CN111303387B - A kind of electrochromic polymer and its preparation and electrochromic polymer film - Google Patents

Abstract

The invention discloses an electrochromic polymer and a preparation method thereof and an electrochromic polymer film. The structure of the polymer is shown as a formula (I), a formula (II) or a formula (III):

wherein: y is an alkane chain of C10-C50; d is an electron-pushing group; a is an electron withdrawing group; the D is selected from one of the following groups:

the A is selected from one of the following groups:

Description

A kind of electrochromic polymer and its preparation and electrochromic polymer film

(1) Technical field

The present invention relates to an electrochromic polymer, its preparation and a thin film made from the electrochromic polymer.

(2) Background technology

"Electrochromism" (Electrochromism, EC) refers to the phenomenon of stable and reversible changes in the optical properties of materials, such as transmittance, reflectivity, absorptivity, etc. .

Electrochromic materials are mainly divided into inorganic electrochromic materials, organic small molecule electrochromic materials and polymer electrochromic materials. Among them, polymer electrochromic materials (PEC) have huge applications in the fields of smart windows, flat-panel displays, information labels, etc. value, has been extensively studied. According to different polymerization methods, PEC materials can generally be divided into electrochemically polymerized PEC materials and chemically polymerized PEC materials. Chemically polymerized PEC materials usually have good solution processing properties, and thin films can be prepared by spray coating, spin coating, ink printing, screen printing and other techniques, so that large-area and low-cost preparation of PEC devices can be realized. Therefore, it has attracted much attention.

In the past decade, solution-processed PEC materials have been developed rapidly, and various solution-processed PEC materials have been designed and synthesized. However, at present, most of the technical patents of solution-processed PEC materials with good application prospects are concentrated in developed countries such as Europe and the United States, and domestic technical patents with independent intellectual property rights in this field are relatively scarce. Therefore, it is necessary to develop new solution-processable PEC materials with high performance and industrial application prospects.

(3) Contents of the invention

The first object of the present invention is to provide an electrochromic polymer, which can achieve a stable and reversible transition from neutral state coloring to oxidized state high transmission under the action of an electric field, and has good solubility in organic solvents .

A second object of the present invention is to provide a method for the preparation of electrochromic polymers.

A third object of the present invention is to provide an electrochromic polymer film.

The object of the present invention is achieved through the following technical solutions:

In a first aspect, the present invention provides an electrochromic polymer, and the polymer is one of the following structures:

In the formula: Y is an alkane chain of C10-C50; D is an electron-pushing group; A is an electron-withdrawing group;

The D is selected from one of the following groups:

The A is selected from one of the following groups:

Wherein, R is H or C1-C50 alkane chain or alkoxy chain; Z is S or Se; X is H or C1-C50 alkane chain or alkoxy chain;

The number-average molecular weight Mn of the electrochromic polymer is 5000-200000, and the polydispersity coefficient D is 1.0-5.0.

Preferably, R is a C5-C20 alkoxy group.

Preferably, the number average molecular weight Mn of the electrochromic polymer is 10000-50000.

In a second aspect, the present invention provides a method for preparing an electrochromic polymer represented by formula (I), which is prepared by polycondensation of monomer 1 and monomer 2 or monomer 3 through arylation;

In formula 1 or 2 or 3, the definitions of Y, R and Z are the same as formula (I).

The preparation method of the polymer shown in formula (I) is specifically: adding monomer 1 and monomer 2 or monomer 3 to an organic solvent containing organic acid, inorganic weak base and palladium catalyst for reaction, after the reaction , obtain the electrochromic polymer shown in formula (I) through aftertreatment.

Preferably, the organic acid is one or both of pivalic acid and 1-adamantanecarboxylic acid.

Preferably, the weak inorganic base is one or a combination of at least two of potassium carbonate, sodium carbonate, potassium bicarbonate and sodium bicarbonate.

Preferably, the palladium catalyst is one or both of palladium acetate and dichlorobis(triphenylphosphine)palladium.

Preferably, the organic solvent is one or a combination of at least two of N-methylpyrrolidone, dimethylformamide, and dimethylacetamide.

Preferably, the molar ratio of monomer 1 to monomer 2, organic acid, inorganic weak base, and palladium catalyst is 1:1:0.3-0.5:2-3:3-10%.

Preferably, the reaction temperature of the polymerization reaction is 100-160°C, more preferably 120-140°C.

