesulfonylimide (LiTFSI), N-methylpyrrolidone (NMP), Dimethylformamide (DMF), ethylene glycol, sugar alcohol, 2-methylimidazole, preferably from dimethyl sulfoxide (DMSO), lithium bistrifluoromethanesulfonylimide (LiTFSI).

The invention has the following beneficial effects:

1) according to the invention, by selecting a proper organic solvent system, a proper surfactant and adopting a post-doping method, PEDOT particles can be wrapped in the surfactant to avoid adverse effects of moisture and humidity on the surfactant, and the stability and film-forming property of a dispersion system are improved. Organic solvents are generally more volatile than water, which is beneficial for better film formation. In addition, the electronic conductivity of the PEDOT conductive particles can be further improved by a post-doping method, and practical application and research of the PEDOT conductive particles are promoted.

2) The preparation of the PEDOT organic dispersion liquid with high conductivity, high stability and excellent film forming property by the chemical oxidation method has very important practical significance for solving the practical application of the conductive polymer of the non-aqueous dispersion system, can promote the high-conductivity PEDOT organic dispersion system to be further applied, and has important significance for promoting the development of the PEDOT organic dispersion liquid in the strategic emerging industries of organic electronic equipment, novel light emitting and display industries, even chargeable and dischargeable polymer batteries, Organic Light Emitting Diodes (OLED) and the like.

In conclusion, the dispersion system obtained by selecting a proper organic solvent system and a proper surfactant has good film forming property and chemical stability, can be dispersed in an organic system in a colloid form for a long time, does not generate sedimentation and stably exists, has excellent electronic conductivity, has very important practical significance for solving the practical application of the conductive polymer of a non-aqueous dispersion system, can promote the further development of the high-conductivity PEDOT organic dispersion system, and has important significance for promoting the development of the high-conductivity PEDOT organic dispersion system in the strategic industries of organic electronic equipment, novel light emitting and display industries, even chargeable and dischargeable polymer batteries, Organic Light Emitting Diodes (OLEDs) and the like, and has wide market prospect.

Description of the drawings:

FIG. 1 is a comparison of the film formation on glass slides of PEDOT organic dispersions of examples 1-3 of the invention prepared with PVP of different molecular weights and of dispersions prepared in comparative example 1.

Wherein, (a) refers to comparative example 1; (b) example 1; (c) refer to example 2; (d) referred to in example 3.

Figure 2 is a comparison of the film formation and particle size of PEDOT prepared using PVP of molecular weight 58,000 in example 2 of the present invention with that of PEDOT prepared in comparative example 1.

Wherein (a) and (b) refer to the film forming properties and particle size of PEDOT prepared in comparative example 1; (c) and (d) refers to the film forming and particle size of the PEDOT prepared in example 2.

Fig. 3 is a comparison of the film formation on glass slides of PEDOT organic dispersions prepared according to examples 4-5 of the invention with different amounts of PVP (Mw 58,000) and the dispersions prepared according to comparative example 1.

Wherein (a) refers to example 4-film forming properties for preparing PEDOT; (b) refers to the film-forming property of PEDOT prepared in example 2; (c) referring to the film forming properties of PEDOT prepared in example 5.

FIG. 4 is a scanning electron micrograph comparison of the film formation on copper foil of PEDOT organic dispersions treated with the post dopant LiTFSI of inventive example 24 and a comparative dispersion.

Wherein (a) refers to the film-forming property of the unused dopant to PEDOT organic dispersibility; (b) refers to the organic dispersive film forming property of PEDOT prepared by using the post-doping agent LiTFSI in example 24.

The specific implementation mode is as follows:

the following is a further description of the invention and is not intended to be limiting.

The invention provides a preparation method of the PEDOT organic dispersion system with high conductivity, high stability and excellent film forming property, and compares the particle size, the film forming property and the electronic conductivity with the PEDOT dispersion system without adopting a surfactant and a post-doping agent, the commercial organic PEDOT dispersion liquid and the like.

