Process for obtaining water-soluble n-type conductive polymers

Abstract

The present invention relates to a process for the manufacture of a water-soluble n-type conductive polymer, the process comprising the steps of: a) adding a monomer to a solvent system comprising water in the presence of a catalyst, thereby providing a reaction solution; b) allowing the monomer to polymerize in the reaction solution, thereby obtaining an n-type conductive polymer solution; and c) performing post-treatment on the n-type conductive polymer solution to obtain the water-soluble n-type conductive polymer.

Description

Technical Field

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

[0002] Water-based conductive polymer inks have a wide range of industrial applications, such as 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 an intrinsic conductivity >1 S cm⁻¹. -1 After secondary doping or post-treatment, it reaches >4000 S cm⁻¹ -1 The value of . However, water-based n-type (electron transport) conductive polymers are crucial when considering complementary components in semiconductor devices and circuits.

[0003] The BBL:PEI ethanol-based inks reported in WO 2022 / 106017 and WO 2022 / 106018 represent a first step towards environmentally friendly solvent-based n-type inks. However, several issues partially limit their application. First, ethanol has strict fire-retardant requirements during production, transportation, storage, and use. Furthermore, the inks disclosed in the aforementioned applications are primarily limited to deposition methods such as spray casting and spin casting due to their large particle size. As can be seen from the references cited above, the highest electrical conductivity of BBL:PEI ink is less than 10 S cm⁻¹. -1 This makes them unsuitable for devices that are sensitive to the resistance of thin films.

[0004] Recently, Fei Huang et al. reported a solution-processed n-type conductive polymer, poly(benzodifurandione) (PBFDO), with a conductivity exceeding 2000 S cm⁻¹. -1 (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] Developing a water-based n-type CP ink with high conductivity, processability, and stability comparable to PEDOT:PSS remains a challenging scientific and industrial endeavor with broad 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. Therefore, the present invention relates to a method for manufacturing a water-soluble n-type conductive polymer, the method comprising the following steps:

[0007] a) Adding the monomer to a solvent system containing water in the presence of a catalyst to provide a reaction solution;

[0008] b) Allow the monomer to polymerize in the reaction solution to obtain an n-type conductive polymer solution;

[0009] c) Post-process the n-type conductive polymer solution to obtain a water-soluble n-type conductive polymer.

[0010] This monomer has a centrosymmetric benzene ring as its backbone, active hydrogen, and at least one electron-withdrawing group at the benzyl position. The electron-withdrawing group can be a carbonyl group, carboxyl group, amide group, alkoxyacyl group, etc.

[0011]

[0012] Furthermore, the monomer may be in the form of a heterocyclic portion having a centrally symmetrical benzene ring fused with at least one, preferably at least two, preferably five-membered rings. The monomer further comprises an active hydrogen and at least one electron-withdrawing group at the benzylic position. Specifically, 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.

[0013] 3,7-Dihydrobenzo[1,2-b:4,5-b']difuran-2,6-dione

[0014] 5,7-Dihydropyrrolo[2,3-f]indole-2,6(1H,3H)-dione

[0015] 3,7-Dihydrobenzo[1,2-b:4,5-b']dithiophene-2,6-dione

[0016] Specifically, 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 poly(benzodifurandione) (PBFDO). A general overview of the method of the present invention can be summarized as follows:

[0017]

[0018] TMQ or AQ is a catalyst, as shown below.

[0019]

[0020] According to the first embodiment, the solvent system consists of water. In other words, the solvent system essentially contains only water, for example, at least 99 vol% water. Such an embodiment offers the advantage of a cost-effective and environmentally friendly manufacturing method.

[0021] In an embodiment where the solvent system comprises water, the method further includes the following steps:

[0022] a′) Add alkali to the reaction solution.

[0023] Step a′) can be performed during or immediately after step a). In other words, the base can be added to the reaction solution along with the monomer and catalyst, or immediately after the addition of the monomer and catalyst.

[0024] Furthermore, the method may further include the following steps:

[0025] a") Add a surfactant to the reaction solution.

[0026] Step a′) can be performed during or immediately after step a). In other words, the surfactant can be added to the reaction solution together with the monomer and catalyst, or immediately after the addition of the monomer and catalyst. Furthermore, step a′) can be performed immediately before, immediately after, or simultaneously with step a′).

[0027] As can be understood from the above, surfactants are not necessary for the method according to the first embodiment. However, if the polymer is intended for use in spin casting, surfactants must be added.