Preferably, the reaction time of the polymerization reaction is 6-72 hours, more preferably 12-36 hours.

As a preference, the post-treatment can adopt the following steps: pour the reaction mixture into methanol, filter, dry, extract with methanol, acetone, hexane, and chloroform successively, and collect the polymer dissolved in chloroform , spin dry.

In a third aspect, the present invention provides a method for preparing an electrochromic polymer represented by formula (II), comprising the steps of:

(1) adding compound 1 and compound 6 or compound 7 to an organic solvent containing a palladium catalyst for reaction, after the reaction is completed, monomer 4 or monomer 5 is obtained through post-treatment;

(2) Monomer 4 or monomer 5 is oxidatively polymerized by ferric chloride to prepare the electrochromic polymer shown in formula (II);

In formula 1, 6, 7, 4 or 5, the definitions of R, Y and Z are the same as in formula (II).

Preferably, in step (1), the molar ratio of compound 1 to compound 6 or 7 is 1:2-4.

Preferably, in step (1), the palladium catalyst is one or both of tetrakis(triphenylphosphine)palladium and dichlorobis(triphenylphosphine)palladium.

Preferably, in step (1), the molar ratio of the compound 6 or 7 to the palladium catalyst is 1:3-10%.

Preferably, in step (1), the organic solvent is one or a combination of at least two of tetrahydrofuran and toluene.

Preferably, in step (1), the reaction temperature is 65-110° C., and the reaction time is 12-36 hours.

Preferably, in step (1), the post-treatment is: after the reaction, extract with water and dichloromethane, combine the organic layers, dry, and separate by column chromatography to obtain monomer 4 or monomer 5.

The step (2) is specifically implemented as follows: monomer 4 or monomer 5 is added to a solvent containing ferric chloride, and after the reaction is completed, the electrochromic polymer shown in formula (II) is obtained through post-treatment .

Preferably, in step (2), the molar ratio of monomer 4 or monomer 5 to ferric chloride in the polymerization reaction is 1:1-8.

As a preference, in step (2), the solvent used in the polymerization reaction is one or both of dichloromethane, chloroform and tetrahydrofuran.

Preferably, in step (2), the polymerization reaction temperature is 20-30° C., and the polymerization reaction time is 12-36 hours.

As a preference, in step (2), the post-treatment can adopt the following steps: pour the reaction mixture into methanol, filter, dry, extract with methanol, acetone, hexane, and chloroform successively, and collect the trichloro Polymer dissolved in methane, spin-dried.

In a fourth aspect, the present invention provides a method for preparing an electrochromic polymer represented by formula (III), comprising the following steps:

(A) adding compound 1 and compound 6 or compound 7 to an organic solvent containing a palladium catalyst for reaction, after the reaction is completed, monomer 4 or monomer 5 is obtained through post-treatment;

(B) Monomer 4 or Monomer 5 and Monomer 8 or Monomer 9 or Monomer 10 or Monomer 11 are arylated and polycondensed to prepare the electrochromic polymer shown in formula (III);

In formula 1 or 6 or 7 or 4 or 5 or 10 or 11, the definitions of R, Y, X and Z are the same as formula (III).

The implementation of the step (A) is the same as that of the above step (1), and will not be repeated here.

The step (B) is specifically implemented as follows: monomer 4 or monomer 5 and monomer 8 or monomer 9 or monomer 10 or monomer 11 are added to the organic acid containing organic acid and inorganic weak base and palladium catalyst. In the solvent, after the reaction is finished, the polymer represented by the formula (III) is obtained through aftertreatment.

Preferably, in step (B), the organic acid is one or both of pivalic acid and 1-adamantanecarboxylic acid.

Preferably, in step (B), the weak inorganic base is one or a combination of at least two of potassium carbonate, sodium carbonate, potassium bicarbonate and sodium bicarbonate.

Preferably, in step (B), the palladium catalyst is one or both of palladium acetate and dichlorobis(triphenylphosphine)palladium.

Preferably, in step (B), the organic solvent is one or a combination of at least two of N-methylpyrrolidone, dimethylformamide, and dimethylacetamide.

As a preference, in step (B), the molar ratio of monomer 4 or monomer 5 to monomer 8 or monomer 9 or monomer 10 or monomer 11 to organic acid, inorganic weak base and catalyst is 1:1: 0.3-0.5: 2-3: 3-10%.

