A water-alcohol-soluble electrochromic polymer, and a preparation method and application thereof

Abstract

The application adopts arylization polycondensation to prepare the water-alcohol soluble electrochromic polymer, the polymer has ammonium side chains, can realize environment-friendly solvent processing such as water or alcohol, and improves the electrochromic response speed of the polymer. The application also provides an electrochromic polymer film prepared from the electrochromic polymer, which can realize stable and reversible transformation from neutral state coloring to high transmission of the oxidized state under low voltage, and has potential application value in the fields of display, smart window, electronic paper and the like.

Description

(I) Technical Field

[0001] This invention relates to a water- and alcohol-soluble electrochromic polymer, its preparation method, and its application in the preparation of electrochromic polymer films. (II) Background Technology

[0002] Electrochromism (EC) refers to the phenomenon that the optical properties of a material, such as transmittance, reflectance, and absorptivity, undergo stable and reversible changes under the action of an applied electric field. Macroscopically, this manifests as reversible changes in color and transparency.

[0003] Electrochromic materials are mainly classified into inorganic electrochromic materials, organic small-molecule electrochromic materials, and polymer electrochromic materials. Among them, polymer electrochromic materials (PECs) are widely studied due to their easily modifiable structure, controllable band structure, good processing performance, and excellent overall electrochromic properties, making them highly valuable for applications in fields such as smart windows, flat panel displays, and information tags. However, most existing PEC materials are soluble in organic solutions, posing certain environmental hazards and hindering practical applications.

[0004] Currently, water- and alcohol-soluble PEC materials can be mainly classified into sulfonates, carboxylates, and ammonium compounds. A few reports have been made on sulfonates and carboxylates, and their basic physicochemical properties and electrochromic properties have been studied to some extent []. However, there are no reports on ammonium-based water- and alcohol-soluble PEC materials. Furthermore, in ammonium-based materials, N and O in ITO form hydrogen bonds, which reduces the dipole moment between the material and the interface, thus decreasing the electrochromic response time. Therefore, developing ammonium-based water- and alcohol-soluble PEC materials is significant for studying the basic electrochromic properties and applications of ammonium-based materials. (III) Summary of the Invention

[0005] The first objective of this invention is to provide an electrochromic polymer having ammonium side chains and good solubility in an aqueous alcohol solvent (containing 5% acetic acid).

[0006] A second objective of this invention is to provide a method for preparing electrochromic polymers.

[0007] A third objective of this invention is to provide an electrochromic polymer film.

[0008] The objective of this invention is achieved through the following technical solution:

[0009] In a first aspect, the present invention provides an electrochromic polymer, said polymer being one of the following polymers:

[0010]

[0011] Where a1 and a2 are 0 or 1 respectively, m1 and m2 are integers from 3 to 14; X and Y are redox active groups;

[0012] The X is one of the following groups:

[0013]

[0014] The Y group is one of the following groups:

[0015]

[0016] The electrochromic polymer has a number-average molecular weight Mn of 2000 to 200000, the molecular weight is controlled by the polymerization reaction time, and the polydispersity index D of 1.0 to 5.0.

[0017] Preferably, the number-average molecular weight Mn of the electrochromic polymer is 10,000 to 50,000.

[0018] In a second aspect, the present invention provides a method for preparing an electrochromic polymer of formula (I), the method being as follows: monomer 1, monomer 2, organic acid, inorganic weak base, ligand and palladium catalyst of formula 1 are added to an organic solvent and reacted at 60-100°C for 6-72 h (preferably at 80°C for 12-36 h, most preferably at 80°C for 24 h), and the resulting reaction mixture is post-treated to obtain the electrochromic polymer of formula (I);

[0019]

[0020] The monomer 2 is one of the following compounds:

[0021]

[0022] In formulas 1 and (I), a1 is 0 or 1, and m1 is an integer from 3 to 14; in formula (I), X is one of the following groups:

[0023]