Polyvinylpyrrolidone (Mw. 8000,58000 and 1300000) used in the specific examples of the invention was purchased from alatin, and comparative commercial organic PEDOT dispersant was purchased from Sigma-Aldrich (0.5 wt.% propylene carbonate dispersion with p-toluenesulfonic acid as dopant, tetra methyl acrylate end-capped).

Example 1: preparation of PEDOT organic dispersion:

weighing 0.35g of Fe under the protection of argon inert atmosphere₂(SO₄)₃And 1g of p-toluenesulfonic acid monohydrate (p-TSA, as a dopant) dissolved in a mixed organic solvent system of Propylene Carbonate (PC) and ethanol, wherein the volume ratio of PC to ethanol is 1: 3; then, 0.2g of polyvinylpyrrolidone (PVP, Mw 8,000) as a surfactant was added and sufficiently stirred to be dissolved; and finally, adding 0.1g of EDOT monomer, and stirring and reacting at 80 ℃ for 24 hours to obtain PEDOT organic dispersion liquid, wherein the PEDOT organic dispersion liquid comprises an organic solvent with strong polarity and high dielectric constant, PEDOT, an organic strong acid or salt conductive dopant and a surfactant, the PEDOT content is 0.24 wt.%, the organic strong acid or salt conductive dopant content is 2.41 wt.%, and the surfactant content is 0.5 wt.% of the total mass of the organic solvent. The prepared PEDOT organic dispersion was coated on a glass slide glass to measure its film-forming property, and its electronic conductivity was measured using an RTS-9 four-probe tester, and its film-forming property and electronic conductivity were as shown in fig. 1 and table 1, respectively.

Comparative example 1:

reference example 1, except that polyvinylpyrrolidone (PVP) was not added as a surfactant. The prepared PEDOT organic dispersion was coated on a glass slide glass to measure its film-forming property, and its electronic conductivity was measured using an RTS-9 four-probe tester, and its film-forming property and electronic conductivity were as shown in fig. 1 and table 1, respectively. The particle size is shown in FIG. 2.

Example 2:

reference example 1, except that: polyvinylpyrrolidone, with a molecular weight of 58,000, was added. The prepared PEDOT organic dispersion was coated on a glass slide glass to measure its film-forming property, and its electronic conductivity was measured using an RTS-9 four-probe tester, and its film-forming property and electronic conductivity were as shown in fig. 1 and table 1, respectively. The particle size is shown in FIG. 2.

Example 3:

reference example 1, except that: polyvinylpyrrolidone was added, having a molecular weight of 1300,000. The prepared PEDOT organic dispersion was coated on a glass slide glass to measure its film-forming property, and its electronic conductivity was measured using an RTS-9 four-probe tester, and its film-forming property and electronic conductivity were as shown in fig. 1 and table 1, respectively.

TABLE 1 preparation of organic dispersions of PEDOT with different molecular weights of PVP as stabilizer

As can be seen from FIG. 1 and Table 1, polyvinylpyrrolidone (PVP, M) was used_w8000,58000 and 1300000) as a stabilizer, the film forming property of the PEDOT organic dispersion (fig. 1(b-d)) is greatly improved, the connectivity between particles is better, a conductive polymer film can be spread on the glass sheet, no obvious film shrinkage and particle fracture exist, and the film forming property on the glass sheet is better than that of the PEDOT system without adding PVP (fig. 1 (a)). In addition, it still did not settle over a long period of storage for 30 days, and its electronic conductivity was higher than that of the PEDOT organic dispersion prepared without PVP as a surfactant. PEDOT particles prepared with PVP having a molecular weight of 5,8000 as surfactant, which possessed the highest electronic conductivity of 1.67*10^-2s cm^-1Compared to PEDOT system without PVP (5.2 x 10)^-4s cm^-1) And commercial organic PEDOT dispersions (4.7 x 10)^-4s cm^-1) Is high.