Preferably, in step (B), the reaction temperature of the polymerization reaction is 100-160°C, more preferably 120-140°C.

Preferably, in step (B), the reaction time of the polymerization reaction is 6-72 hours, more preferably 12-36 hours.

As a preference, in step (B), the post-treatment can adopt the following steps: pour the reaction mixture into methanol, filter, dry, extract with methanol, acetone, hexane, and chloroform successively, and collect the trichloro Polymer dissolved in methane, spin-dried.

Monomer 1, monomer 2, monomer 3, monomer 6, monomer 7, monomer 8, monomer 9, monomer 10 and monomer 11 used in the present invention can be carried out according to or with reference to the methods reported in existing literature For synthesis, for example, monomer 1 can be synthesized by referring to [Adv.Funct.Mater.2018, 28, 1804512].

In the fifth aspect, the present invention provides an electrochromic polymer film, which is made of the electrochromic polymer.

Preferably, the electrochromic polymer film is obtained by processing the electrochromic polymer into a film through solution.

As a further preference, the processing of the solution into a film specifically comprises: dissolving the electrochromic polymer in a solvent to obtain a solution, and then coating the solution on a conductive substrate to obtain an electrochromic polymer film. More preferably, the solvent is dichloromethane, chloroform, tetrahydrofuran, toluene, dimethylformamide.

In the present invention, the coating method may be spray coating, spin coating, screen printing and the like. The conductive substrate may be ITO glass, FTO glass, ITO-PET substrate, FTO-PET substrate and the like.

The electrochromic polymer film obtained by the invention has potential application value in the fields of smart windows, displays, protective glasses and the like.

Compared with the prior art, the present invention has the following advantages and beneficial effects:

(1) The polymer involved in the present invention has good solubility in common organic solvents, and the large-area preparation of its film material can be realized by solution processing.

(2) The polymer film prepared by the present invention can achieve a stable and reversible transition from neutral state coloring to oxidized state high transmission at low voltage (about 1.0V), and has potential applications in the fields of displays, smart windows, mobile phone cases, etc. value.

(4) Description of drawings

Fig. 1: the optical absorption of the prepared polymer film in embodiment 1 under different voltages;

Figures 2 and 3: The curves of the transmittance of the polymer film prepared in Example 1 as a function of time under multiple potential steps from 0 to 1.1V at specific wavelengths;

Fig. 4: the optical absorption of the polymer film prepared in embodiment 2 under different voltages;

Figures 5 and 6: The curves of the transmittance of the polymer film prepared in Example 2 as a function of time under multiple potential steps from 0 to 1.0V at specific wavelengths;

Fig. 7: the optical absorption of the polymer film prepared in embodiment 3 under different voltages;

Figures 8 and 9: The curves of 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 specific wavelengths;

(5) Specific implementation methods

The technical solutions of the present invention will be further described below with specific examples, but the protection scope of the present invention is not limited thereto.

Example 1

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

The synthesis process of this polymer is as follows:

Br-PC-Br (0.73g, 1eq.) and P (0.44g, 1eq.) were added to 20ml of DMAc solution containing pivalic acid (30mg, 0.3eq.) and potassium carbonate (345mg, 2.5eq.), Finally, Pd(OAc) ₂ (7mg, 0.03eq.) catalyst was added and reacted at 120°C for 24 hours. After the reaction, the solution was poured into methanol, filtered, dried, extracted with methanol, acetone, hexane, and chloroform in sequence, and the polymer dissolved in chloroform was collected and spin-dried. Polymer GPC test results (Mn=14.9KDa, D=2.68).

Preparation of polymer films:

The polymer was dissolved in chloroform and spin-coated on the ITO substrate to form a film, the solution concentration was 18 mg/ml, the rotational speed was 1000 r/min, and the time was 1 min.

The electrochromic performance test of the obtained polymer film: the chromaticity test is carried out to the polymer film under the neutral state of 0V and the oxidation state of 1.1V, and the results are neutral state L*=85.05, a*=15.16, b*=33.02 , oxidation state L*=90.01, a*=-0.82, b*=6.70. Using an electrochemical workstation combined with a UV-Vis spectrophotometer, in a 0.1M lithium perchlorate/propylene carbonate solution, test the UV-Vis absorption of the prepared film at different voltages, and the absorption at a specific wavelength The relationship between transmittance and time and the film stability test under step voltage, the data processing results are shown in Figures 1, 2 and 3. From Figure 1 and the chromaticity test, it can be seen that the polymer film is orange-yellow in the neutral state of 0V, and the polymer film is in a high transmission state after oxidation at a voltage of 1.1V. It can be seen from Figure 2 that the contrast of the film at 479nm is 40%. From the film stability test (5s step time) in Figure 3, it can be seen that after 1000 cycles, the contrast ratio remains 86%.