[0024] The organic acid is one or a mixture of two of neopentanoic acid and 1-adamantanecarboxylic acid; the inorganic weak base is one or a mixture of two or more of potassium carbonate, sodium carbonate, potassium bicarbonate, and sodium bicarbonate; the ligand is one or a mixture of two of tricyclohexylphosphine fluoroborate and tris(2-methoxyphenyl)phosphine; the palladium catalyst is one or a mixture of two or more of tris(dibenzylideneacetone)dipalladium(O)-chloroform adduct, palladium acetate, and dichlorodi(triphenylphosphine)palladium; the molar ratio of monomer 1, monomer 2, organic acid, inorganic weak base, ligand, and palladium catalyst shown in Formula 1 is 1:1:0.3-0.5:2-3:0.03-0.1:0.03-0.1 (preferably 1:1:0.3:2.5:0.03:0.03).

[0025] Preferably, the organic solvent is one or a mixture of two or more of tetrahydrofuran, N-methylpyrrolidone, dimethylformamide, and dimethylacetamide.

[0026] Furthermore, the volume of the organic solvent, based on the total amount of monomer 1 and monomer 2 shown in Formula 1, is 1 to 20 L / mol (preferably 2.5 L / mol).

[0027] Further, the post-processing is as follows: the reaction mixture is poured into methanol, filtered, the filter cake is dried, and extracted sequentially with methanol, acetone, hexane and chloroform. The polymer dissolved in chloroform is collected, evaporated, and the electrochromic polymer shown in formula (I) is obtained.

[0028] Furthermore, monomer 1 shown in Formula 1 is prepared by the following method:

[0029] The synthesis of monomer 1 shown in Equation 1 is described in reference [Adv. Mater. 2011, 23, 1665–1669], and the synthesis process is as follows:

[0030]

[0031] The specific synthesis process is as follows:

[0032] Compounds A1 and A2, along with tetrabutylammonium iodide (TBAI), were added to a 50% sodium hydroxide aqueous solution and reacted at 60°C for 12 h. The resulting reaction mixture was purified by column chromatography to obtain compound A3. The molar ratio of compounds A1, A2, and tetrabutylammonium iodide was 1:4:0.1. The volume of the sodium hydroxide aqueous solution was 3 L / mol based on the molar amount of compound A1.

[0033] Compounds A3 and A4 were added to DMF and reacted at 160°C for 12 h. The resulting reaction mixture was purified by column chromatography to obtain monomer 1 as shown in Formula 1. The molar ratio of compounds A3 and A4 was 1:6. The volume of DMF was 10 L / mol based on the molar amount of compound A3.

[0034] Thirdly, the present invention provides a method for preparing the electrochromic polymer shown in formula (II), the method being as follows: monomer 3, monomer 4, organic acid, inorganic weak base, ligand and palladium catalyst shown in formula 3 are added to an organic solvent and reacted at 60-100°C for 6-72 h (preferably at 80°C for 12-36 h, most preferably at 80°C for 24 h), and the resulting reaction mixture is post-treated to obtain the electrochromic polymer shown in formula (II);

[0035]

[0036] The monomer 4 is one of the following compounds:

[0037]

[0038] In formulas 3 and (II), a2 is 0 or 1, and m2 is an integer from 3 to 14; in formula (II), Y is one of the following groups:

[0039]

[0040] The organic acid is one or a mixture of two of neopentanoic acid and 1-adamantanecarboxylic acid; the inorganic weak base is one or a mixture of two or more of potassium carbonate, sodium carbonate, potassium bicarbonate, and sodium bicarbonate; the ligand is one or a mixture of two of tricyclohexylphosphine fluoroborate and tris(2-methoxyphenyl)phosphine; the palladium catalyst is one or a mixture of two or more of tris(dibenzylacetone)dipalladium(O)-chloroform adduct, palladium acetate, and dichlorodi(triphenylphosphine)palladium; the molar ratio of monomer 3, monomer 4, organic acid, inorganic weak base, ligand, and palladium catalyst shown in Formula 3 is 1:1:0.3-0.5:2-3:0.03-0.1:0.03-0.1 (preferably 1:1:0.3:2.5:0.03:0.03).

