Method for obtaining water-soluble n-type conductive polymers

Abstract

The present invention provides a method for producing a water-soluble n-type conductive polymer, comprising the steps of: a) adding a monomer to a solvent system comprising water in the presence of a catalyst to prepare a reaction solution; b) polymerizing the monomer in the reaction solution to obtain an n-type conductive polymer solution; c) post-treating the n-type conductive polymer solution to obtain a water-soluble n-type conductive polymer; The present invention relates to a method comprising:

Description

[Technical Field]

[0001] The present invention relates to a method for producing a water-soluble n-type conductive polymer, a water-soluble n-type conductive polymer obtained by such a method, and a water-based ink comprising the water-soluble n-type conductive polymer obtained by such a method. [Background technology]

[0002] Water-based conductive polymer inks have a wide range of industrial applications, including antistatic coatings, polymer capacitors, organic solar cells, displays (LCD / OLED), and printed electronics. PEDOT:PSS is a commercially available p-type (hole-transporting) water-based conductive polymer ink with a pure electrical conductivity of 1 S cm. -1 and exceeds 4000 S cm by secondary doping or post-treatment. -1 However, when considering complementary components for semiconductor devices and circuits, water-based n-type (electron transporting) conducting polymers become important.

[0003] The BBL:PEI ethanol-based inks reported in WO 2022 / 106017 and WO 2022 / 106018 are a first step toward environmentally friendly solvent-based inks. However, there are several issues that partially limit their application. First, ethanol has strict requirements regarding fire prevention during production, transportation, storage, and use. Furthermore, the inks disclosed in the above applications are primarily limited to deposition methods such as spray casting, spin casting, and the like due to their large particle size. As can be seen from the above references, the maximum electrical conductivity of BBL:PEI inks is 10 S cm. -1 less than 1000 .mu.m and is not suitable for devices that are sensitive to sheet resistance.

[0004] Recently, Fei Huang et al. -1We report a solution-processed n-type conductive polymer, poly(benzodifurandione) (PBFDO), with electrical conductivity exceeding 100 kJ / cm (Nature, 2022, s41586-022-05295-8). PBFDO is polymerized and processed in dimethylformamide (DMF) or dimethyl sulfoxide (DMSO), solvents that are difficult to print in industrial environments.

[0005] The development of water-based n-type CP inks with high conductivity, processability, and stability comparable to PEDOT:PSS remains a challenging scientific and industrial endeavor with far-reaching implications for low-cost printed organic electronics. Summary of the Invention

[0006] In view of the above, the present invention aims to solve the problems of the prior art. To this end, the present invention provides a method for producing a water-soluble n-type conductive polymer, comprising the steps of: a) adding a monomer to a solvent system comprising water in the presence of a catalyst to prepare a reaction solution; b) polymerizing the monomer in the reaction solution to obtain an n-type conductive polymer solution; c) post-treating the n-type conductive polymer solution to obtain a water-soluble n-type conductive polymer; The present invention relates to a method comprising:

[0007] The monomer has a centrosymmetric benzene ring as the backbone, an active hydrogen, and at least one electron-withdrawing group at the benzylic position, such as a carbonyl, carboxyl, amide, alkoxyacyl, or the like. [ka]

[0008] Furthermore, the monomer may be in the form of a heterocyclic moiety having a centrosymmetric benzene ring fused with at least one, preferably at least two, rings, preferably a five-membered ring. The monomer further comprises an active hydrogen and at least one electron-withdrawing group at the benzylic position. In particular, the monomer may be 3,7-dihydrobenzo[1,2-b:4,5-b']difuran-2,6-dione (HBFDO), 5,7-dihydropyrrolo[2,3-f]indole-2,6(1H,3H)-dione, or 3,7-dihydrobenzo[1,2-b:4,5-b']dithiophene-2,6-dione. [ka]

[0009] In particular, the monomer is 3,7-dihydrobenzo[1,2-b:4,5-b']difuran-2,6-dione (HBFDO). In such an embodiment, the n-type conductive polymer is polybenzodifurandione (PBFDO). A general overview of the method of the present invention is summarized as follows: [ka] Here, TMQ or AQ is a catalyst as described below. [ka]

[0010] According to a first embodiment, the solvent system consists of water. In other words, the solvent system comprises substantially only water, for example at least 99% by volume (vol%). Such an embodiment offers the advantage of a cost-effective and environmentally friendly production method.

