Method for obtaining water-processable n-type conducting polymers

Abstract

The present invention provides a method for producing a water-processable n-type conducting polymer, comprising the steps of: a) preparing a reaction solution by adding a monomer to a solvent system comprising a polar aprotic solvent and 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-processable n-type conductive polymer; comprising the catalyst is a carboxyl and / or sulfonyl substituted benzoquinone (AQ); Regarding the method.

Description

[Technical Field]

[0001] The present invention relates to a method for producing water-processable n-type conductive polymers and to water-based inks comprising such water-processable n-type conductive polymers. [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 (CPs) 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-processable n-type conducting polymer, comprising the steps of: a) preparing a reaction solution by adding a monomer to a solvent system comprising a polar aprotic solvent and 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-processable n-type conductive polymer; comprising the catalyst is a carboxyl and / or sulfonyl substituted benzoquinone (AQ); Regarding the method.

[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]

[0010] Furthermore, the method comprises: a') adding a surfactant to the reaction solution It may further include:

[0011] Step a') can be carried out during or immediately after step a). When step a') is present, step a') is carried out before step c). In other words, the 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.

[0012] As will be appreciated from the above, the surfactant is not essential to the method according to the first embodiment.

[0013] The catalyst of the present invention comprises a polar group. In particular, the catalyst of the present invention is selected from carboxyl- and sulfonyl-substituted benzoquinones (AQs). In other words, the catalyst of the present invention comprises a benzoquinone core structure and at least one substituent comprising a carboxyl moiety (-COOH) or a sulfonyl moiety (-SO3H). It should be noted that the catalyst may comprise multiple substituents, which may be the same or different.

[0014] In particular, the catalyst has the following structure: [ka] wherein R0, R1, and R3 are independently H, Me, or —CH2R4R5COOH; R4 and R5 are independently H or Me; R2 is -COOH or -SO2OH) may have:

[0015] A particularly preferred catalyst is 3-(2,4,5-trimethyl-3,6-dioxocyclohexa-1,4-dien-1-yl)propanoic acid (TMQ-PA, R 0 =R 1 =R 3 R = Me, R = R = H, R = -COOH), 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, R = -COOH), 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, R = -COOH), and combinations thereof.

[0016] The catalyst, also known as AQ, can be synthesized by a Michael addition reaction followed by oxidation with N-bromosuccinimide (NBS), as described in detail below. AQ is a highly crystalline, water-insoluble organic acid.

[0017] The catalyst can be prepared using the following synthetic route. [ka]

[0018] Step c) can be carried out by solvent exchange.

[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 without a purification step, even in the presence of surfactants such as polyethylene glycol (PEG). Surprisingly, we found that prepolymerization in a mixture of water and DMSO in the presence of AQ promotes the formation of water-processable PBFDO micelles, which are further stabilized by the addition of surfactants.

[0022] The polar aprotic solvent can be dimethyl sulfoxide (DMSO), dimethylformamide (DMF), dimethylacetamide (DMA), or a combination thereof. The ratio of water to polar aprotic solvent is 5:95 to 95:5, preferably 40:60 to 60:40. In such an embodiment, a solvent exchange step can also be used as a purification step.

[0023] The present inventors have surprisingly found that conducting the polymerization reaction in a solvent system comprising water and a polar aprotic solvent promotes the formation of water-processable 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 during the solvent exchange step by dialysis, as described above.

[0024] The polymerization step (i.e., step b) can proceed at temperatures between 20 and 150 °C. In particular, AQ showed much stronger catalytic activity than TMQ. AQ has been demonstrated to catalyze the polymerization of HBFDO to PBFDO at room temperature, which is a significant advantage in terms of cost efficiency.

[0025] 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.

[0026] The present invention further relates to a water-processable 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 0.2 μm or 0.45 μm PE, Teflon, or PTFE filter. After filtration, the solution should remain colored, indicating that the polymer micelles have passed through the filter.

[0027] The present invention also relates to a water-based ink comprising the water-processable n-type conductive polymer described above.

[0028] 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 approximately 500 S / cm.

[0029] The present invention further relates to an organic optical device or an organic electronic device comprising the above n-type conductive composition.

[0030] 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.

[0031] 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]

[0032] [Figure 1] 1 shows the steps of the method according to the invention; [Figure 2] FIG. 1 shows a PBFDO-water-based ink at a concentration of 1.5 mg / mL. [Figure 3]FIG. 1 shows a PBFDO-water-based ink at a concentration of 0.1 mg / mL. [Figure 4] FIG. 1 shows the apparent hydrodynamic diameter of PBFDO water-based inks polymerized from DMSO-water mixed solvents with different water contents. [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 FTIR spectra of PBFDO synthesized from TMQ and TMQ-PA. [Figure 7] Figure 1 shows atomic force microscope (AFM) height images of the microstructures of PBFDO synthesized from different catalysts: TMQ and TMQ-PA. [Figure 8] Figure 1 shows the Seebeck coefficient measurements of PBFDO obtained from TMQ and TMQ-PA, respectively, where negative values ​​indicate the n-type character of these polymers. [Figure 9] FIG. 1 shows the thermal stability of PBFDO. DETAILED DESCRIPTION OF THE INVENTION

[0033] As mentioned above, the present invention provides a method for producing a water-processable n-type conducting polymer, comprising the steps of: a) preparing a reaction solution by adding a monomer to a solvent system comprising a polar aprotic solvent and 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-processable n-type conductive polymer; The present invention provides a method comprising:

[0034] FIG. 1 illustrates the method of the present invention.

[0035] 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 using a rotary evaporator. 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 (NaSO). The solvent was removed, and the product was crystallized (acetone-hexane) to give 1.5 g of TMQ-PA (80% yield).