[0041] Preferably, the organic solvent is one or a mixture of two or more of tetrahydrofuran, N-methylpyrrolidone, dimethylformamide, and dimethylacetamide.

[0042] Furthermore, the volume of the organic solvent, based on the total amount of monomers 3 and 4 shown in Formula 3, is 1 to 20 L / mol (preferably 2.5 L / mol).

[0043] Further, the post-processing is as follows: the reaction mixture is poured into methanol, filtered, the filter cake is dried, and extracted sequentially with methanol, acetone, hexane and chloroform. The polymer dissolved in chloroform is collected, evaporated, and the electrochromic polymer shown in formula (II) is obtained.

[0044] Furthermore, monomer 3 shown in Formula 3 is prepared according to the following method:

[0045] The synthesis of monomer 3 is described in reference [J. Mater. Chem. C, 2020, 8, 15158-15167], and the synthesis process is as follows:

[0046]

[0047] The specific synthesis process is as follows:

[0048] Compounds B1 and B2 were added to toluene containing p-toluenesulfonic acid (pTSA) and reacted at 110°C for 12 h. The resulting reaction mixture was purified by column chromatography to obtain compound B3. The molar ratio of compounds B1, B2, and pTSA was 1:4:0.1. The volume of toluene, based on the amount of compound B1, was 2 L / mol.

[0049] Compounds B3 and A4 were added to DMF solvent and reacted at 160°C for 12 h. The resulting reaction mixture was purified by column chromatography to obtain monomer 3. The molar ratio of compounds B3 to A4 was 1:6. The volume of toluene was 2 L / mol based on the molar amount of compound B3.

[0050] Fourthly, the present invention provides a method for preparing an electrochromic polymer of formula (II), the method being as follows: monomer 5, monomer 6, organic acid, inorganic weak base, ligand and palladium catalyst of formula 5 are added to an organic solvent and reacted at 60-100°C for 6-72 h (preferably at 80°C for 12-36 h, most preferably at 80°C for 24 h), and the resulting reaction mixture is post-treated to obtain the electrochromic polymer of formula (II);

[0051]

[0052] The monomer 6 is one of the following compounds:

[0053]

[0054] In formulas 5 and (II), a2 is 0 or 1, and m2 is an integer from 3 to 14; in formula (II), Y is one of the following groups:

[0055]

[0056] The organic acid is one or a mixture of two of neopentanoic acid and 1-adamantanecarboxylic acid; the inorganic weak base is one or a mixture of two or more of potassium carbonate, sodium carbonate, potassium bicarbonate, and sodium bicarbonate; the ligand is one or a mixture of two of tricyclohexylphosphine fluoroborate and tris(2-methoxyphenyl)phosphine; the palladium catalyst is one or a mixture of two or more of tris(dibenzylacetone)dipalladium(O)-chloroform adduct, palladium acetate, and dichlorodi(triphenylphosphine)palladium; the molar ratio of monomer 5, monomer 6, organic acid, inorganic weak base, ligand, and palladium catalyst shown in Formula 5 is 1:1:0.3-0.5:2-3:0.03-0.1:0.03-0.1 (preferably 1:1:0.3:2.5:0.03:0.03).

[0057] Preferably, the organic solvent is one or a mixture of two or more of tetrahydrofuran, N-methylpyrrolidone, dimethylformamide, and dimethylacetamide.

[0058] Furthermore, the volume of the organic solvent, based on the total amount of monomers 5 and 6 shown in Formula 5, is 1 to 20 L / mol (preferably 2.5 L / mol).

[0059] Further, the post-processing is as follows: the reaction mixture is poured into methanol, filtered, the filter cake is dried, and extracted sequentially with methanol, acetone, hexane and chloroform. The polymer dissolved in chloroform is collected, evaporated, and the electrochromic polymer shown in formula (II) is obtained.

