Dioxythiophene polymer, composition, chiral film and preparation method thereof

Abstract

The invention discloses a dioxythiophene polymer, a composition, a chiral film and a preparation method thereof. The dioxythiophene polymer has a specific chemical structure. The dioxythiophene polymer and a specific chiral inducer form a composition, the composition is prepared into a film, and the film is annealed to obtain the chiral film with strong circular dichroism signals. According to the present invention, the efficient conversion from the achiral conjugated polymer to the long-range ordered chiral material is achieved through the simple post-doping and annealing process, the method is simple and convenient, the chiral regulation effect is significant, and the important value is provided in the circularly polarized light related application field.

Description

Technical Field

[0001] This invention belongs to the field of functional polymer technology, specifically relating to a dioxothiophene polymer, a composition, a chiral film, and a method for preparing the same. Background Technology

[0002] Conjugated polymers, due to their unique π-electron conjugated system, have shown excellent application potential in fields such as organic optoelectronics, sensing and detection, and biomedicine. Among them, polydioxythiophene conjugated polymers have become a research hotspot due to their good conductivity, environmental stability, and modifiability of molecular structure. As functional materials develop towards higher specificity and refinement, single optoelectronic properties can no longer meet the needs of complex scenarios. Chirality, as a fundamental property universally present in nature, endows conjugated polymers with new functional dimensions. Especially in applications related to circularly polarized light, in the traditional preparation path, unpolarized light needs to pass through the synergistic effect of a wire grating polarizer and a quarter-wave plate to generate circularly polarized light (CPL). However, this process inevitably produces significant brightness attenuation and is prone to defects such as insufficient phase matching. To avoid these problems, researchers have been committed to developing chiral emission materials that can directly generate CPL. The preparation of chiral conjugated polymers typically requires highly sophisticated synthesis techniques. Not only do they necessitate high-purity chiral monomers as the reaction starting point to prevent racemization from affecting the final chiral properties, but they also demand extremely stringent control of reaction conditions, such as precise regulation of temperature, humidity, and reaction time, to ensure the orderly growth of the conjugated backbone. Therefore, the research approach of preparing chiral polydioxythiophene conjugated polymers from achiral polydioxythiophene conjugated polymers using simple chiral inducers is of significant importance. This invention aims to address the aforementioned technical challenges in this field. Summary of the Invention

[0003] To address the aforementioned technical problems, in a first aspect, the present invention provides a dioxothiophene polymer, the structural formula of which is shown below. ; Wherein, R is an alkyl group; m is a positive integer such that the number-average molecular weight of the dioxothiophene polymer is between 5000 and 50000. The dioxothiophene polymer having the above structure and molecular weight possesses a good conjugated system and can be formulated with an appropriate proportion of chiral inducing agent to form a desired chiral emission material. The composite film prepared using this material, after heat annealing, forms the desired chiral emission material.

[0004] Furthermore, the molecular weight distribution of the dioxothiophene polymer is 1.4-2.1.

[0005] Furthermore, R in the above-mentioned dioxothiophene polymer is 2-ethylhexyl.

[0006] On the other hand, the present invention provides a method for preparing the dioxothiophene polymer, comprising the following steps: S1. Add dioxothiophene monomer to the reaction vessel. Lithium chloride was used. After evacuating the reaction vessel, nitrogen gas was introduced to atmospheric pressure. Dry solvent was added, followed by isopropyl magnesium chloride. After activation at room temperature for a certain period of time, the compound was obtained. .

[0007] S2. Add a nickel complex catalyst to the above reaction mixture, react at room temperature for a certain time, and then perform post-processing to obtain the dioxothiophene polymer. The specific reaction process is shown below.

[0008] .

[0009] Furthermore, the nickel complex catalyst is Ni(acac)2 / dppp.

[0010] Furthermore, in the post-processing operation, methanol is added to the reaction product to terminate the reaction, the obtained product is washed with methanol 4-5 times, dried under vacuum, the obtained product is dissolved in dichloromethane, washed with water 2-3 times, the organic phase is collected and concentrated under reduced pressure to obtain the dioxothiophene polymer.

[0011] On the other hand, the present invention provides a composition prepared using the above-described dioxothiophene polymer, the composition comprising the dioxothiophene polymer and a chiral inducing agent, wherein the chiral inducing agent is... or Chiral inducer molecules are small chiral molecules that, when interacting with the achiral dioxothiophene polymer backbone through non-covalent bonds, create a localized chiral microenvironment. This asymmetric environment causes the originally random dioxothiophene polymer backbone to adopt a dominant and stable helical conformation. This helical structure, guided by the chiral inducer, endows the entire polymer-inducer composition with macroscopic chirality, thereby enabling it to exhibit circular dichroism and circularly polarized luminescence.

