CN111303387B

CN111303387B - Electrochromic polymer and preparation thereof, and electrochromic polymer film

Info

Publication number: CN111303387B
Application number: CN202010132583.9A
Authority: CN
Inventors: 李维军; 付海长; 闫拴马; 张�诚
Original assignee: Zhejiang University of Technology ZJUT
Current assignee: Zhejiang University of Technology ZJUT
Priority date: 2020-02-29
Filing date: 2020-02-29
Publication date: 2023-07-11
Anticipated expiration: 2040-02-29
Also published as: CN111303387A

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

Electrochromic polymer and preparation thereof, and electrochromic polymer film

Field of the art

The present invention relates to electrochromic polymers, their preparation and films made from electrochromic polymers.

(II) background art

"electrochromic" (EC) refers to a phenomenon in which optical properties of a material, such as transmittance, reflectance, absorptivity, etc., change steadily and reversibly under the action of an applied electric field, and macroscopically show reversible changes in color and transparency.

Electrochromic materials are mainly classified into inorganic electrochromic materials, organic small molecule electrochromic materials and polymer electrochromic materials. The polymer electrochromic material (PEC) has the characteristics of controllable energy band, good processing performance, excellent electrochromic comprehensive performance and the like because of the easy modification of the structure, and has great application value in the fields of intelligent windows, flat panel displays, information labels and the like, and is widely studied. PEC materials can be generally classified into electrochemically polymerized PEC materials and chemically polymerized PEC materials, depending on the manner of polymerization. Chemically polymerized PEC materials generally have good solution processability and thin films can be prepared by spray, spin, ink, screen, etc. techniques, thus allowing large area, low cost fabrication of PEC devices and, therefore, are of great interest.

In the last decade, solution processed PEC materials have been rapidly developed, and a wide variety of solution processed PEC materials have been designed for synthesis. However, most of the technical patents of solution processing PEC materials with good application prospects are concentrated in developed countries such as europe and america, and the domestic technical patents with independent intellectual property rights in the field are relatively lacking. Therefore, development of a novel solution processable PEC material with high performance and industrial application prospect is necessary.

(III) summary of the invention

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

It is a second object of the present invention to provide a method for preparing electrochromic polymers.

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

The aim of the invention is achieved by the following technical scheme:

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

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:

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.

Preferably, R is a C5-C20 alkoxy group.

Preferably, the electrochromic polymer has a number average molecular weight mn=10000 to 50000.

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

in formula 1 or 2 or 3, Y and R and Z are as defined for formula (I).

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 or the monomer 3 into an organic solvent containing organic acid, inorganic weak base and palladium catalyst for reaction, and after the reaction is finished, performing post-treatment to obtain the electrochromic polymer shown in the formula (I).

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

Preferably, the inorganic weak 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 two of palladium acetate and dichloro bis (triphenylphosphine) palladium.

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

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

Preferably, the reaction temperature of the polymerization reaction is 100 to 160 ℃, more preferably 120 to 140 ℃.

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

Preferably, the post-treatment may be performed by the following steps: pouring the reaction mixture into methanol, filtering, drying, sequentially extracting with methanol, acetone, hexane and chloroform, collecting polymer dissolved in chloroform, and spin-drying.

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 the compound 1 and the compound 6 or the compound 7 into an organic solvent containing a palladium catalyst for reaction, and after the reaction is finished, carrying out aftertreatment to obtain a monomer 4 or a monomer 5;

(2) The monomer 4 or the monomer 5 is oxidized and polymerized by ferric trichloride to prepare an electrochromic polymer shown in a formula (II);

in formula 1, 6, 7, 4 or 5, R and Y and Z are as defined for formula (II).

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

Preferably, in the step (1), the palladium catalyst is one or two of tetra (triphenylphosphine) palladium and dichloro di (triphenylphosphine) palladium.

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

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

Preferably, in the step (1), the reaction temperature is 65-110 ℃ and the reaction time is 12-36 h.

Preferably, in the step (1), the post-treatment is: after the reaction is finished, extracting with water and dichloromethane, combining organic layers, drying, and separating by column chromatography to obtain a monomer 4 or a monomer 5.

The step (2) is specifically implemented as follows: and adding the monomer 4 or the monomer 5 into a solvent containing ferric trichloride, and after the reaction is finished, performing post-treatment to obtain the electrochromic polymer shown in the formula (II).

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

Preferably, in the step (2), the solvent used in the polymerization reaction is one or two of dichloromethane, chloroform and tetrahydrofuran.

Preferably, in the step (2), the polymerization temperature is 20 to 30 ℃ and the polymerization time is 12 to 36 hours.