[0060] Furthermore, monomer 5 shown in Formula 5 is prepared according to the following method:

[0061] The synthesis process of monomer 5 is shown below:

[0062]

[0063] Monomer 3 was added to a dichloromethane (DCM) solution containing N-bromodiimide (NBS) and reacted at room temperature for 6 h. The resulting reaction mixture was purified by column chromatography to obtain monomer 5. The molar ratio of monomer 3 to NBS was 1:2.5. The volume of the dichloromethane (DCM) solution containing N-bromodiimide (NBS) was 2 L / mol based on the molar amount of monomer 3.

[0064] Fifthly, the present invention provides an application of the above-mentioned electrochromic polymer in the preparation of electrochromic polymer films.

[0065] Preferably, the electrochromic polymer film is obtained by solution processing of the electrochromic polymer.

[0066] Specifically, the application involves dissolving the electrochromic polymer in a solvent to obtain a polymer solution, and then coating the polymer solution onto a conductive substrate to obtain the electrochromic polymer film. The solvent is a methanol solution of acetic acid with a volume fraction of 3-20% (preferably 5%), an ethanol solution of acetic acid with a volume fraction of 3-20% (preferably 5%), or an aqueous solution of acetic acid with a volume fraction of 3-20% (preferably 5%). The concentration of the electrochromic polymer in the polymer solution is 3-10 mg / mL (preferably 5 mg / mL).

[0067] In this invention, the coating process can be spraying, spin coating, screen printing, etc. The conductive substrate can be ITO glass, FTO glass, ITO-PET substrate, or FTO-PET substrate, etc.

[0068] The electrochromic polymer film obtained by this invention has potential application value in fields such as smart windows, displays, and electronic paper.

[0069] Compared with existing technologies, the present invention has the following advantages:

[0070] (1) The polymer involved in this invention has ammonium side chains and has good solubility in environmentally friendly solvents such as water and alcohol. Its thin film material can be prepared on a large area by environmentally friendly solution processing method.

[0071] (2) The polymers involved in this invention have ammonium side chains, which can improve the electrochromic response speed of the polymer compared with alkyl side chains.

[0072] (3) The polymer film prepared by the present invention can achieve a stable and reversible transition from neutral state coloring to oxidized state with high transmittance under low voltage (around 1.0V), and has potential application value in the fields of displays, smart windows, and mobile phone cases. (iv) Description of the attached drawings

[0073] Figure 1 Optical absorption of the polymer film (P1) prepared in Example 1 at different voltages;

[0074] Figure 2 The curve showing the transmittance of the polymer film (P1) prepared in Example 1 as a function of time under multiple potential steps from 0 to 1.1V at a specific wavelength;

[0075] Figure 3 The curves showing the transmittance of the polymer film prepared in Example 1 as a comparison under multiple potential steps from 0 to 1.1V at a specific wavelength as a function of time.

[0076] Figure 4 The optical absorption of the polymer film prepared in Example 2 under different voltages;

[0077] Figure 5 The curve showing the transmittance of the polymer film prepared in Example 2 as a function of time under multiple potential steps from 0 to 1.1V at a specific wavelength;

[0078] Figure 6 The optical absorption of the polymer film prepared in Example 3 under different voltages;

[0079] Figure 7 The curve showing the transmittance of the polymer film prepared in Example 3 as a function of time under multiple potential steps from 0 to 1.1V at a specific wavelength;

[0080] Figure 8 The optical absorption of the polymer film prepared in Example 4 under different voltages;

[0081] Figure 9 The curve showing the transmittance of the polymer film prepared in Example 4 as a function of time under multiple potential steps from -0.4 to 0.8 V at a specific wavelength;

[0082] Figure 10 The optical absorption of the polymer film prepared in Example 5 under different voltages;

[0083] Figure 11 The curve showing the transmittance of the polymer film prepared in Example 5 as a function of time under multiple potential steps from -0.2 to 0.9 V at a specific wavelength; (V) Detailed Implementation

[0084] The technical solution of the present invention will be further described below with reference to specific embodiments, but the scope of protection of the present invention is not limited thereto.

