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CN-122011449-A - Preparation method and application of conjugated polymer film based on acid-cleavable side chain

CN122011449ACN 122011449 ACN122011449 ACN 122011449ACN-122011449-A

Abstract

The invention relates to a preparation method and application of a conjugated polymer film based on an acid-cleavable side chain. The preparation method comprises the steps of dissolving a conjugated polymer based on acid cleavable side chains in a solvent to prepare a polymer solution, stirring the polymer solution and a first acid solution uniformly to prepare an acid solution pre-processed polymer/acid mixed solution, coating the acid solution pre-processed polymer/acid mixed solution on a substrate, volatilizing the solvent to form a polymer film, performing first thermal annealing on the polymer film, applying a second acid solution on the surface of the polymer film after the first thermal annealing, and performing second thermal annealing to obtain the acid solution reprocessed conjugated polymer film without side chains. By utilizing the acid sensitivity characteristic of the side chains, partial side chains are removed in advance by adding an acid solution into a polymer solution before the polymer film is formed so as to cooperatively induce the ordering of the polymer, thereby improving the film forming quality and the comprehensive performance of the polymer.

Inventors

  • LI HUI
  • XU YU
  • ZHONG FEI
  • CHEN LIDONG

Assignees

  • 中国科学院上海硅酸盐研究所

Dates

Publication Date
20260512
Application Date
20260206

Claims (10)

  1. 1. A method for preparing a conjugated polymer film based on acid cleavable side chains, comprising the steps of: Step (1) preparing a polymer solution by dissolving a conjugated polymer based on acid cleavable side chains in a solvent; Step (2) stirring the polymer solution and the first acidic solution uniformly to prepare a polymer/acid mixed solution for acid liquor pretreatment; Step (3), coating the polymer/acid mixed solution preprocessed by the acid liquor on a substrate, and forming a polymer film after the solvent volatilizes; step (4) subjecting the polymer film to a first thermal anneal; and (5) applying a second acidic solution to the surface of the polymer film after the first thermal annealing, and then performing the second thermal annealing to obtain the side-chain-free conjugated polymer film reprocessed by acid liquor.
  2. 2. The method according to claim 1, wherein in the step (1), the conjugated main chain of the conjugated polymer based on an acid-cleavable side chain is selected from a conjugated structure based on thiophene, thiazole, pyridine, pyrrolopyrroldiketone, benzothiadiazole, benzobisthiadiazole, aromatic imide, or a derivative thereof, and the side chain of the conjugated polymer based on an acid-cleavable side chain is selected from at least one of a silane side chain, an alkoxy side chain, a carbonyl side chain, an ester side chain, and an imino side chain.
  3. 3. The method according to claim 1 or 2, wherein in the step (2), the acidic solute of the first acidic solution is at least one of an organic acid or an inorganic acid having an acidity coefficient of-2 or more and 5 or less, preferably trichloroacetic acid, acetic acid, trifluoroacetic acid, citric acid, oxalic acid, benzoic acid, phosphoric acid, oxalic acid, and ethylenediamine tetraacetic acid.
  4. 4. A method according to any one of claims 1 to 3, wherein in step (2), the molar ratio of the acidic solute of the first acidic solution to the conjugated polymer repeating unit in the polymer/acid mixed solution is 0.1:1 to 50:1.
  5. 5. The method according to any one of claims 1 to 4, wherein in the step (3), the polymer/acid mixed solution prepared by acid solution is applied by spin coating, drop coating, spray coating, or a heat assisted rapid film forming method, preferably, the heat assisted rapid film forming method comprises the steps of preheating a heating table, placing a substrate on the heating table, applying the polymer/acid mixed solution prepared by acid solution and spreading the solution on the surface of the substrate, and evaporating the solvent to obtain the polymer film.
  6. 6. The method according to any one of claims 1 to 5, wherein in the step (4), the atmosphere of the first thermal annealing is anhydrous and oxygen-free, the temperature of the first thermal annealing is 120 to 300 ℃, and the time of the first thermal annealing is 0.1 to 24 hours.
  7. 7. The method according to any one of claims 1 to 6, wherein in the step (5), the acidic solute of the second acidic solution is at least one selected from the group consisting of hydrochloric acid, sulfuric acid, acetic acid, trichloroacetic acid, p-toluenesulfonic acid, hydrobromic acid, hydrofluoric acid, and trifluoromethanesulfonic acid.
  8. 8. The method according to any one of claims 1 to 7, wherein in the step (5), the temperature of the second thermal annealing is 100 to 170 ℃, and the time of the second thermal annealing is 0.1 to 0.5h.
  9. 9. The method according to any one of claims 1 to 8, wherein the solvent of the first acidic solution and the second acidic solution is independently selected from at least one of methanol, acetonitrile, acetone, chloroform, dichloromethane, ethyl acetate, n-hexane, benzene, chlorobenzene, o-dichlorobenzene, tetrahydrofuran.
  10. 10. Use of a film of an acid-cleavable side chain based conjugated polymer obtained according to the film preparation method according to any one of claims 1 to 9 in thermoelectric devices, heat conducting devices, heat dissipating devices.