As can be seen from FIG. 2, the particle size of PEDOT prepared with PVP is between 200 and 350nm, which is smaller than that of PEDOT prepared without PVP in comparative example 1 (300nm-1 μm), and the dispersion has good film-forming property.

Example 4:

reference example 1, except that: polyvinylpyrrolidone having a molecular weight of 58,000 was added in an amount of 0.04 g. The film forming property and the electronic conductivity are shown in fig. 3 and table 2, respectively.

Example 5:

reference example 1, except that: polyvinylpyrrolidone having a molecular weight of 58,000 was added in an amount of 2 g. The film forming property and the electronic conductivity are shown in fig. 3 and table 2, respectively.

Table 2 shows different amounts of PVP (M) added_w58,000) stabilizer to prepare organic dispersions of PEDOT

FIG. 3 shows that different amounts of PVP (M) were used in examples 4-5_w58,000) prepared PEDOT organic dispersions and comparative example 1 the dispersions were compared for film formation on glass slides and table 2 shows their corresponding electronic conductivity measurements. As can be seen from FIG. 3 and Table 2, different amounts of polyvinylpyrrolidone (PVP, M) were used_w58000) as a surfactant, the film formation of the PEDOT organic dispersion was greatly improved and no sedimentation occurred after a long storage time of 30 days, while the PEDOT, which was not prepared with PVP, showed a small amount of particle precipitates. Furthermore, the electronic conductivity of the obtained organic dispersion of PEDOT (except example 5) was higher than that of the organic dispersion of PEDOT prepared without PVP as a surfactant. PEDOT particles prepared with 0.2g PVP of molecular weight 5,8000 as stabiliser, which possessed the highest electronic conductivity 1.67 x 10^-2s cm^-1Comparison with the system without PVP (5.2 x 10)^-4s cm^-1) Is high.

Example 6:

reference example 1, except that: the conductive dopant added is trifluoromethanesulfonic acid (CF)₃SO₃H) 0.78g, polyvinylpyrrolidone having a molecular weight of 58,000 was added. The electronic conductivity is shown in table 3.

Example 7:

reference example 1, except that: the conductive dopant added is methanesulfonic acid (CH)₃SO₃H) 0.50g of polyvinylpyrrolidone having a molecular weight of 58,000 was added. The electronic conductivity is shown in table 3.

Example 8:

reference example 1, except that: the conductive dopant is dodecylbenzene sulfonic acid (C)₁₈H₃₀SO₃) 1.71g of polyvinylpyrrolidone having a molecular weight of 58,000 was added. The electronic conductivity is shown in table 3.

Example 9:

reference example 1, except that: the conductive dopant added was polystyrene sulfonic acid (PSSH) added in an amount of 0.96g, and polyvinylpyrrolidone added in an amount of molecular weight of 58,000. The electronic conductivity is shown in table 3.

TABLE 3 preparation of organic PEDOT dispersions with the addition of different conductive dopants

Table 3 is a comparative table of the electronic conductivity of organic PEDOT dispersions prepared with different conductivity dopants for examples 6-9. As can be seen from Table 3, organic dispersions of PEDOT prepared using trifluoromethanesulfonic acid, methanesulfonic acid, dodecylbenzenesulfonic acid and polyvinylbenzenesulfonic acid as dopantsThe electronic conductivity of the material is 6.67 x 10^-2scm^-1、4.17*10^-3s cm^-1、5.69*10^- ²s cm^-1And 1.54 x 10^-3s cm^-1All of which have higher electronic conductivity than commercial organic PEDOT dispersions (4.7 x 10)^-4s cm^-1). The result shows that different organic strong acids are used as conductive dopants to adjust the acidity of the reaction system and change the conjugation length and doping degree of a PEDOT molecular chain, so that the electronic conductivity of the PEDOT organic dispersion system can be further improved, and the practical application of the PEDOT organic dispersion liquid can be widened.