[0085] Example 1

[0086] The synthesis and molecular structure of the conjugated polymers used are shown below:

[0087] The synthesis process of this polymer is as follows:

[0088]

[0089] FN (0.634 g, 1 eq.) and PBTP (0.500 g, 1 eq.) were added to 5 ml of THF solution containing neopentanoic acid (30 mg, 0.3 eq.) and cesium carbonate (0.812 g, 2.5 eq.). Finally, ligand P(o-MeOPh)3 (10 mg, 0.03 eq.) and catalyst Pd(dba)3 were added. .CHCl3 (30 mg, 0.03 eq.) was reacted at 80 °C for 24 hours. After the reaction, the solution was poured into 200 ml of methanol, filtered, and the filter cake was dried. Extraction was performed sequentially with methanol, acetone, hexane, and chloroform. The polymer dissolved in chloroform was collected and evaporated to dryness. The polymer GPC test results were as follows (Mn = 12.2 kDa, D = 2.01).

[0090] Preparation of polymer films:

[0091] The polymer was dissolved in methanol (containing 5% acetic acid by volume) to obtain a polymer solution, which was then sprayed onto an ITO substrate to form a film. The concentration of the polymer solution was 5 mg / ml, and the volume of the solution was 0.5 ml for each spraying.

[0092] Electrochromic properties of the obtained polymer film: Colorimetric measurements were performed on the polymer film at 0V neutral and 1.1V oxidized states. The results were: neutral state L* = 56.7, a* = 39.35, b* = -12.89; oxidized state L* = 77.7, a* = 4.05, b* = 3.79. Using an electrochemical workstation coupled with a UV-Vis spectrophotometer, the UV-Vis absorption of the prepared film at different voltages was measured in 0.1M tetrabutylammonium hexafluorophosphate / acetonitrile solution. The transmittance at specific wavelengths was also measured in relation to time. The data processing results are as follows: Figure 1 and 2 As shown. From Figure 1 Colorimetric testing shows that the polymer film is magenta in a neutral state at 0V, and exhibits high transmittance after oxidation at 1.1V. From... Figure 2 It can be seen that the contrast ratio of the film at 550 nm is 37%, and the coloring time and fading time are 1.5 s and 0.4 s, respectively. The test results show that this polymer film has high contrast and fast response time. Compared with the polymers described below, the amine side chains not only enhance the polymer's solubility in methanol but also improve the electrochromic response speed of the polymer film.

[0093] For comparison, the synthesis process of polymers without amine side chains is as follows:

[0094]

[0095] F (0.492 g, 1 eq.) and PBTP (0.500 g, 1 eq.) were added to a 5 mL THF solution containing neopentanoic acid (30 mg, 0.3 eq.) and cesium carbonate (0.812 g, 2.5 eq.). Finally, ligand P(o-MeOPh)3 (10 mg, 0.03 eq.) and catalyst Pd(dba)3 were added. .CHCl3 (30 mg, 0.03 eq.) was reacted at 80 °C for 24 hours. After the reaction, the solution was poured into 200 ml of methanol, filtered, and the filter cake was dried. Extraction was performed sequentially with methanol, acetone, hexane, and chloroform. The polymer dissolved in chloroform was collected and evaporated to dryness. The polymer GPC test results were as follows (Mn = 39.9 kDa, D = 2.66).

[0096] Preparation of polymer films:

[0097] The polymer was dissolved in chloroform and sprayed onto an ITO substrate to form a film. The solution concentration was 5 mg / ml, and the solution volume was 0.5 ml for each spraying.

[0098] Electrochromic properties of the obtained polymer film: Using an electrochemical workstation coupled with a UV-Vis spectrophotometer, the transmittance of the prepared film at a specific wavelength was measured in a 0.1 M tetrabutylammonium hexafluorophosphate / acetonitrile solution as a function of time. The data processing results are as follows: Figure 3 As shown. From Figure 3 It can be seen that the coloring time and fading time are 1.9s and 0.5s, respectively. The test results show that the coloring and fading times of this polymer film are both slower than those of polymers with amine side chains.