[0011] In embodiments where the solvent system consists of water, the method further comprises: a') adding a base to the reaction solution Further includes:

[0012] Step a') can be carried out during or immediately after step a), in other words, the base can be added to the reaction solution simultaneously with the monomer and the catalyst, or can be added immediately after the addition of the monomer and the catalyst.

[0013] Furthermore, the method comprises: a'') adding a surfactant to the reaction solution It may further include:

[0014] Step a') can be carried out during or immediately after step a). In other words, the surfactant can be added to the reaction solution simultaneously with the monomer and the catalyst, or immediately after the addition of the monomer and the catalyst. Furthermore, step a'') can be carried out immediately before step a'), immediately after step a'), or simultaneously with step a').

[0015] As will be appreciated from the above, the surfactant is not essential to the method according to the first embodiment, but it must be added if the polymer is intended to be used for spin casting.

[0016] According to a first embodiment, the catalyst may be an alkyl- and carboxyl-substituted benzoquinone (AQ). Such a catalyst may be 3-(2,4,5-trimethyl-3,6-dioxocyclohexa-1,4-dien-1-yl)propanoic acid (AMMMQ, R 0 =R 1 =R 3 =Me), 3,3'-(4,5-dimethyl-3,6-dioxocyclohexa-1,4-diene-1,2-diyl)dipropionic acid (AAMMQ, R = R = Me, R = -CHR RCOOH, R, R = H or Me), 3,3'-(2,5-dimethyl-3,6-dioxocyclohexa-1,4-diene-1,4-diyl)dipropionic acid (AMAMQ, R = R = Me, R = -CHR RCOOH, R, R = H or Me), and combinations thereof.

[0017] As shown in the scheme below, the catalyst can be easily isolated, recovered, and recycled for further polymerizing PBFDO. [ka]

[0018] AQs can be synthesized by a Michael addition reaction followed by oxidation with N-bromosuccinimide (NBS), as described in detail below. AQs are highly crystalline, water-insoluble organic acids. However, when neutralized with a strong base, AQs become highly water-soluble [AQs]. - If the solvent system consists of water, [AQs] - In the presence of surfactants, [AQs] can catalyze the polymerization of the water-insoluble HBFDO monomer to the water-soluble PBFDO. - The main advantages of PBFDO inks are that they can be converted into water-insoluble AHQs and AQs and separated from the ink by simple suction filtration. The mixture of AHQs and AQs can be converted into pure AQs by mild oxidation. Therefore, AQs can be easily recycled, offering the advantages of being cost-effective and environmentally friendly.

[0019] According to a first embodiment of the invention, the base is MOH and M is Li + , Na + , K. + , Me4N + , Bu4N + or a combination thereof.

[0020] The surfactant may be selected from polyethylene glycol (PEG), polyvinylpyrrolidone (PVP), polyvinyl alcohol (PVA), sodium polystyrene sulfonate (PSSNa), polystyrene sulfonic acid (PSSH), sodium dodecylbenzene sulfonate (DBSNa), polyquaternium-4 (PQ-4), polyquaternium-10 (PQ-10), polydiallyldimethylammonium chloride (PDADMAC), polydiallyldiethylammonium chloride (PDADEAC), TWEEN® 20, TWEEN® 80, κ-carrageenan, PEG-PPG-PEG, polyoxyethylene (10) tridecyl ether, Triton™ X-100, or a combination thereof. [ka]

[0021] PBFDO is soluble in DMSO and obtained using the polymerization method reported by Huang et al., but it precipitates when water is added to the DMSO solution. In other words, PBFDO polymerized in DMSO cannot be dissolved in water, even in the presence of surfactants such as polyethylene glycol (PEG). Surprisingly, we found that prepolymerization in water in the presence of AQ and a base promoted the formation of water-soluble PBFDO micelles, which were further stabilized by the addition of a surfactant.