Example 10:

reference example 1, except that: the added surfactant was polyethylene glycol, and polyvinylpyrrolidone having a molecular weight of 58,000 was added. The electronic conductivity is shown in table 4.

Example 11:

reference example 1, except that: the surfactant added was polyvinylidene fluoride, polyvinylpyrrolidone added, and its molecular weight was 58,000. The electronic conductivity is shown in table 4.

TABLE 4 organic PEDOT dispersions with different surfactant additions

Table 4 is a comparative table of electronic conductivity tests of organic PEDOT dispersions prepared with different surfactants on glass slides for examples 10-11. As can be seen from table 4, the electronic conductivity of the PEDOT organic dispersions prepared using polyethylene glycol or polyvinylidene fluoride as a surfactant was higher than that of the PEDOT organic dispersions prepared without using a surfactant as a stabilizer. PEDOT particles prepared using polyethylene glycol or polyvinylidene fluoride as stabilizer, having an electronic conductivity of 1.52 x 10, respectively^-3s cm^-1And 1.21*10^-3scm^-1In comparison with PEDOT systems without surfactant (comparative examples 1, 5.2 x 10)^-4s cm^-1) And commercial organic PEDOT dispersions (4.7 x 10)^-4s cm^-1) Is high.

Example 12:

reference example 1, except that: the solvent used was Propylene Carbonate (PC), polyvinylpyrrolidone added, having a molecular weight of 58,000. The electronic conductivity is shown in table 5.

Example 13:

reference example 1, except that: the solvent is a mixed organic solvent of Propylene Carbonate (PC) and ethanol, wherein the volume ratio of PC to ethanol is 1:1, and the added polyvinylpyrrolidone has a molecular weight of 58,000. The electronic conductivity is shown in table 5.

Example 14:

reference example 1, except that: the solvent used was Ethanol (Ethanol), polyvinylpyrrolidone added, and having a molecular weight of 58,000. The electronic conductivity is shown in table 5.

TABLE 5 preparation of organic PEDOT dispersions Using organic solvent systems in different volume ratios

Table 5 shows the electronic conductivity of organic PEDOT dispersions prepared in examples 2, 12 to 14 using organic solvent mixed systems of different volume ratios. As can be seen from Table 5, the PEDOT organic dispersion prepared using a mixed organic solvent of Propylene Carbonate (PC) and ethanol, wherein the volume ratio of PC to ethanol is 1:3, had the highest electronic conductivity of 1.67 x 10^-2s cm^-1Comparison with the system without the surfactant PVP (5.2 x 10)^-4s cm^-1) And other PC to ethanol volume ratios, and does not settle over a long storage period of 30 days.

Example 15:

reference example 1, except that: the solvent is a mixed organic solvent of Ethylene Carbonate (EC) and ethanol, wherein the volume ratio of EC to ethanol is 1: 3. Polyvinylpyrrolidone, with a molecular weight of 58,000, was added. The electronic conductivity is shown in Table 6.

Example 16:

reference example 1, except that: the solvent is a mixed organic solvent of Tetrahydrofuran (THF) and ethanol, wherein the volume ratio of THF to ethanol is 1: 3. Polyvinylpyrrolidone, with a molecular weight of 58,000, was added. The electronic conductivity is shown in Table 6.

TABLE 6 preparation of organic PEDOT dispersions Using different organic solvent mixture systems

Table 6 shows the electronic conductivity of organic PEDOT dispersions prepared in examples 15-16 using different organic solvent mixture systems. As can be seen from Table 6, the electron conductivity of the organic dispersions of PEDOT prepared using the mixed organic solvent of Ethylene Carbonate (EC) and ethanol, and Tetrahydrofuran (THF) and ethanol was 6.82 x 10^-3s cm^-1And 3.57 x 10^-3s cm^-1Comparison with the system without the surfactant PVP (5.2 x 10)^-4s cm^-1) And other PC-ethanol, and does not settle over a long storage period of 30 days.