[0099] Example 2

[0100] The synthesis and molecular structure of the conjugated polymers used are shown below:

[0101] The synthesis process of this polymer is as follows:

[0102]

[0103] FN (0.634 g, 1 eq.) and PSeP (0.547 g, 1 eq.) were added to 5 ml of THF solution containing neopentanoic acid (30 mg, 0.3 eq.) and cesium carbonate (0.812 g, 2.5 eq.). Finally, ligand P(o-MeOPh)3 (10 mg, 0.03 eq.) and catalyst Pd(dba)3 were added. . CHCl3 (30 mg, 0.03 eq.) was reacted at 80 °C for 24 hours. After the reaction, the solution was poured into 200 ml of methanol, filtered, and the filter cake was dried. Extraction was performed sequentially with methanol, acetone, hexane, and chloroform. The polymer dissolved in chloroform was collected and evaporated to dryness. The polymer GPC test results were as follows (Mn = 9.2 kDa, D = 2.43).

[0104] Preparation of polymer films:

[0105] The polymer was dissolved in methanol (containing 5% acetic acid by volume) and sprayed onto an ITO substrate to form a film. The solution concentration was 5 mg / ml, and the solution volume was 0.5 ml for each spraying.

[0106] Electrochromic properties of the obtained polymer film: Colorimetric measurements were performed on the polymer film at 0V neutral and 1.1V oxidized states. The results were: neutral state L* = 49.55, a* = -11.5, b* = -17.96; oxidized state L* = 75.46, a* = -3.77, b* = 2.72. Using an electrochemical workstation coupled with a UV-Vis spectrophotometer, the UV-Vis absorption of the prepared film at different voltages was measured in 0.1M tetrabutylammonium hexafluorophosphate / acetonitrile solution. The transmittance at specific wavelengths was also measured in relation to time. The data processing results are as follows: Figure 4 and 5 As shown. From Figure 4 Colorimetric testing shows that the polymer film is blue in a neutral state at 0V, and exhibits high transmittance after oxidation at 1.1V. From... Figure 5 It can be seen that the contrast ratio of the film at 585nm is 36%, and the coloring time and fading time are 2.2s and 0.5s, respectively. The test results show that this polymer film has high contrast and fast response time.

[0107] Example 3

[0108] The synthesis and molecular structure of the conjugated polymers used are shown below:

[0109] The synthesis process of this polymer is as follows:

[0110]

[0111] FN (0.634 g, 1 eq.) and P2NP (0.522 g, 1 eq.) were added to a 5 mL THF solution containing neopentanoic acid (30 mg, 0.3 eq.) and cesium carbonate (0.812 g, 2.5 eq.). Finally, ligand P(o-MeOPh)3 (10 mg, 0.03 eq.) and catalyst Pd(dba)3 were added. . CHCl3 (30 mg, 0.03 eq.) was reacted at 80 °C for 24 hours. After the reaction, the solution was poured into 200 ml of methanol, filtered, and the filter cake was dried. Extraction was performed sequentially with methanol, acetone, hexane, and chloroform. The polymer dissolved in chloroform was collected and evaporated to dryness. The polymer GPC test results were obtained (Mn = 7.5 kDa, D = 2.35).

[0112] Preparation of polymer films:

[0113] The polymer was dissolved in methanol (containing 5% acetic acid by volume) and sprayed onto an ITO substrate to form a film. The solution concentration was 5 mg / ml, and the solution volume was 0.5 ml for each spraying.

[0114] Electrochromic properties of the obtained polymer film: Colorimetric measurements were performed on the polymer film at 0V neutral and 1.1V oxidized states. The results were: neutral state L* = 71.57, a* = 40.08, b* = 42.42; oxidized state L* = 76.92, a* = -4.42, b* = 6.01. Using an electrochemical workstation coupled with a UV-Vis spectrophotometer, the UV-Vis absorption of the prepared film at different voltages was measured in 0.1M tetrabutylammonium hexafluorophosphate / acetonitrile solution. The transmittance at specific wavelengths was also measured in relation to time. The data processing results are as follows: Figure 6 and 7 As shown. From Figure 6 Colorimetric testing shows that the polymer film is orange-red in a neutral state at 0V, and exhibits high transmittance after oxidation at 1.1V. From... Figure 7 It can be seen that the contrast ratio of the film at 490 nm is 52%, and the coloring time and fading time are 1.9 s and 0.6 s, respectively. The test results show that this polymer film has high contrast and fast response time.