Example 2

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

The synthesis process of this polymer is as follows:

Add P (3.65, 1eq.) to 40ml THF solution containing Br-PC-Br (1.76g, 0.5eq.), add Pd(PPh ₃ ) ₂ Cl ₂ (105mg, 0.03eq.), and react under reflux After 15 hours, after the reaction was completed, it was extracted with water and dichloromethane, dried, and separated by column chromatography to obtain PPCP.

The H NMR spectrum characterization data of PPCP are as follows:

PPCP: ¹ H NMR (400MHz, CDCl ₃ ), δ(ppm): 8.70, 8.16, 7.83 (CH of benzene ring), 6.63 (CH of thiophene ring), 4.56 (N-CH2-), 4.17, 3.51, 3.30 (- CH2-O), 0.8-1.5 (alkyl side chain hydrogen).

PPCP (1.42g, 1eq.) was added to 20ml of chloroform containing ferric chloride (0.64g, 4eq.), and reacted at 30°C for 24 hours. After the reaction, the solution was poured into methanol and filtered. Dry it, extract it with methanol, acetone, hexane, and chloroform in sequence, collect the polymer dissolved in chloroform, and spin dry. Polymer GPC test results (Mn=23.1KDa, D=3.46).

Preparation of polymer films:

The polymer was dissolved in chloroform and spin-coated on the ITO substrate to form a film. The concentration of the solution was 12 mg/ml, the rotation speed was 1500 r/min, and the time was 1 min.

The electrochromic performance test of the obtained polymer film: the chromaticity test is carried out to the polymer film under the neutral state of 0V and the oxidation state of 1.0V, and the results are neutral state L*=79.82, a*=31.24, b*=30.34 , oxidation state L*=85.08, a*=-4.73, b*=14.83. Using an electrochemical workstation combined with a UV-Vis spectrophotometer, in a 0.1M lithium perchlorate/propylene carbonate solution, test the UV-Vis absorption of the prepared film at different voltages, and the absorption at a specific wavelength The relationship between transmittance and time and the film stability test under step voltage, the data processing results are shown in Figures 4, 5 and 6. From Figure 4 and the chromaticity test, it can be seen that the polymer film is orange-red in the neutral state of 0V, and the polymer film is in a high transmission state after oxidation at a voltage of 1.0V. It can be seen from Figure 5 that the contrast ratio of the film at 497nm is 54%. From the film stability test (0V5s+1V10s step time) in Figure 6, it can be seen that after 1000 cycles, the contrast remains 97%.

Example 3

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

The synthesis process of this polymer is as follows:

PPCP (1.42g, 1eq.) and Br-BT-Br (0.29g, 1eq.) were added to a 20ml DMAc solution containing pivalic acid (30mg, 0.3eq.) and potassium carbonate (0.34g, 2.5eq.) , and finally add Pd(OAc) ₂ (7mg, 0.03eq.) catalyst and react at 120°C for 24 hours. After the reaction, the solution was poured into methanol, filtered, dried, extracted with methanol, acetone, hexane, and chloroform in sequence, and the polymer dissolved in chloroform was collected and spin-dried. Polymer GPC test results (Mn=19.0KDa, D=3.36).

Preparation of polymer films:

The polymer was dissolved in chloroform and spin-coated on the ITO substrate to form a film. The concentration of the solution was 18 mg/ml, the rotation speed was 1000 r/min, and the time was 1 min.