Example 17:

reference example 1, except that: the oxidant used is FeCl₃Polyvinylpyrrolidone, with a molecular weight of 58,000, was added. The electronic conductivity is shown in Table 7.

TABLE 7 preparation of organic PEDOT dispersions using different oxidizing agents

Table 7 shows the electronic conductivity comparison of organic PEDOT dispersions prepared in example 17 using different oxidizing agents. As can be seen from Table 7, using Fe₂(SO₄)₃Organic dispersions of PEDOT prepared as oxidizing agent, possessing a high electronic conductivity of 1.67 x 10^-2s cm^-1Using FeCl₃System of oxidizing agents (1.5 x 10)^-4s cm^-1) High and no sedimentation occurred after a long storage time of 30 days.

Example 18:

reference example 1, except that: the polymerization temperature used was 25 ℃ and polyvinylpyrrolidone having a molecular weight of 58,000 was added. The electronic conductivity is shown in Table 8.

Example 19:

reference example 1, except that: the polymerization temperature used was 50 ℃ and polyvinylpyrrolidone having a molecular weight of 58,000 was added. The electronic conductivity is shown in Table 8.

TABLE 8 preparation of PEDOT organic dispersions using different polymerization temperatures

Table 8 shows a comparison of the electronic conductivity of organic PEDOT dispersions prepared in examples 18-19 using different oxidizing agents. As can be seen from Table 8, the organic PEDOT dispersions prepared at 80 ℃ polymerization temperature possess a relatively high electronic conductivity of 1.67 x 10^-2s cm^-1Higher than systems using other polymerization temperatures (25 ℃ and 50 ℃) and over a long period of 30 daysNo sedimentation occurred under storage.

Example 20:

reference example 1, except that: polyvinylpyrrolidone, with a molecular weight of 58,000, was added. The polymerization time used was 6 h; the electronic conductivity is shown in Table 9.

Example 21:

reference example 1, except that: polyvinylpyrrolidone, with a molecular weight of 58,000, was added. The polymerization time used was 12 h; the electronic conductivity is shown in Table 9.

Example 22:

reference example 1, except that: polyvinylpyrrolidone, with a molecular weight of 58,000, was added. The polymerization time used was 48 h; the electronic conductivity is shown in Table 9.

TABLE 9 preparation of organic PEDOT dispersions for different polymerization times

Table 9 shows a comparison of the electronic conductivity of organic PEDOT dispersions prepared for examples 20-22 using different polymerization times. As can be seen from Table 9, the organic PEDOT dispersions prepared with a polymerization time of 24h had a relatively high electronic conductivity of 1.67 x 10^-2s cm^-1Higher than systems using other polymerization times (6h,12h and 48h) and no sedimentation occurred over a long storage period of 30 days.

Example 23:

reference example 1, except that: to the prepared PEDOT dispersion, dimethyl sulfoxide (DMSO) was added as a post dopant, and the electronic conductivity thereof is shown in table 10.

Example 24:

reference example 1, except that: to the prepared PEDOT dispersion, lithium bistrifluoromethanesulfonylimide (LiTFSI) was added as a post dopant, the electronic conductivity thereof is shown in table 10, and a scanning electron micrograph of the film-forming property thereof on a copper foil can be seen in fig. 4.

Example 25:

reference example 1, except that: to the prepared PEDOT dispersion, N-methylpyrrolidone (NMP) was added as a post dopant, and the electronic conductivity thereof is shown in table 10.

Example 26:

reference example 1, except that: to the prepared PEDOT dispersion, methyl formamide (DMF) was added as a post-dopant, and the electronic conductivity thereof is shown in table 10.