[0028] According to the first embodiment, the catalyst can be an alkyl- and carboxyl-substituted benzoquinone (AQ). Such a catalyst can be selected from the group consisting of 3-(2,4,5-trimethyl-3,6-dioxocyclohexyl-1,4-dien-1-yl)propionic acid (AMMMQ, R 0 =R 1 =R 3 =Me), 3,3'-(4,5-dimethyl-3,6-dioxocyclohex-1,4-diene-1,2-diyl)dipropionic acid (AAMMQ, R) 0 =R 1 =Me,R 3 =-CH2R 4 R 5 COOH, R4 R 5 =H or Me), 3,3'-(2,5-dimethyl-3,6-dioxocyclohex-1,4-diene-1,4-diyl)dipropionic acid (AMAMQ, R 1 =R 3 =Me,R 0 =-CH2R 4 R 5 COOH, R 4 R 5 =H or Me) and their combinations.

[0029] The catalyst can be easily separated, recovered, and recycled for further polymerization of PBFDO, as shown in the following scheme.

[0030]

[0031] AQ can be synthesized via Michael addition followed by oxidation with N-bromosuccinimide (NBS), as described in more detail below. AQ is a highly crystalline, water-insoluble organic acid. However, when neutralized with a strong base, AQ is converted to the highly water-soluble [AQ]. - When the solvent system consists of water, [AQ] - In the presence of surfactants, water-insoluble HBFDO monomers can be catalyzed to polymerize into water-soluble PBFDO. Notably, after polymerization, the aqueous solution becomes strongly acidic, and [AQ]... - The ink will be converted into water-insoluble AHQ and AQ, which can be separated from PBFDO ink by simple suction filtration. A mixture of AHQ and AQ can be converted back to pure AQ through gentle oxidation. Therefore, AQ can be easily recycled, thus offering the advantages of cost-effectiveness and low environmental impact.

[0032] According to a first embodiment of the present invention, the base may be MOH, wherein M is selected from Li + Na + K + Me4N + Bu4N + Or a combination thereof.

[0033] The surfactant can be selected from polyethylene glycol (PEG), polyvinylpyrrolidone (PVP), polyvinyl alcohol (PVA), sodium polystyrene sulfonate (PSSNa), poly(styrene sulfonate) acid (PSSH), sodium dodecylbenzene sulfonate (DBSNa), polyquaternium-4 (PQ-4), polyquaternium-10 (PQ-10), polydiallyl dimethyl ammonium chloride (PDADMAC), and polydiallyl diethyl ammonium chloride (PDADEAC). 20. 80, K-carrageenan, PEG-PPG-PEG, polyoxyethylene (10) tridecyl ether, Triton TM X-100 or a combination thereof.

[0034]

[0035] PBFDO, dissolved in DMSO and obtained using the polymerization method reported by Huang et al., precipitated upon the addition of water to the DMSO solution. In other words, PBFDO polymerized in DMSO was insoluble in water even in the presence of surfactants such as polyethylene glycol (PEG). The inventors unexpectedly discovered that initial polymerization in water in the presence of AQ and alkali promoted the formation of water-soluble PBFDO micelles, which were further stabilized by the addition of surfactants.

[0036] According to a second embodiment of the present invention, the solvent system may contain a polar aprotic solvent. In such an embodiment, the method further includes the following steps:

[0037] d) Solvent exchange, which removes the polar aprotic solvent.

[0038] The polar aprotic solvent can be dimethyl sulfoxide (DMSO), dimethylformamide (DMF), dimethylacetamide (DMA), or a combination thereof. The ratio between water and the polar aprotic solvent can be 5:95 to 95:5, preferably 40:60 to 60:40.

[0039] According to a second embodiment of the invention, the solvent system comprises a polar aprotic solvent, and the catalyst may be a quinone oxidant selected from tetramethylbenzoquinone (TMQ), alkyl- and carboxyl-substituted benzoquinone (AQ), or a combination thereof.

[0040] The inventors have unexpectedly discovered that polymerization in a solvent system containing water and a polar aprotic solvent promotes the formation of water-soluble PBFDO micelles, which can be further stabilized by adding surfactants (e.g., as disclosed above). It should be noted that, according to a second embodiment of the invention, a surfactant is not necessary. If used, the surfactant can be added during step d).

[0041] Even after complete removal of the polar aprotic solvent, PBFDO micelles remain soluble in water.