The electrochromic performance test of the obtained polymer film: the chromaticity test is carried out to the polymer film under the neutral state of 0V and the oxidation state of 1.1V, and the results are neutral state L*=75.23, a*=16.85, b*=6.74 , oxidation state L*=82.20, a*=3.54, b*=2.02. Using an electrochemical workstation combined with a UV-Vis spectrophotometer, in a 0.1M lithium perchlorate/propylene carbonate solution, test the UV-Vis absorption of the prepared film at different voltages, and the absorption at a specific wavelength The relationship between transmittance and time and the film stability test under step voltage, the data processing results are shown in Figures 7, 8 and 9. From Figure 7 and the chromaticity test, it can be seen that the polymer film is deep red in the neutral state of 0V, and the polymer film is in a high transmittance state after oxidation at a voltage of 1.1V. It can be seen from Figure 8 that the contrast ratio of the film at 489 nm is 39%. From the film stability test (0V5s+1V10s step time) in Figure 9, it can be seen that after 1000 cycles, the contrast remains 78%.

Claims (9)

1. An electrochromic polymer having a structure represented by formula (I) or (II) or (III):

wherein: y is an alkane chain of C10-C50; d is an electron-pushing group; a is an electron withdrawing group;

the D is selected from the following groups:

the A is selected from one of the following groups:

wherein R is an alkoxy group of C5-C15; z is S or Se; x is H or an alkane chain or an alkoxy chain of C1-C50;

the electrochromic polymer has a number average molecular weight Mn=5000-200000 and a polydispersity D=1.0-5.0.

2. The electrochromic polymer of claim 1, wherein: the electrochromic polymer has a number average molecular weight mn=10000-50000.

3. A process for the preparation of electrochromic polymers of formula (I), characterized in that: the electrochromic polymer is prepared by arylating and polycondensing a monomer 1 and a monomer 2;

in formula 1 or 2 or (I): y is an alkane chain of C10-C50; d is an electron-donating group, and D is selected from the following groups:

wherein R is H or an alkane chain or an alkoxy chain of C1-C50; z is S or Se;

the electrochromic polymer has a number average molecular weight Mn=5000-200000 and a polydispersity D=1.0-5.0.

4. A method of preparation as claimed in claim 3, wherein: the preparation method of the polymer shown in the formula (I) specifically comprises the following steps: and adding the monomer 1 and the monomer 2 into an organic solvent containing organic acid, inorganic weak base and palladium catalyst to react, and after the reaction is finished, performing post-treatment to obtain the electrochromic polymer shown in the formula (I).

5. A method for preparing an electrochromic polymer represented by formula (II), comprising the steps of:

(1) Adding the compound 1 and the compound 6 into an organic solvent containing a palladium catalyst for reaction, and after the reaction is finished, performing post-treatment to obtain a monomer 4;

(2) The monomer 4 is oxidized and polymerized by ferric trichloride to prepare electrochromic polymer shown in a formula (II);

in formula 1, 6, 4 or (I): y is an alkane chain of C10-C50; d is an electron-donating group, and D is selected from the following groups:

wherein R is H or an alkane chain or an alkoxy chain of C1-C50; z is S or Se;

the electrochromic polymer has a number average molecular weight Mn=5000-200000 and a polydispersity D=1.0-5.0.

6. A method for preparing an electrochromic polymer represented by formula (III), comprising the steps of:

(A) Adding the compound 1 and the compound 6 into an organic solvent containing a palladium catalyst for reaction, and after the reaction is finished, performing post-treatment to obtain a monomer 4;

(B) The electrochromic polymer shown in the formula (III) is prepared by arylating and polycondensing the monomer 4 and the monomer 8 or the monomer 9 or the monomer 10 or the monomer 11;

in formula 1 or 6 or 4 or 10 or 11 or (III): y is an alkane chain of C10-C50; d is an electron-pushing group; a is an electron withdrawing group;

the D is selected from the following groups:

the A is selected from one of the following groups:

wherein R is H or an alkane chain or an alkoxy chain of C1-C50; z is S or Se; x is H or an alkane chain or an alkoxy chain of C1-C50;

the electrochromic polymer has a number average molecular weight Mn=5000-200000 and a polydispersity D=1.0-5.0.

7. The method of manufacturing according to claim 6, wherein: the step (B) is specifically implemented as follows: and adding the monomer 4 and the monomer 8 or the monomer 9 or the monomer 10 or the monomer 11 into an organic solvent containing organic acid and inorganic weak base and palladium catalyst, and after the reaction is finished, performing post-treatment to obtain the polymer shown in the formula (III).

8. An electrochromic polymer film made from the electrochromic polymer of claim 1.

9. The electrochromic polymer film of claim 8, wherein: the electrochromic polymer film is obtained by processing the electrochromic polymer into a film through a solution.

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