Description

Preparation method and application of conjugated polymer film based on acid-cleavable side chain Technical Field The invention belongs to the field of polymer materials, and relates to a preparation method and application of a conjugated polymer film based on an acid-cleavable side chain. Background The conjugated polymer has important application value in the fields of thermoelectric conversion, organic semiconductors, flexible electronic devices and the like by virtue of solution processability, structural adjustability and unique electrical properties. The conjugated polymer solution processing technology has strict requirements on solubility, and the solubility of the material in an organic solvent can be remarkably improved by introducing solubility regulating groups such as alkyl chains, ester groups or alkoxy groups and the like into a conjugated main chain. However, sp 3 hybridized alkyl side chains have high conformational freedom, tend to destroy the backbone planarity, resulting in reduced intermolecular pi-pi stacking order, leading to reduced performance and inadequate thermal stability. For this reason, methods of using functionalized side chains and improving by post-treatment have been widely studied. For example, the introduction of a thermally cleavable ester side chain, an acid cleavable silane side chain, a hydrolytically cleavable t-butoxycarbonyl side chain enables the material to maintain excellent solubility during the solution processing stage, and the partial or complete removal of the side chain is achieved by a controlled chemical or thermal trigger reaction after film formation to enhance the overall properties of the material. In acid cleavable side chain designs, silane or ester based side chains have significant advantages because they are easily cleavable under acidic conditions and the process is simple. However, some of the atoms in these side chains (e.g., silicon atoms in the silane side chains, oxygen atoms in the ester side chains) tend to introduce large steric hindrance, with some difficulty in synthesis. Meanwhile, the molecular weight of the polymer is generally low, although the solution processability advantage is remarkable, the short molecular chain leads to limited charge transmission and dense grain boundary defects in the solid film, and the requirement of preparing a high-performance device is difficult to meet. And too short molecular chains exhibit overactive brownian motion in thermal fields, impeding ordered alignment. This contradiction is particularly prominent in silane substitution systems, and the steric hindrance of the bulky side chains and the insufficient chain length of low molecular weight form double constraints, which lead to poor surface morphology, disordered molecular stacking of the film, and severely limited mobility and domain size. If the relatively active movement of the short molecular chains in the solution state can be effectively inhibited, the film forming quality and microstructure of the polymer film can be improved. Thus, for polymers based on acid cleavable side chains, there is an urgent need to find a versatile method to produce continuous and uniform films. Disclosure of Invention In view of the above problems of the conjugated polymer based on acid cleavable side chains, the present invention proposes a method for preparing a film of the conjugated polymer based on acid cleavable side chains, which uses the acid sensitivity of the side chains to pretreat the polymer solution by acid liquor pretreatment to pre-remove part of the side chains to synergistically induce the ordering of the polymer before the polymer is formed into a film, then, after preparing a continuous and uniform film, reprocessing and annealing the acid solution to completely remove the side chains, thereby obtaining a polymer film without side chains. In a first aspect, the method of preparing a conjugated polymer film based on acid cleavable side chains of the present invention comprises the steps of: Step (1) preparing a polymer solution by dissolving a conjugated polymer based on acid cleavable side chains in a solvent; Step (2) stirring the polymer solution and the first acidic solution uniformly to prepare a polymer/acid mixed solution for acid liquor pretreatment; Step (3), coating the polymer/acid mixed solution preprocessed by the acid liquor on a substrate, and forming a polymer film after the solvent volatilizes; step (4) subjecting the polymer film to a first thermal anneal; And (5) applying a second acidic solution to the surface of the polymer film after the first thermal annealing, and then performing the second thermal annealing to obtain the polymer film without side chains which is reprocessed by acid liquor. In an alternative embodiment, in step (1), the conjugated backbone of the conjugated polymer based on acid cleavable side chains is selected from thiophene, thiazole, pyridine, pyrrolopyrrole dione, benzothiadiazole, benzobisthia