[0042] The polymerization step (i.e., step b) can be carried out at temperatures ranging from 20°C to 150°C. In particular, [AQ]- exhibits much stronger catalytic activity compared to TMQ. According to a second embodiment of the invention, wherein the solvent system comprises a polar aprotic solvent, [AQ]- can catalyze the polymerization of HBFDO to PBFDO at room temperature, which is a significant advantage in terms of cost-effectiveness.

[0043] As mentioned above, the method of the present invention may further include the following steps:

[0044] c') The catalyst is removed by filtration and oxidation and then recycled.

[0045] Finally, the method of the present invention may include additional steps, such as post-treatment and purification steps. Such steps may also be performed in water.

[0046] The present invention further relates to a water-soluble n-type conductive polymer obtained by the method described above. This polymer can be in the form of micelles having a diameter of less than 200 nm. The particle size can be readily verified by passing the polymer solution through a 20 μm filter; the presence of color in the solution indicates that the polymer micelles passed through the filter.

[0047] Furthermore, the present invention relates to a water-based ink comprising a water-soluble n-type conductive polymer as mentioned above.

[0048] Therefore, the n-type conductive ink of the present invention can be spin-coated or drop-cast in air and at ambient temperature to form a film with a thickness of 1 nm to 1 cm, more preferably 10 nm to 10 μm. Such a film can exhibit a conductivity of approximately 5 S / cm.

[0049] The present invention further relates to an organic optical or electronic device comprising the n-type conductive composition described above.

[0050] 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 OECT), thermoelectric devices, ternary logic inverters, OPV, OLED, organic supercapacitors, batteries, fuel cells, sensors, and memories. Attached Figure Description

[0051] Embodiments of the present invention will now be described by way of example with reference to the accompanying drawings, wherein:

[0052] Figure 1 The steps of a method according to a first embodiment of the present invention are shown;

[0053] Figure 2The steps of a method according to a second embodiment of the present invention are shown;

[0054] Figure 3 A PBFDO-water ink with a concentration of 1.5 mg / ml was depicted;

[0055] Figure 4 A PBFDO-water ink with a concentration of 0.1 mg / ml was depicted;

[0056] Figures 5 to 6 The apparent hydrodynamic diameters of PBFDO water-based inks polymerized from DMSO-water mixed solvents with different water contents are shown. Detailed Implementation

[0057] As mentioned above, the present invention provides a method for manufacturing a water-soluble n-type conductive polymer, the method comprising the following steps:

[0058] a) Adding the monomer to a solvent system containing water in the presence of a catalyst to provide a reaction solution;

[0059] b) Allow the monomer to polymerize in the reaction solution to obtain an n-type conductive polymer solution;

[0060] c) Post-process the n-type conductive polymer solution to obtain a water-soluble n-type conductive polymer.

[0061] according to Figure 1 The first embodiment shown in the diagram uses a solvent system composed of water. In other words, the solvent system essentially contains only water, for example, at least 99 vol% water. Such an embodiment offers the advantage of a cost-effective and environmentally friendly manufacturing method.

[0062] As in Figure 1 As can be seen in the text, the method further includes the following steps:

[0063] a′) Add alkali and surfactant to the reaction solution.

[0064] Step a′) can be performed during or immediately after step a). In other words, the base and surfactant can be added to the reaction solution together with the monomer and catalyst, or immediately after the addition of the monomer and catalyst.

[0065] According to the first embodiment, the catalyst can be an alkyl- and carboxyl-substituted benzoquinone (AQ). Such a catalyst can be selected from the group consisting of 3-(2,4,5-trimethyl-3,6-dioxocyclohexyl-1,4-dien-1-yl)propionic acid (AMMMQ, R 0 =R 1 =R 3=Me), 3,3'-(4,5-dimethyl-3,6-dioxocyclohex-1,4-diene-1,2-diyl)dipropionic acid (AAMMQ, R) 0 =R 1 =Me,R 3 =-CH2R 4 R 5 COOH, R 4 R 5 =H or Me), 3,3'-(2,5-dimethyl-3,6-dioxocyclohex-1,4-diene-1,4-diyl)dipropionic acid (AMAMQ, R 1 =R 3 =Me,R 0 =-CH2R 4 R 5 COOH, R 4 R 5 =H or Me) and their combinations.

[0066] The catalyst can be easily separated, recovered, and recycled for further polymerization of PBFDO, as shown in the following scheme.