[0022] In a second embodiment of the present invention, the solvent system may further comprise a polar aprotic solvent. In such an embodiment, the method comprises: d) performing a solvent exchange to remove the polar aprotic solvent Further includes:

[0023] The polar aprotic solvent may be dimethyl sulfoxide (DMSO), dimethylformamide (DMF), dimethylacetamide (DMA), or a combination thereof. The ratio of water to the polar aprotic solvent is 5:95 to 95:5, preferably 40:60 to 60:40.

[0024] In a second embodiment of the present invention (i.e., the solvent system further comprises a polar aprotic solvent), the catalyst may be a quinone oxidant selected from tetramethylbenzoquinone (TMQ), alkyl- and carboxyl-substituted benzoquinones (AQ), or combinations thereof.

[0025] The present inventors have surprisingly found that carrying out the polymerization reaction in a solvent system comprising water and a polar aprotic solvent promotes the formation of water-soluble PBFDO micelles, which can be further stabilized by adding a surfactant, for example, as disclosed above. However, in the second embodiment of the present invention, a surfactant is not required. If a surfactant is used, it can be added during step d) above.

[0026] Even after the polar aprotic solvent is completely removed, the PBFDO micelles can still dissolve in water.

[0027] The polymerization step (i.e., step b) can proceed at temperatures between 20°C and 150°C. In particular, [AQ]- showed much stronger catalytic activity than TMQ. In the second embodiment of the present invention (i.e., the solvent system further comprises a polar aprotic solvent), [AQ]- can catalyze the polymerization of HBFDO to PBFDO at room temperature, which is a great advantage in terms of cost efficiency.

[0028] As mentioned above, the method of the present invention comprises: c') removing the catalyst by filtration and oxidation to recycle the catalyst. It may further include:

[0029] The method of the present invention may also include additional steps, such as work-up and purification steps, which may be carried out in water.

[0030] The present invention further relates to a water-soluble n-type conductive polymer obtained by the above method. The polymer may be in the form of micelles with a diameter of less than 200 nm. The particle size can be easily verified by filtering the polymer solution through a 20 μm filter. After filtration, the solution is observed to remain colored, indicating that the polymer micelles have passed through the filter.

[0031] The present invention also relates to a water-based ink comprising the water-soluble n-type conductive polymer described above.

[0032] Therefore, the n-type conductive ink of the present invention can be spin-coated or drop-cast in air at room temperature to form a film with a thickness of 1 nm to 1 cm, more preferably 10 nm to 10 μm, which may exhibit an electrical conductivity of about 5 S / cm.

[0033] The present invention further relates to an organic optical device or an organic electronic device comprising the above n-type conductive composition.

[0034] As mentioned above, the n-type water-based conductive ink according to the present invention can be used in organic optical or electronic devices such as OECTs, thermoelectric devices, ternary logic inverters, OPVs, OLEDs, organic supercapacitors, batteries, fuel cells, sensors, and memories.

[0035] Embodiments of the present invention will now be described, by way of example, with reference to the accompanying drawings, in which: [Brief explanation of the drawings]

[0036] [Figure 1] 1A-1D illustrate steps of a method according to a first embodiment of the present invention. [Figure 2] 5A-5C illustrate steps of a method according to a second embodiment of the present invention. [Figure 3] FIG. 1 shows a PBFDO-water-based ink at a concentration of 1.5 mg / mL. [Figure 4]FIG. 1 shows a PBFDO-water-based ink at a concentration of 0.1 mg / mL. [Figure 5] FIG. 1 shows the apparent hydrodynamic diameter of PBFDO water-based inks polymerized from DMSO-water mixed solvents with different water contents. [Figure 6] FIG. 1 shows the apparent hydrodynamic diameter of PBFDO water-based inks polymerized from DMSO-water mixed solvents with different water contents. DETAILED DESCRIPTION OF THE INVENTION