Preferably, in the step (2), the post-treatment may be performed as follows: pouring the reaction mixture into methanol, filtering, drying, sequentially extracting with methanol, acetone, hexane and chloroform, collecting polymer dissolved in chloroform, and spin-drying.

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

(A) Adding the compound 1 and the compound 6 or the compound 7 into an organic solvent containing a palladium catalyst for reaction, and after the reaction is finished, carrying out aftertreatment to obtain a monomer 4 or a monomer 5;

(B) The electrochromic polymer shown in the formula (III) is prepared by arylation polycondensation of the monomer 4 or the monomer 5 and the monomer 8 or the monomer 9 or the monomer 10 or the monomer 11;

in formula 1 or 6 or 7 or 4 or 5 or 10 or 11, R, Y, X, Z is as defined for formula (III).

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

The step (B) is specifically implemented as follows: adding the monomer 4 or the monomer 5 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, obtaining the polymer shown in the formula (III) through post-treatment.

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

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

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

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

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

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

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

Preferably, in the step (B), the post-treatment may be performed as follows: pouring the reaction mixture into methanol, filtering, drying, sequentially extracting with methanol, acetone, hexane and chloroform, collecting polymer dissolved in chloroform, and spin-drying.

The monomers 1, 2, 3, 6, 7, 8, 9, 10 and 11 used in the present invention may be synthesized according to or by reference to methods reported in the prior art, for example, monomer 1 may be synthesized by reference to [ adv.funct.mater.2018,28,1804512 ].

In a fifth aspect, the present invention provides an electrochromic polymer film made from the electrochromic polymer.

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

As a further preferred, the solution processing film is specifically: and (3) dissolving the electrochromic polymer in a solvent to obtain a solution, and then coating the solution on the conductive substrate to obtain the electrochromic polymer film. More preferably, the solvent is dichloromethane, chloroform, tetrahydrofuran, toluene, dimethylformamide.

In the invention, the coating mode can be spray coating, spin coating, screen printing and the like. The conductive substrate can 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 intelligent windows, displays, protective glasses and the like.

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

(1) The polymer has good solubility in common organic solvents, and can realize large-area preparation of film materials by a solution processing method.

(2) The polymer film prepared by the invention can realize stable and reversible conversion from neutral state coloring to oxidation state high transmission under low voltage (about 1.0V), and has potential application value in the fields of displays, intelligent windows, mobile phone shells and the like.

(IV) description of the drawings

Fig. 1: the polymer film prepared in example 1 has optical absorption at different voltages;

fig. 2, 3: a plot of transmittance over time for the polymer film prepared in example 1 at a specific wavelength from 0 to 1.1V multi-potential step;

fig. 4: the polymer films prepared in example 2 were optically absorbing at different voltages;

fig. 5, 6: a plot of transmittance over time for the polymer film prepared in example 2 at a specific wavelength from 0 to 1.0V multi-potential step;

fig. 7: the polymer films prepared in example 3 were optically absorbing at different voltages;

fig. 8, 9: a plot of transmittance over time for the polymer film prepared in example 3 at a specific wavelength from 0 to 1.1V multi-potential step;

(fifth) detailed description of the invention

The technical scheme of the present invention is further described in the following specific examples, but the scope of the present invention is not limited thereto.

Example 1

The synthesis and molecular structure of the conjugated polymer used are as follows:

the synthesis process of the polymer is as follows:

Br-PC-Br (0.73 g,1 eq.) and P (0.44 g,1 eq.) were added to a 20ml DMAc solution containing pivalic acid (30 mg,0.3 eq.) and potassium carbonate (345 mg,2.5 eq.) and finally Pd (OAc) ₂ (7 mg,0.03 eq.) catalyst, at 120℃for 24 hours. After the reaction is finished, the solution is poured into methanol, filtered and dried, and is sequentially extracted by methanol, acetone, hexane and chloroform, and the polymer dissolved in the chloroform is collected and dried by spin. Polymer GPC test results (mn=14.9 kda, d=2.68).

Preparation of a polymer film:

the polymer is dissolved in chloroform and spin-coated on an ITO substrate to prepare a film, the concentration of the solution is 18mg/ml, the rotating speed is 1000r/min, and the time is 1min.

Electrochromic properties test of the resulting polymer films: the polymer film was colorimetrically tested in the 0V neutral state and in the 1.1V oxidation state, resulting in a neutral state of lx=85.05, a=15.16, b=33.02, oxidation state of lx=90.01, a=0.82, b=6.70. The prepared films were tested for uv-vis absorption at different voltages, transmittance at specific wavelengths versus time, and film stability at step voltages in a 0.1M lithium perchlorate/propylene carbonate solution using an electrochemical workstation and uv-vis spectrophotometer combination device, and the data processing results are shown in figures 1 and 2 and 3. From FIG. 1 and the colorimetric test, it can be seen that the polymer film is orange-yellow in the neutral state of 0V and has a high transmission state after oxidation at a voltage of 1.1V. It can be seen from FIG. 2 that the contrast of the film at 479nm is 40%. From the film stability test of fig. 3 (5 s step time), it can be seen that the contrast remains 86% after 1000 cycles.