[0012] The chiral inducer is present in the composition at a weight doping ratio of 15%-30%. A significant structure-activity relationship exists between the doping ratio and the CD signal intensity. When the doping ratio is below 15%, the chiral field strength is insufficient, making it difficult to effectively induce the polymer backbone to form a uniform helical conformation, resulting in a weak CD signal. Conversely, when the ratio exceeds 30%, the excessive inducer disrupts the originally ordered intermolecular interactions, interfering with the regular formation of helical nanofibers, thus weakening the chiral signal and ultimately reducing the CD value. By controlling the doping ratio at 20%, an optimal balance between chiral induction efficiency and photoelectric performance can be achieved. At this point, the polymer chain can form a highly ordered and stable supramolecular chiral structure, thereby generating strong and stable circular dichroism.

[0013] On the other hand, the present invention provides a chiral thin film prepared using the composition, wherein the thickness of the thin film is 140 nm.

[0014] On the other hand, the present invention provides a method for preparing the thin film, comprising the following steps: S1. Dissolve the dioxothiophene polymer in a solvent to prepare a first solution; S2. Dissolve the chiral inducer in a solvent to prepare a second solution; S3. Place a certain amount of the first solution into the reactor, then add a certain amount of the second solution dropwise into the first solution. After sealing the reactor for a certain period of time, complete the co-assembly of the dioxothiophene polymer and the chiral inducer to obtain the composition solution. S4. The composition solution is coated onto a substrate and annealed at a certain temperature for a certain period of time to obtain a thin film; Furthermore, the solvent is chlorobenzene.

[0015] Furthermore, the annealing temperature is 60-120℃.

[0016] Compared with existing technologies, the technical solution provided by this invention exhibits the following beneficial effects. This invention provides a method for long-range chiral modulation of achiral conjugated polydioxythiophene based on a simple chiral inducer. It uses a small-molecule chiral inducer to induce the achiral dioxythiophene conjugated polymer, and by adjusting the doping ratio and annealing temperature, achieves efficient long-range chiral transfer from the short-wavelength region associated with the inducer to the long-wavelength region of polydioxythiophene, thus achieving better technical results. Attached Figure Description

[0017] Appendix Figure 1 This is the nuclear magnetic resonance spectrum of thiophene monomer.

[0018] Appendix Figure 2 This is a gel permeation chromatogram of the dioxothiophene polymer prepared in Examples 1-5.

[0019] Appendix Figure 3 This is the nuclear magnetic resonance spectrum of the R-type chiral inducer.

[0020] Appendix Figure 4 This is the nuclear magnetic resonance spectrum of the S-type chiral inducer.

[0021] Appendix Figure 5 The circular dichroism of the composite films under different chiral inducer doping ratios is demonstrated.

[0022] Appendix Figure 6 The circular dichroism of the composite film is demonstrated at different temperatures.

[0023] Appendix Figure 7 It is the circular dichroism exhibited by the thin film of the S-type chiral inducer and dioxothiophene polymer composition. Detailed Implementation

[0024] To more clearly illustrate the technical solution of the present invention, the following specific embodiments will provide a clearer demonstration of the technical solution provided by the present invention. The present invention has many different embodiments and should not be construed as being limited to the embodiments described herein.

[0025] The synthesis method of the nickel complex catalyst used in this invention is as follows: Take a 25 mL polymerization flask, weigh 51.4 mg of nickel acetylacetone and 84.1 mg of 1,3-bis(diphenylphosphine)propane (ligand=dppp, Ni(acac)2 / dppp=1 / 1.02), add 10 mL of dry tetrahydrofuran under a nitrogen atmosphere, and stir at room temperature for later use.

[0026] Example 1 The synthetic route of the conjugated polydioxythiophene described in this invention is as follows, and the specific preparation process is as follows: 300 mg (0.5 mmol) of thiophene monomer is added to a 10 mL polymerization flask. The R group of the thiophene monomer is 2-ethylhexyl, and the proton NMR spectrum of the thiophene monomer is shown in the appendix. Figure 1 42.4 mg of lithium chloride was added, and the polymerization flask was evacuated and purged with nitrogen three times. Then, 2.5 mL of dry tetrahydrofuran was added, followed by 0.25 mL of isopropyl magnesium chloride. The mixture was activated at room temperature for 2 hours. Under nitrogen atmosphere, 1.6 mL of nickel complex catalyst solution was added, in which the ratio of thiophene monomer to nickel complex catalyst was 15:1. The mixture was reacted at room temperature for 1 hour to obtain dioxothiophene polymer.