[0067]

[0068] According to a specific embodiment of the present invention, the catalyst can be synthesized as follows: Methanesulfonic acid (10 mL) is 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) are added with stirring. The reaction is continued at 70 °C for 90 min, and then the mixture is diluted to 100 mL of water and extracted three times with ethyl acetate. The extract is washed with water, saturated NaHCO3, and saturated NaCl, and dried (Na2SO4). The solvent is removed by rotary evaporation. The residue is purified by silica gel chromatography to give pure solid lactone 3MCQ (0.81 g, 60% yield). A solution of NBS (1.63 g, 9.16 mmol) in 18 mL of acetonitrile is added dropwise to a solution of lactone 3MCQ (1.8 g, 8.73 mmol) in 90 mL of 10% acetonitrile aqueous solution. The reaction mixture is stirred at 25 °C for 1 h, and the solvent is removed by rotary evaporation. The residue was diluted with water and extracted with multiple fractions of ether. The combined ether extracts were washed with water and brine and dried (using Na2SO4). The solvent was removed and crystallized (acetone-hexane) to give 1.5 g of product AMMMQ (80% yield).

[0069]

[0070] Water-soluble PBFDO micelles were synthesized as follows. NaOH (0.42 ml, 0.5 M) was added to a suspension of catalyst AMMMQ (46.75 mg, 0.21 mmol) in 1.6 ml of water, and the suspension turned into a bright yellow solution after stirring for 10 min. Then, surfactant PDADMAC (100 mg, 0.63 mmol) and monomer HBFDO (40 mg, 0.21 mmol) were added to the reaction mixture and stirred overnight at 100 °C. The catalyst was separated by filtration, and the filtrate PBFDO-water solution was transferred to a dialysis bag and dialyzed in deionized water for 2 days to remove oligomers, yielding PBFDO-water ink. PBFDO-water ink can be diluted or concentrated to 1-50 mg / mL by centrifugal dialysis for use in spin casting, drip casting, and other film processing methods.

[0071] The catalyst was recycled as follows. A solution of FeCl3·6H2O (215 mg, 0.8 mmol) in 1 mL of H2O was added to 5 mL of the separated AMMMQ / AMMMHQ (45 mg, 0.2 mmol, 95% recovery) in acetonitrile:H2O (1:1). The reaction mixture was stirred at room temperature for 10 min and diluted with water, then extracted with multiple ether extracts. The combined ether extracts were washed with water and brine and dried (Na2SO4). The solvent was removed and crystallized (acetone-hexane) to give 41 mg (92% yield) of the catalyst AMMMQ.

[0072] Using the AQ described above, the inventors have provided the world's first instance of polymerizing n-type conductive polymers in pure water. According to the method of the invention, PBFDO water-based inks with a micelle particle size of 120 nm have been manufactured. PBFDO-water inks, exhibiting similarly excellent solution processability, can be spin-cast and drop-cast in air to achieve film conductivity exceeding 50 S / cm.

[0073] Figure 2 The method of the present invention according to a second embodiment is described. As mentioned above, according to this embodiment, the solvent system may contain a polar aprotic solvent. In such an embodiment, the method further includes the following steps:

[0074] d) Solvent exchange, which removes the polar aprotic solvent.

[0075] The polar aprotic solvent can be dimethyl sulfoxide (DMSO), dimethylformamide (DMF), dimethylacetamide (DMA), or a combination thereof. The ratio between water and the polar aprotic solvent can be 5:95 to 95:5, preferably 40:60 to 60:40.

[0076] According to a second embodiment of the invention, the solvent system comprises a polar aprotic solvent, and the catalyst may be a quinone oxidant selected from tetramethylbenzoquinone (TMQ), alkyl- and carboxyl-substituted benzoquinone (AQ), or a combination thereof.

[0077] The inventors have unexpectedly discovered that polymerization in a solvent system containing water and a polar aprotic solvent promotes the formation of water-soluble PBFDO micelles, which can be further stabilized by adding surfactants (e.g., as disclosed above). It should be noted that, according to a second embodiment of the invention, a surfactant is not necessary. If used, the surfactant can be added during step d).

[0078] Even after complete removal of the polar aprotic solvent, PBFDO micelles remain soluble in water.

[0079] PBFDO polymerized via a DMSO:water mixed solvent is soluble in water. Even after removing the catalyst and DMSO, this PBFDO still exhibits excellent solubility in water. Conversely, PBFDO polymerized via pure DMSO is insoluble in water even with the use of surfactants, such as... Figure 3 and Figure 4 As shown in the document. Figure 3 and Figure 4 These are photographs of PBFDO-water-based inks at different concentrations. Therefore, Figure 3 A PBFDO-water ink with a concentration of 1.5 mg / mL was depicted, and Figure 4 A PBFDO-water ink with a concentration of 0.1 mg / mL was demonstrated. The polymer PBFDO, obtained by polymerization in pure DMSO, is insoluble in water, even when using the surfactant PEG. 45 The same applies in this case, and PBFDO obtained by polymerization in DMSO:water = 4:1 shows excellent solubility in water.