[0036] The synthesis of PBFDO from DMSO using TMQ-PA as a catalyst demonstrates its ability to promote polymerization and in situ doping (see above). PBFDO was synthesized in DMSO according to the procedure outlined by Tang and coworkers, as previously described, and the catalytic efficiency of TMQ-PA for the oxidation of HBFDO was investigated and compared with that of TMQ. Fourier transform infrared (FTIR) spectra of PBFDO produced by TMQ-PA and TMQ showed a peak at 1781 cm. -1 The compounds exhibit identical absorption features, including the characteristic carbonyl peak of 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 3

[0037] The electrical conductivity of PBFDO films processed from DMSO and measured by the four-point probe method is approximately 1379 ± 83 S cm for TMQ. -1 , and approximately 1297±98 S cm for TMQ-PA. -1 was measured (Table 1). This result confirms the catalytic efficiency of TMQ-PA for the oxidation of HBFDO in DMSO. [Table 1]

[0038] 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. In particular, the polar protic solvent is DMSO, and the ratio of DMSO to water is 9:1 in steps a) and b), and 1:1 in step c).

[0039] 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-processable 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 c).

[0040] Even after the polar aprotic solvent is completely removed, the PBFDO micelles can still be dissolved in water.

[0041] PBFDO polymerized in a DMSO:water mixed solvent can be processed 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 2 and 3. Figures 2 and 3 show photographs of PBFDO aqueous inks with different concentrations. Thus, Figure 2 shows a PBFDO-aqueous ink with a concentration of 1.5 mg / mL, and Figure 3 shows a PBFDO-aqueous ink with a concentration of 0.1 mg / mL. The polymer PBFDO obtained by the polymerization reaction in pure DMSO was insoluble in water with the surfactant PEG. 45 However, PBFDO obtained by polymerization in DMSO:water = 4:1 exhibits excellent solubility in water.

[0042] 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 suggest 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, making PBFDO micelles processable 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.

[0043] Figures 4 and 5 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-processable.

[0044] The polymerization step (i.e., step b) can proceed at temperatures between 20° C. and 150° C. In particular, AQ exhibited much stronger catalytic activity than TMQ.

[0045] 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.

[0046] The electrical conductivity of PBFDO films processed from DMSO and measured by the four-point probe method is approximately 1379 ± 83 S cm for TMQ. -1 , and approximately 1297±98 S cm for TMQ-PA. -1 was measured (Table 1). The comparable electrical conductivity, morphology, and roughness of the PBFDO films (Figure 7) confirm the catalytic efficiency of TMQ-PA for the oxidation of HBFDO in DMSO.

[0047] As shown in Figure 8, the Seebeck coefficients of the PBFDO films fabricated using TMQ and TMQ-PA were investigated and found to be approximately −20 μV K, consistent with previous reports. -1 The negative sign of the Seebeck coefficient value is consistent with electrons being the majority charge carriers.

[0048] Moreover, both PBFDO films exhibited excellent thermal stability, with no obvious phase transition observed between 25 °C and 250 °C, as shown in Figure 9.

[0049] The present inventors have provided an improved method for the synthesis of PBFDO by using the above-mentioned AQ.

[0050] 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-processable n-type conducting polymer, comprising: a) preparing a reaction solution by adding a monomer to a solvent system comprising a polar aprotic solvent and 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-processable n-type conductive polymer; comprising the catalyst is a carboxyl and / or sulfonyl substituted benzoquinone (AQ); method.

2. The catalyst has the following structure: 【Chemistry 1】 (In the formula, R ０ , R １ , and R ３ are independently H, Me, or —CH ２ R ４ R ５ COOH, R ４ and R ５ are independently H or Me; R ２ is -COOH or -SO ２ OH) 2. The method of claim 1, comprising:

3. The catalyst is 3-(2,4,5-trimethyl-3,6-dioxocyclohexa-1,4-dien-1-yl)propanoic acid (TMQ-PA, R ０ =R １ =R ３ = Me, R ４ =R ５ = H, R ２ =-COOH), 3,3'-(4,5-dimethyl-3,6-dioxocyclohexa-1,4-diene-1,2-diyl)dipropionic acid (AAMMQ, R ０ =R １ = Me, R ３ =-CH ２ R ４ R ５ COOH, R ４ , R ５ = H or Me, R ２ =-COOH), 3,3'-(2,5-dimethyl-3,6-dioxocyclohexa-1,4-diene-1,4-diyl)dipropionic acid (AMAMQ, R １ =R ３ = Me, R ０ =-CH ２ R ４ R ５ COOH, R ４ , R ５ = H or Me, R ２ 3. The method of claim 1, wherein the aryl group is selected from the group consisting of aryl, ...

4. The method comprises: a') adding a surfactant to the reaction solution and The method according to any one of claims 1 to 3, wherein step a') is carried out after step a) but before step c).

5. 5. The method of any one of claims 1 to 4, wherein the polar aprotic solvent is dimethyl sulfoxide (DMSO), dimethyl formamide (DMF), dimethyl acetamide (DMA), or a combination thereof.

6. wherein the solvent system further comprises water, and the process further comprises: d) performing a solvent exchange to remove the polar aprotic solvent The method of any one of claims 1 to 5, further comprising:

7. 7. The method of claim 6, wherein the ratio of water to the polar aprotic solvent is from 5:95 to 95:

5.

8. The method according to any one of claims 1 to 7, wherein step b) is carried out at a temperature of from 20°C to 150°C.

9. 9. 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).

10. A water-processable n-type conducting polymer obtainable by the method according to any one of claims 1 to 9, wherein said polymer is in the form of micelles with a diameter of less than 200 nm.

11. A water-based ink comprising the water-processable n-type conductive polymer of claim 10.

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