[0027] In this embodiment, the dioxothiophene polymer is referred to as poly-1. 15 See appendix Figure 2 Gel permeation chromatography showed that the number-average molecular weight of this polymer was 6.83 × 10⁻⁶. 3 The molecular weight distribution is 1.45.

[0028] .

[0029] Example 2, Refer to Example 1, except that 0.8 mL of a nickel complex catalyst solution was added, wherein the ratio of thiophene monomer to nickel complex catalyst was 30:1, and the final prepared dioxothiophene polymer was denoted as poly-1. 30 See appendix Figure 2Gel permeation chromatography showed that the number-average molecular weight of this polymer was 12.5 × 10⁻⁶. 3 The molecular weight distribution is 1.87.

[0030] Example 3, The experimental procedure is the same as in Example 1, except that 0.5 mL of a nickel complex catalyst solution was added, wherein the ratio of thiophene monomer to nickel complex catalyst was 50:1. The final prepared dioxothiophene polymer is denoted as poly-1. 50 See appendix Figure 2 Gel permeation chromatography showed that the number-average molecular weight of this polymer was 21.1 × 10⁻⁶. 3 The molecular weight distribution is 2.0.

[0031] Example 4, The experimental procedure is the same as in Example 1, except that 0.35 mL of a nickel complex catalyst solution was added, wherein the ratio of thiophene monomer to nickel complex catalyst was 70:1. The final prepared dioxothiophene polymer is denoted as poly-1. 70 See appendix Figure 2 Gel permeation chromatography showed that the number-average molecular weight of this polymer was 30.1 × 10⁻⁶. 3 The molecular weight distribution is 1.94.

[0032] Example 5, The experimental procedure is the same as in Example 1, except that 0.25 mL of a nickel complex catalyst solution was added, wherein the ratio of thiophene monomer to nickel complex catalyst was 100:1. The final prepared dioxothiophene polymer is denoted as poly-1. 100 See appendix Figure 2 Gel permeation chromatography showed that the number-average molecular weight of this polymer was 44.3 × 10⁻⁶. 3 The molecular weight distribution is 1.88.

[0033] Appendix Figure 1 The gel chromatograms of the polymers prepared in Examples 1-5 are displayed in turn, arranged from right to left.

[0034] Example 6 The synthetic route of the chiral inducer described in this invention is shown below, and the specific preparation process is as follows: At room temperature, (R)-1,1'-bi-2-naphthol (5 g, 17.5 mmol), potassium carbonate (14.5 g, 105 mmol), and 1,4-dibromobutane (11.3 g, 52.5 mmol) were refluxed in acetonitrile solution at 80 °C, and the reaction was monitored until completion. The R-type chiral inducer was finally prepared.

[0035] Example 7 The experimental procedure is the same as in Example 6, except that (S)-1,1'-bi-2-naphthol (5 g, 17.5 mmol) was added to finally prepare the S-type chiral inducer.

[0036] The NMR spectrum of the R-type chiral inducer is shown in the appendix. Figure 3 The nuclear magnetic resonance spectrum of the S-type chiral inducer is shown in the appendix. Figure 4 .

[0037] Example 8 160 mg of the poly(dioxothiophene) conjugated polymer prepared in Example 3 was dissolved in 10 mL of chlorobenzene to obtain a 16 mg / mL solution. 950 μL, 900 μL, 850 μL, 800 μL, 700 μL, and 600 μL of this solution were added to six culture flasks, respectively. 80 mg of the chiral inducing agent prepared in Example 6 was dissolved in 5 mL of chlorobenzene solution. 50 μL, 100 μL, 150 μL, 200 μL, 300 μL, and 400 μL of the chiral induction solution were added dropwise to 950 μL, 900 μL, 850 μL, 800 μL, 700 μL, and 600 μL of the dioxothiophene polymer chlorobenzene solution, respectively, to prepare (RD) solutions. 0.05 -(poly-1 m ) 0.95 (RD) 0.1 -(poly-1 m ) 0.9 (RD) 0.15 -(poly-1 m ) 0.85 (RD) 0.2 -(poly-1 m ) 0.8 (RD) 0.3 -(poly-1 m ) 0.7 (RD) 0.4 -(poly-1 m ) 0.6 Six co-assembled solutions were prepared, and the culture flask mouth was covered with a rubber diaphragm for detection. Co-assembled solutions with different doping ratios were coated onto a glass substrate. The resulting co-assembled films were annealed at 120 °C for 30 minutes, achieving a film thickness of 140 nm, and then subjected to CD analysis. See appendix. Figure 5 As shown, the co-assembled film with a doping ratio of 20% exhibits the strongest circular dichroism in the 400-630 nm range. This is followed by the composition with a doping ratio of 15%, and then the composition with a doping ratio of 30%.