[0115] Example 4

[0116] The synthesis and molecular structure of the conjugated polymers used are shown below:

[0117]

[0118] The synthesis process of this polymer is as follows:

[0119] ThN-2Br (0.584 g, 1 eq.) and PBTP (0.500 g, 1 eq.) were added to 5 ml of THF solution containing neopentanoic acid (30 mg, 0.3 eq.) and cesium carbonate (0.812 g, 2.5 eq.). Finally, ligand P(o-MeOPh)3 (10 mg, 0.03 eq.) and catalyst Pd(dba)3 were added. . CHCl3 (30 mg, 0.03 eq.) was reacted at 80 °C for 24 hours. After the reaction, the solution was poured into 200 ml of methanol, filtered, and the filter cake was dried. Extraction was performed sequentially with methanol, acetone, hexane, and chloroform. The polymer dissolved in chloroform was collected and evaporated to dryness. The polymer GPC test results were obtained (Mn = 2.1 kDa, D = 1.50).

[0120] Preparation of polymer films:

[0121] The polymer was dissolved in methanol (containing 5% acetic acid by volume) and sprayed onto an ITO substrate to form a film. The solution concentration was 5 mg / ml, and the solution volume was 0.5 ml for each spraying.

[0122] Electrochromic properties of the obtained polymer film: Colorimetric tests were performed on the polymer film at -0.4V neutral state and 0.8V oxidized state. The results were: neutral state L* = 64.55, a* = -34.12, b* = 8.25; oxidized state L* = 77.81, a* = -2.62, b* = -9.69. Using an electrochemical workstation coupled with a UV-Vis spectrophotometer, the UV-Vis absorption of the prepared film at different voltages was measured in a 0.1M tetrabutylammonium hexafluorophosphate / acetonitrile solution. The transmittance at specific wavelengths was also measured in relation to time. The data processing results are as follows: Figure 8 and 9 As shown. From Figure 8 Colorimetric tests show that the polymer film is green in a neutral state at -0.4V, and exhibits high transmittance after oxidation at 0.8V. From... Figure 9 It can be seen that the contrast ratio of the film at 683nm is 45.4%, and the coloring time and fading time are 1.8s and 1.6s, respectively. The test results show that this polymer film has high contrast and fast response time.

[0123] Example 5

[0124] The synthesis and molecular structure of the conjugated polymers used are shown below:

[0125]

[0126] The synthesis process of this polymer is as follows:

[0127] ThN (0.584 g, 1 eq.) and BTP (0.476 g, 1 eq.) were added to 5 ml of THF solution containing neopentanoic acid (30 mg, 0.3 eq.) and cesium carbonate (0.812 g, 2.5 eq.). Finally, ligand P(o-MeOPh)3 (10 mg, 0.03 eq.) and catalyst Pd(dba)3 were added. . CHCl3 (30 mg, 0.03 eq.) was reacted at 80 °C for 24 hours. After the reaction, the solution was poured into 200 ml of methanol, filtered, and the filter cake was dried. Extraction was performed sequentially with methanol, acetone, hexane, and chloroform. The polymer dissolved in chloroform was collected and evaporated to dryness. The polymer GPC test results were obtained (Mn = 1.9 kDa, D = 1.61).

[0128] Preparation of polymer films:

[0129] The polymer was dissolved in methanol (containing 5% acetic acid by volume) and sprayed onto an ITO substrate to form a film. The solution concentration was 5 mg / ml, and the solution volume was 0.5 ml for each spraying.