[0080] Dynamic light scattering results showed that PBFDO polymerized in pure DMSO exhibited a micelle size of 12 μm in water. Using a DMSO:water mixed solvent for the polymerization reaction, the PBFDO micelle size could be significantly reduced to below 100 nm, with a water content of 15 vol% to 50 vol%. These results imply that the solvent system used for PBFDO polymerization in the method of this invention can reduce the PBFDO micelle size to 1 / 240–1 / 120 of its original size and make the PBFDO micelles soluble in water. Furthermore, using the solvent system described above, an environmentally friendly PBFDO-water ink with excellent solution processability was developed. Such an ink can be spin-cast and drop-cast in air to obtain films. The spin-cast PBFDO films exhibited high conductivity exceeding 100 S / cm and excellent air stability.

[0081] Figure 5 and Figure 6 The apparent hydrodynamic diameters of PBFDO water-based inks polymerized from DMSO-water mixed solvents with varying water contents are shown. The method of this invention reduces the micelle size of PBFDO to 1 / 100-1 / 50 of its size, making the PBFDO micelles water-soluble and water-processable.

[0082] The polymerization step (i.e., step b) can be carried out at temperatures ranging from 20°C to 150°C. In particular, [AQ]- exhibits much stronger catalytic activity compared to TMQ. According to a second embodiment of the invention, wherein the solvent system comprises a polar aprotic solvent, [AQ]- can catalyze the polymerization of HBFDO to PBFDO at room temperature, which is a significant advantage in terms of cost-effectiveness.

[0083] As mentioned above, the method of the present invention may further include the following steps:

[0084] c') The catalyst is removed by filtration and oxidation and then recycled.

[0085] Finally, the method of the present invention may include additional steps, such as post-treatment and purification steps. Such steps may also be performed in water.

[0086] Although the invention has been described with reference to several embodiments, those skilled in the art will recognize that changes can be made without departing from the scope of the invention. It is intended that the detailed description be regarded as illustrative and that the appended claims (including all equivalents) are intended to define the scope of the invention.

Claims

1. A method for manufacturing a water-soluble n-type conductive polymer, the method comprising the following steps: a) Adding the monomer to a solvent system containing water in the presence of a catalyst to provide a reaction solution; b) Allow the monomer to polymerize in the reaction solution to obtain an n-type conductive polymer solution; c) Post-process the n-type conductive polymer solution to obtain a water-soluble n-type conductive polymer.

2. The method according to claim 1, wherein, The solvent system is composed of water, and the method further includes the following steps: a′) Add alkali to the reaction solution. Step a′) is performed during or immediately after step a).

3. The method according to claim 2, wherein, The catalyst is an alkyl- and carboxyl-substituted benzoquinone (AQ).

4. The method according to claim 2 or 3, wherein, The base is MOH, where M is selected from Li. + Na + K + Me4N + Bu4N + Or a combination thereof.

5. The method according to any one of claims 2 to 4, further comprising the following steps: a) Add a surfactant to the reaction solution. Step a") is performed immediately before, during, or immediately after step a').

6. The method according to claim 1, wherein, The solvent system further comprises a polar aprotic solvent, and the method further comprises the following steps: d) Solvent exchange, which removes the polar aprotic solvent.

7. The method according to claim 6, wherein, The catalyst is a quinone oxidant selected from the following: tetramethylbenzoquinone (TMQ), alkyl- and carboxyl-substituted benzoquinone (AQ), or a combination thereof.

8. The method according to claim 6 or 7, wherein, The polar aprotic solvent is dimethyl sulfoxide (DMSO), dimethylformamide (DMF), dimethylacetamide (DMA), or a combination thereof.

9. The method according to any one of claims 6 to 8, wherein, The ratio of water to the polar aprotic solvent is 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 the preceding claims, wherein, Step b) is performed at a temperature between 20°C and 150°C.

12. The method according to any one of the preceding claims, 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 according to any one of the preceding claims, wherein, The method further includes the following steps: c') The catalyst is removed by filtration or oxidation and then recycled.

14. A water-soluble n-type conductive polymer obtained by the method according to any one of claims 1 to 13, wherein, The 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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