[0037] As mentioned above, the present invention provides a method for producing a water-soluble n-type conductive polymer, comprising the steps of: a) adding monomers to a solvent system comprising polar water in the presence of a catalyst to prepare a reaction solution; b) polymerizing the monomer in the reaction solution to obtain an n-type conductive polymer solution; c) post-treating the n-type conductive polymer solution to obtain a water-soluble n-type conductive polymer; The present invention provides a method comprising:

[0038] According to a first embodiment shown in Figure 1, the solvent system consists of water. The solvent system may comprise substantially only water, for example at least 99% by volume (vol%) water, and such an embodiment provides the advantage of a cost-effective and environmentally friendly manufacturing process.

[0039] As can be seen in FIG. a') adding a base and a surfactant to the reaction solution Further includes:

[0040] Step a') can be carried out during or immediately after step a), in other words, the base and surfactant can be added to the reaction solution simultaneously with the monomer and the catalyst, or can be added immediately after the addition of the monomer and the catalyst.

[0041] According to a first embodiment, the catalyst may be an alkyl- and carboxyl-substituted benzoquinone (AQ). Such a catalyst may be 3-(2,4,5-trimethyl-3,6-dioxocyclohexa-1,4-dien-1-yl)propanoic acid (AMMMQ, R 0 =R 1 =R 3 =Me), 3,3'-(4,5-dimethyl-3,6-dioxocyclohexa-1,4-diene-1,2-diyl)dipropionic acid (AAMMQ, R = R = Me, R = -CHR RCOOH, R, R = H or Me), 3,3'-(2,5-dimethyl-3,6-dioxocyclohexa-1,4-diene-1,4-diyl)dipropionic acid (AMAMQ, R = R = Me, R = -CHR RCOOH, R, R = H or Me), and combinations thereof.

[0042] As shown in the scheme below, the catalyst can be easily isolated, recovered, and recycled for further polymerizing PBFDO. [ka]

[0043] According to a specific embodiment of the present invention, the catalyst can be synthesized as follows: Methanesulfonic acid (10 mL) was heated to 70°C in an oil bath, and 2,3,5-trimethylbenzene-1,4-diol (1 g, 6.57 mmol) and tert-butyl acrylate (1.09 mL, 7.42 mmol) were added with stirring. The reaction was continued at 70°C for 90 minutes, after which the mixture was diluted with 100 mL of water and extracted three times with ethyl acetate. The extract was washed with water, saturated sodium bicarbonate (NaHCO3), saturated sodium chloride (NaCl), and dried (sodium sulfate (Na2SO4)). The solvent was removed using a rotary evaporator. The residue was purified by silica gel chromatography to give the pure solid lactone 3MCQ (0.81 g, 60% yield). To 90 mL of 10% aqueous acetonitrile containing lactone 3MCQ (1.8 g, 8.73 mmol) was added dropwise 18 mL of acetonitrile containing NBS (1.63 g, 9.16 mmol). The reaction mixture was stirred at 25 °C for 1 h, and the solvent was removed by rotary evaporation. The residue was diluted with water and extracted several times with ether. The combined ether extracts were washed with water and brine and dried (using sodium sulfate (Na2SO4)). The solvent was removed, and the product was crystallized (acetone-hexane) to give 1.5 g of AMMMQ (80% yield). [ka]

[0044] Water-soluble PBFDO micelles were synthesized as follows. To a suspension of the catalyst AMMMQ (46.75 mg, 0.21 mmol) in 1.6 mL of water, NaOH (0.42 mL, 0.5 M) was added, and after 10 min of stirring, a bright yellow solution was obtained. Next, the surfactant PDADMAC (100 mg, 0.63 mmol) and the monomer HBFDO (40 mg, 0.21 mmol) were added to the reaction mixture, which was then stirred at 100 °C overnight. The catalyst was separated by filtration, and the filtrate PBFDO-water solution was transferred to a dialysis bag and dialyzed against deionized water for two days to remove oligomers, yielding a PBFDO-water ink. The PBFDO-water ink could be diluted or concentrated to 1–50 mg / mL by centrifugal dialysis for spin casting, drop casting, and other thin-film fabrication methods.