[0130] Electrochromic properties of the obtained polymer film: Colorimetric tests were performed on the polymer film at -0.4V neutral state and 0.8V oxidized state. The results were: neutral state L* = 62.08, a* = -34.37, b* = -28.47; oxidized state L* = 90.37, a* = -3.41, b* = -9.6. Using an electrochemical workstation coupled with a UV-Vis spectrophotometer, the UV-Vis absorption of the prepared film at different voltages, the transmittance at specific wavelengths versus time, and the film stability under step voltage were measured in a 0.1M tetrabutylammonium hexafluorophosphate / acetonitrile solution. The data processing results are as follows: Figure 10 and 11 As shown. From Figure 10 Colorimetric tests show that the polymer film is cyan in a neutral state at -0.2V, and exhibits high transmittance after oxidation at 0.9V. From... Figure 11 It can be seen that the contrast ratio of the film at 660 nm is 34.3%, and the coloring time and fading time are 4.5 s and 0.5 s, respectively. The test results show that this polymer film has high contrast and fast response time.

Claims

1. An electrochromic polymer, characterized in that... The polymer is the polymer shown in formula (I): （I） Where: a1 is 0 or 1; m1 is an integer from 3 to 14; The X is one of the following groups: The number-average molecular weight of the electrochromic polymer is Mn = 2000~200000.

2. The method for preparing the electrochromic polymer as described in claim 1, characterized in that... The preparation method is as follows: Monomer 1, Monomer 2, organic acid, inorganic weak base, ligand and palladium catalyst shown in Formula 1 are added to an organic solvent and reacted at 60-100℃ for 6-72h. The resulting reaction mixture is post-treated to obtain the electrochromic polymer shown in Formula (I). 1 （I） The monomer 2 is one of the following compounds: In Formula 1 and Formula (I), a1 is 0 or 1, and m1 is an integer from 3 to 14; in Formula (I), X is one of the following groups: The organic acid is one or a mixture of two of neopentanoic acid and 1-adamantanecarboxylic acid; the inorganic weak base is one or a mixture of more than two of potassium carbonate, sodium carbonate, potassium bicarbonate, and sodium bicarbonate; the ligand is one or a mixture of two of tricyclohexylphosphine fluoroborate and tris(2-methoxyphenyl)phosphine; the palladium catalyst is one or a mixture of more than two of tris(dibenzylacetone)dipalladium(O)-chloroform adduct, palladium acetate, and dichlorodi(triphenylphosphine)palladium; the molar ratio of monomer 1, monomer 2, organic acid, inorganic weak base, ligand, and palladium catalyst shown in Formula 1 is 1:1:0.3~0.5:2~3:0.03~0.1:0.03~0.

1.

3. The method for preparing the electrochromic polymer as described in claim 2, characterized in that: The organic solvent is one or a mixture of two or more of tetrahydrofuran, N-methylpyrrolidone, dimethylformamide, and dimethylacetamide; the volume of the organic solvent is 1 to 20 L / mol based on the total amount of monomer 1 and monomer 2 shown in Formula 1. The post-processing is as follows: the reaction mixture is poured into methanol, filtered, the filter cake is dried, and extracted sequentially with methanol, acetone, hexane and chloroform. The polymer dissolved in chloroform is collected, evaporated to dryness, and the electrochromic polymer shown in formula (I) is obtained.

4. The application of the electrochromic polymer as described in claim 1 in the preparation of electrochromic polymer films.

5. The application as described in claim 4, characterized in that... The application involves dissolving the electrochromic polymer in a solvent to obtain a polymer solution, and then coating the polymer solution onto a conductive substrate to obtain the electrochromic polymer film. The solvent is a methanol solution of acetic acid with a volume fraction of 3-20%, an ethanol solution of acetic acid with a volume fraction of 3-20%, or an aqueous solution of acetic acid with a volume fraction of 3-20%. The concentration of the electrochromic polymer in the polymer solution is 3-10 mg / mL.

6. The application as described in claim 5, characterized in that: The conductive substrate is ITO glass, FTO glass, ITO-PET substrate or FTO-PET substrate.

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