Example 2

the synthesis process of the polymer is as follows:

p (3.65, 1 eq.) was added to a solution of Br-PC-Br (1.76 g,0.5 eq.) in 40ml of tetrahydrofuran, pd (PPh) was added ₃ ) ₂ Cl ₂ (105 mg,0.03 eq.) under reflux for 15 hours, extracted with water and dichloromethane after the reaction, dried and separated by column chromatography to give PPCP.

The nuclear magnetic hydrogen spectrum characterization data of PPCP are as follows:

PPCP: ¹ H NMR(400MHz,CDCl ₃ ) Delta (ppm): 8.70, 8.16, 7.83 (benzene ring C-H), 6.63 (thiophene ring C-H), 4.56 (N-CH 2-), 4.17, 3.51, 3.30 (-CH 2-O), 0.8-1.5 (alkyl side chain hydrogen).

PPCP (1.42 g,1 eq.) was added to 20ml of chloroform containing ferric trichloride (0.64 g,4 eq.) and reacted at 30℃for 24 hours, after the reaction was completed, the solution was poured into methanol, filtered, dried, and extracted sequentially with methanol, acetone, hexane, chloroform, and the polymer dissolved in chloroform was collected and dried by spinning. Polymer GPC test results (mn=23.1 kda, d=3.46).

Preparation of a polymer film:

and (3) dissolving the polymer in chloroform, and carrying out spin coating film making on an ITO substrate, wherein the concentration of the solution is 12mg/ml, the rotating speed is 1500r/min, and the time is 1min.

Electrochromic properties test of the resulting polymer films: the polymer films were colorimetrically tested in the 0V neutral state and in the 1.0V oxidation state, resulting in the neutral state lx=79.82, a=31.24, b=30.34, oxidation state lx=85.08, a=4.73, b=14.83. The prepared films were tested for uv-vis absorption at different voltages, transmittance at specific wavelengths versus time, and film stability at step voltages in a 0.1M lithium perchlorate/propylene carbonate solution using an electrochemical workstation and uv-vis spectrophotometer, respectively, and the data processing results are shown in figures 4 and 5 and 6. From fig. 4 and the colorimetric test, it can be seen that the polymer film is orange-red in the neutral state of 0V and is highly transmissive after oxidation at a voltage of 1.0V. From FIG. 5, it can be seen that the contrast of the film at 497nm is 54%. From the film stability test of fig. 6 (0v5s+1v10s step time), it can be seen that after 1000 cycles, the contrast remains 97%.

Example 3

the synthesis process of the polymer is as follows:

PPCP (1.42 g,1 eq.) and Br-BT-Br (0.29 g,1 eq.) were added to a 20ml DMAc solution containing pivalic acid (30 mg,0.3 eq.) and potassium carbonate (0.34 g,2.5 eq.) and finally Pd (OAc) ₂ (7 mg,0.03 eq.) catalyst, at 120℃for 24 hours. After the reaction is finished, the solution is poured into methanol, filtered and dried, and is sequentially extracted by methanol, acetone, hexane and chloroform, and the polymer dissolved in the chloroform is collected and dried by spin. Polymer GPC test results (mn=19.0 kda, d=3.36).

Preparation of a polymer film:

and (3) dissolving the polymer in chloroform, and carrying out spin coating film making on an ITO substrate, wherein the concentration of the solution is 18mg/ml, the rotating speed is 1000r/min, and the time is 1min.

Electrochromic properties test of the resulting polymer films: the polymer films were colorimetrically tested in the 0V neutral state and in the 1.1V oxidation state, resulting in the neutral state l=75.23, a=16.85, b=6.74, oxidation state l=82.20, a=3.54, b=2.02. The prepared films were tested for uv-vis absorption at different voltages, transmittance at specific wavelengths versus time, and film stability at step voltages in a 0.1M lithium perchlorate/propylene carbonate solution using an electrochemical workstation and uv-vis spectrophotometer, respectively, and the data processing results are shown in fig. 7 and 8 and 9. From fig. 7 and the colorimetric test, it can be seen that the polymer film was dark red in the neutral state of 0V and in the high transmission state after oxidation at a voltage of 1.1V. From FIG. 8, it can be seen that the film has a contrast of 39% at 489 nm. From the film stability test of fig. 9 (0v5s+1v10s step time), it can be seen that the contrast ratio remains 78% after 1000 cycles.

Claims

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

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;

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;

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;

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:

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.