TABLE 10 preparation of organic PEDOT dispersions with different post-dopants

Table 10 compares the electronic conductivity of organic PEDOT dispersions treated with different post-dopants for examples 23-26. FIG. 4 is a comparative scanning electron microscope film formation on copper foil of PEDOT organic dispersions treated with post-dopant LiTFSI according to example 24 of the present invention and comparative dispersions. As can be seen from table 10, the electronic conductivity of the PEDOT organic dispersions prepared with different post dopants (DMSO, LiTFSI, NMP, and DMF) was improved to some extent compared to that before doping, and the electronic conductivity of the film was improved in stability, film-forming property was good, and no sedimentation occurred after long-term storage for 30 days. As can be seen from fig. 4, when the post-dopant LiTFSI is used to treat the PEDOT organic dispersion, the film-forming property of the PEDOT organic dispersion on the copper foil is greatly improved, and the dispersibility and uniformity of the particles are greatly improved under the observation of a scanning electron microscope.

Finally, it should be noted that the above embodiments are only used for illustrating the technical solutions of the present invention and not for limiting the protection scope of the present invention, and although the present invention is described in detail with reference to the preferred embodiments, it should be understood by those skilled in the art that modifications or equivalent substitutions can be made on the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention.

Claims

1. The conductive polymer PEDOT organic dispersion system is characterized by comprising an organic solvent with strong polarity and high dielectric constant, PEDOT, an organic strong acid or salt conductive dopant and a surfactant, wherein the content of the PEDOT is 0.1-0.5 wt.%, the content of the organic strong acid or salt conductive dopant is 0.1-5.0 wt.%, and the content of the surfactant is 0.1-4.6 wt.%; the organic solvent with strong polarity and high dielectric constant is selected from one or more than two of propylene carbonate, ethylene carbonate, ethanol, butanol, acetonitrile, isopropanol and tetrahydrofuran; the surfactant is selected from one or more of polyvinylpyrrolidone, polyvinylidene fluoride, polyethylene glycol, sodium dodecyl benzene sulfonate, sodium dodecyl sulfate and hexadecyl trimethyl ammonium bromide; the preparation method of the PEDOT organic dispersion system comprises the following steps: carrying out oxidative polymerization on a conductive high-molecular monomer 3, 4-ethylenedioxythiophene and an oxidant in a strong-polarity and high-dielectric-constant organic solvent for 6-48 h at the temperature of 25-80 ℃; adding an organic strong acid or salt conductive dopant and a surfactant into the reaction system; the organic strong acid or salt conductive dopant is selected from one or two of p-toluenesulfonic acid, trifluoromethanesulfonic acid, methanesulfonic acid, dodecylbenzenesulfonic acid, polystyrene sulfonic acid and tetraethylammonium perchlorate; the oxidant is selected from one or more than two of ferric sulfate, ferric trichloride and ferric p-toluenesulfonate, and the content of the oxidant in the reaction system is 0.1-1 wt.%.

2. The organic dispersion of PEDOT according to claim 1, wherein the amount of surfactant is 0.1% to 5% by weight of the total organic solvent.

3. The PEDOT organic dispersion system according to claim 1 or 2, wherein the organic solvent is a mixed solvent of propylene carbonate and ethanol in a volume ratio of 1:1 or 1: 3.

4. Organic dispersion of PEDOT according to claim 1 or 2, characterized in that the polymerization temperature is 80 ℃ and the reaction time is 24 h.

5. PEDOT organic dispersion according to claim 1 or 2, characterized in that the surfactant is selected from polyvinylpyrrolidone with molecular weight 5,8000, added in an amount of 0.5% of the total mass of organic solvent.

6. PEDOT organic dispersion according to claim 1 or 2, characterised in that it is added a strongly polar organic solvent or a lithium salt of an organic compound as a back dopant.

7. The PEDOT organic dispersion system according to claim 6, wherein the strongly polar organic solvent or lithium salt of an organic compound is selected from one or more of dimethyl sulfoxide, lithium bistrifluoromethanesulfonylimide, N-methylpyrrolidone, dimethylformamide, ethylene glycol, sugar alcohols, 2-methylimidazole.