[0045] The catalyst was recycled as follows: To the separated AMMMQ / AMMMHQ (45 mg, 0.2 mmol, 95% recovery) in 5 mL of acetonitrile:water (1:1) was added FeCl3·6H2O (215 mg, 0.8 mmol) in 1 mL of aqueous solution. The reaction mixture was stirred at room temperature for 10 min, diluted with water, and extracted several times with ether. The combined ether extracts were washed with water, brine, and dried (Na2SO4). Removal of the solvent and crystallization (acetone-hexane) afforded 41 mg (92% yield) of catalyst AMMMQ.

[0046] By using AQ as described above, the inventors have provided the world's first example of polymerization of an n-type conductive polymer in pure water. According to the method of the present invention, a PBFDO water-based ink with a micelle particle size of 120 nm was prepared. This PBFDO water-based ink, which has similar excellent solution processability, can be spin-cast or drop-cast in air to obtain thin film conductivities exceeding 50 S / cm.

[0047] 2 illustrates a second embodiment of the present invention. As noted above, in such an embodiment, the solvent system may include a polar aprotic solvent. In such an embodiment, the method may include: d) performing a solvent exchange to remove the polar aprotic solvent Further includes:

[0048] The polar aprotic solvent may be dimethyl sulfoxide (DMSO), dimethylformamide (DMF), dimethylacetamide (DMA), or a combination thereof. The ratio of water to the polar aprotic solvent is 5:95 to 95:5, preferably 40:60 to 60:40.

[0049] In a second embodiment of the present invention (i.e., the solvent system further comprises a polar aprotic solvent), the catalyst can be a quinone oxidizing agent selected from tetramethylbenzoquinone (TMQ), alkyl- and carboxyl-substituted benzoquinones (AQ), or combinations thereof.

[0050] The present inventors have surprisingly found that carrying out the polymerization reaction in a solvent system comprising water and a polar aprotic solvent promotes the formation of water-soluble PBFDO micelles, which can be further stabilized by adding a surfactant, for example, as disclosed above. Note that in the second embodiment of the present invention, a surfactant is not required. If a surfactant is used, it can be added in step d) above.

[0051] Even after the polar aprotic solvent is completely removed, the PBFDO micelles can still be dissolved in water.

[0052] PBFDO polymerized in a DMSO:water mixed solvent is soluble in water. Even after removing the catalyst and DMSO, this PBFDO still exhibits excellent water solubility. In contrast, PBFDO polymerized via pure DMSO is insoluble in water, even with the use of a surfactant, as shown in Figures 3 and 4. Figures 3 and 4 are photographs of PBFDO aqueous inks with different concentrations. Thus, Figure 3 shows a PBFDO-aqueous ink with a concentration of 1.5 mg / mL, and Figure 4 shows a PBFDO-aqueous ink with a concentration of 0.1 mg / mL. The polymer PBFDO obtained by the polymerization reaction in pure DMSO is insoluble in water with the surfactant PEG. 45However, PBFDO obtained by polymerization in DMSO:water = 4:1 exhibits excellent solubility in water.

[0053] Dynamic light scattering results showed that PBFDO polymerized in pure DMSO had a micelle particle size of 12 μm in water. Using a DMSO:water mixed solvent for the polymerization reaction significantly reduced the particle size of PBFDO micelles to less than 100 nm, with a water content of 15% to 50% by volume (vol%). These results indicate that the solvent system used in the PBFDO polymerization method of the present invention reduces the particle size of PBFDO micelles by 120-240 times and renders PBFDO micelles soluble in water. Furthermore, by using this solvent system, we developed an environmentally friendly PBFDO-based ink with excellent solution processability. Thin films of this ink can be obtained by spin-casting and drop-casting in air. Spin-cast PBFDO thin films exhibit high electrical conductivity exceeding 100 S / cm and excellent air stability.