[0038] Example 9 The co-assembled thin film with a weight doping ratio of 20% from Example 8 was selected and annealed for 30 minutes at room temperature, 60 °C, 90 °C, and 120 °C, respectively. See Appendix. Figure 6 The composition exhibits the strongest circular dichroism at 120 °C, followed by 90 °C, and then 60 °C. When the temperature drops to room temperature, the composition no longer displays circular dichroism. Without heat annealing, the circular dichroism value is low. At room temperature, the composition may form a low-order chiral structure due to insufficient molecular thermal motion, resulting in a weak CD signal. Increasing the heat annealing temperature provides energy, promoting the arrangement of molecules in a more regular chiral pattern, forming a more ordered chiral composition, and thus enhancing the CD value.

[0039] Example 10 The experimental procedure is the same as in Example 8, except that 80 mg of the S-type chiral inducer prepared in Example 7 was dissolved in 5 mL of chlorobenzene solution to obtain a 16 mg / mL solution. 200 μL of the S-type chiral induction solution was then added dropwise to 800 μL of dioxothiophene polymer chlorobenzene solution to prepare (SD). 0.2 -(poly-1 m ) 0.8 The composition solution was prepared, and the culture flask was then covered with a rubber diaphragm for detection. The co-assembled solution was coated onto a glass substrate, and the resulting film was annealed at 120 °C for 30 minutes to a thickness of 70 nm. CD analysis was then performed, as shown in the attached figure. Figure 7 As shown, it exhibits the opposite circular dichroism.

[0040] The present invention has been illustrated with the above embodiments to describe the detailed process flow of the present invention. However, the present invention is not limited to the above detailed process flow, that is, it does not mean that the present invention must rely on the above detailed process flow to be implemented. Those skilled in the art should understand that any improvements to the present invention, equivalent substitutions of the raw materials of the product of the present invention, addition of auxiliary components, selection of specific methods, etc., all fall within the protection scope and disclosure scope of the present invention.

Claims

1. A dioxothiophene polymer, characterized in that, The structural formula of the dioxothiophene polymer is shown below. ； Wherein, R is an alkyl group; m is a positive integer that makes the number-average molecular weight of the dioxothiophene polymer between 5000 and 50000.

2. The dioxothiophene polymer according to claim 1, characterized in that, The molecular weight distribution of the dioxothiophene polymer is 1.4-2.

1.

3. The dioxothiophene polymer according to any one of claims 1-2, characterized in that, R is 2-ethylhexyl.

4. A method for preparing the dioxothiophene polymer according to any one of claims 1-3, characterized in that, Includes the following steps: S1. Add dioxothiophene monomer to the reaction vessel. Lithium chloride was used. After evacuating the reaction vessel, nitrogen gas was introduced to atmospheric pressure. Dry solvent was added, followed by isopropyl magnesium chloride. After activation at room temperature for a certain period of time, the compound was obtained. , S2. Add a nickel complex catalyst to the above reaction mixture, react at room temperature for a certain time, and then perform post-processing to obtain the dioxothiophene polymer; 。 5. The method according to claim 4, characterized in that, The nickel complex catalyst is Ni(acac)2 / dppp.

6. The method according to claim 4, characterized in that, The post-processing operation involves adding methanol to the reaction products to terminate the reaction, washing the resulting product with methanol 4-5 times, drying it under vacuum, dissolving the resulting product in dichloromethane, washing it with water 2-3 times, collecting the organic phase, and then concentrating it under reduced pressure to obtain the dioxothiophene polymer.

7. A composition prepared using any one of the dioxothiophene polymers according to claims 1-3, characterized in that, The composition comprises the dioxothiophene polymer and a chiral inducing agent; The chiral inducer is or .

8. The composition according to claim 7, characterized in that, The chiral inducer is present in the composition at a weight doping ratio of 15%-30%.

9. A chiral thin film prepared using the composition of any one of claims 7-8, characterized in that, The thickness of the film is 140 nm.

10. A method for preparing the chiral thin film as described in claim 9, characterized in that, Includes the following steps, S1. Dissolve the dioxothiophene polymer in a solvent to prepare a first solution; S2. Dissolve the chiral inducer in a solvent to prepare a second solution; S3. Place a certain amount of the first solution into the reactor, then add a certain amount of the second solution dropwise into the first solution. After sealing the reactor for a certain period of time, complete the co-assembly of the dioxothiophene polymer and the chiral inducer to obtain the composition solution. S4. The composition solution is coated onto a substrate and annealed at a certain temperature for a certain period of time to obtain a thin film; Preferably, the solvent is chlorobenzene. The annealing temperature is 60-120°C.

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