[0054] Figures 5 and 6 show the apparent hydrodynamic diameters of aqueous PBFDO inks polymerized from DMSO-water mixed solvents with different water contents. The method of the present invention reduces the PBFDO micelle particle size by 50-100 times, making the PBFDO micelles water-soluble and water-processable.

[0055] The polymerization step (i.e., step b) can proceed at a temperature of 20°C to 150°C. In particular, [AQ]- showed much stronger catalytic activity than TMQ. In the second embodiment of the present invention (i.e., the solvent system further comprises a polar aprotic solvent), [AQ]- can catalyze the polymerization of HBFDO to PBFDO at room temperature, which is highly advantageous in terms of cost efficiency.

[0056] As mentioned above, the method of the present invention comprises: c') removing the catalyst by filtration and oxidation to recycle the catalyst. It may further include:

[0057] The method of the present invention may also include additional steps, such as work-up and purification steps, which may be carried out in water.

[0058] While the present invention has been described with reference to various embodiments, those skilled in the art will recognize that modifications may be made without departing from the scope of the invention. The detailed description is to be considered as exemplary, and it is the appended claims, including all equivalents, that are intended to define the scope of the invention.

Claims

1. 1. A method for producing a water-soluble n-type conductive polymer, comprising: a) preparing a reaction solution by adding monomers to a solvent system comprising water in the presence of a catalyst; b) polymerizing the monomer in the reaction solution to obtain an n-type conductive polymer solution; c) post-treating the n-type conductive polymer solution to obtain a water-soluble n-type conductive polymer; The method comprising:

2. wherein the solvent system comprises water, and the process comprises: a') adding a base to the reaction solution and 2. The method of claim 1, wherein step a') is carried out during or immediately after step a).

3. 3. The method of claim 2, wherein the catalyst is an alkyl and carboxyl substituted benzoquinone (AQ).

4. The base is MOH, and M is Li ＋ , Na ＋ , K. ＋ , Me ４ N ＋ , Bu ４ N ＋ 4. The method of claim 2 or 3, wherein the compound is selected from the group consisting of:

5. The method comprises: a'') adding a surfactant to the reaction solution and The method according to any one of claims 2 to 4, wherein step a'') is carried out immediately before, during or immediately after step a').

6. the solvent system further comprising a polar aprotic solvent, the method comprising: d) performing a solvent exchange to remove the polar aprotic solvent 10. The method of claim 1, further comprising:

7. 7. The method of claim 6, wherein the catalyst is a quinone oxidizing agent selected from tetramethylbenzoquinone (TMQ), alkyl and carboxyl substituted benzoquinones (AQ), or combinations thereof.

8. 8. The method of claim 6 or 7, wherein the polar aprotic solvent is dimethyl sulfoxide (DMSO), dimethyl formamide (DMF), dimethyl acetamide (DMA), or a combination thereof.

9. 9. The method according to any one of claims 6 to 8, wherein the ratio of water to the polar aprotic solvent is from 5:95 to 95:

5.

10. The method according to any one of claims 6 to 9, wherein a surfactant is added during step d).

11. The method according to any one of claims 1 to 10, wherein step b) is carried out at a temperature of from 20°C to 150°C.

12. 12. The method of claim 1, wherein the monomer is 3,7-dihydrobenzo[1,2-b:4,5-b]difuran-2,6-dione (HBFDO) and the n-type conductive polymer is poly(benzodifurandione) (PBFDO).

13. The method comprises: c') removing the catalyst by filtration and oxidation to recycle the catalyst. The method of any one of claims 1 to 12, further comprising:

14. A water-soluble n-type conducting polymer obtainable by the method according to any one of claims 1 to 13, wherein said polymer is in the form of micelles with a diameter of less than 200 nm.

15. A water-based ink comprising the water-soluble n-type conductive polymer according to claim 14.

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