Novel organic photochromic functional material and preparation method thereof

Abstract

The invention relates to the technical field of photochromic functional materials, in particular to a novel organic photochromic functional material and a preparation method thereof. The method comprises the following steps: S1, mixing a fluorane dye A with a molecular formula (1) and an alcohol protonation solvent B according to a volume ratio of 1: (1-5); s2, carrying out solvothermal reaction on the mixed solution at 150-200 DEG C to obtain a reactant, and collecting a precipitate; and S3, drying the precipitate in the step S2 to obtain the organic photochromic functional material. The novel organic photochromic functional material is simple in preparation process and green, and is yellow in darkness or a fluorescent lamp; under an ultraviolet lamp, the color is bright orange, and the yellow color and the bright orange color are reversibly interchanged.

Description

Technical Field

[0001] The invention relates to the technical field of photosensitive color-changing functional materials, and in particular to a novel organic photochromic functional material and a preparation method thereof. Background Art

[0002] With the continuous development of smart materials, especially stimuli-responsive materials, a subversive revolution has taken place in the field of original functional materials. Photochromic materials can undergo electron transfer or structural changes under the stimulation of ultraviolet light, visible light or infrared light, achieving a reversible change from one color to another. They have great application prospects in the fields of decoration, anti-counterfeiting, information storage and molecular switches. Among them, pure organic photochromic materials are widely synthesized due to their easy structural modification, fast response and rich color changes.

[0003] At present, common organic photochromic materials mainly include spiropyrans, salicylaldehyde condensed anilines, azos, condensed ring aromatics, viologens, diarylethenes, fulgide compounds, etc. Among them, spiropyrans are the earliest studied and most widely used organic photochromic materials. They rely on the rupture of the CO bond of spiropyran under ultraviolet light, and the two rings coplanarly form a larger conjugated system, thereby changing the absorption of light to change the color. The color change of this type of material is significant and the response is rapid, but its fatigue resistance and thermal stability have always been controversial. In contrast, diarylethene photochromic compounds can significantly improve the thermal stability and color change stability of the closed-ring structure generated under ultraviolet light by optimizing the type of substituted aromatics and undergoing trans-cis isomerization of the chemical structure. However, the development of this type of material faces great obstacles due to unfavorable factors such as complex preparation process, insufficient safety and high cost. Although fulgide compounds have good fatigue resistance and stability, they are not easy to return to the initial state after color change and the color change sensitivity is not high, which has certain limitations in practical applications. Similarly, other types of existing organic photochromic materials also have difficulty in achieving both color-changing effect and color-changing stability. Therefore, how to achieve this dual goal has become the focus of current researchers.

[0004] On the other hand, the synthesis of existing organic photochromic materials adopts conventional organic synthesis routes, which usually not only have complex reaction mechanisms, many reaction steps, long reaction processes, tedious post-processing steps, but also consume a lot of manpower and material resources. Therefore, it is urgent to break through the traditional organic synthesis method and seek a more convenient material synthesis route. Summary of the invention

[0005] The main purpose of the present invention is to provide a novel organic photochromic functional material and a preparation method thereof to solve the above technical problems.

[0006] To achieve the above object, the present invention provides a method for preparing a novel organic photochromic functional material, comprising the steps of:

[0007] S1: mixing a fluoran dye A having the following molecular formula (1) and an alcohol protonated solvent B in a volume ratio of 1:1-5;

[0008]

[0009] S2, subjecting the mixed solution to a solvothermal reaction at 150-200° C., and collecting the obtained reactant precipitate;

[0010] S3, drying the precipitate in step S2 to obtain an organic photochromic functional material.

[0011] Preferably, the alcohol protonated solvent is methanol or ethanol.

[0012] Preferably, the solvent thermal reaction in step S2 is a hydrothermal treatment carried out in a reactor.

[0013] Preferably, the hydrothermal treatment time is 1-6 hours.

[0014] Preferably, the step S2 further comprises heat preservation treatment of the product after the solvent thermal reaction, and then precipitating and collecting it after cooling.

[0015] The present invention also provides a novel organic photochromic functional material, which is prepared by the method for preparing the novel organic photochromic functional material as described in any one of the above items.

[0016] Preferably, the novel organic photochromic functional material is yellow in the dark or under fluorescent light; and bright orange under ultraviolet light, and the yellow and bright orange are reversibly interconvertible.

[0017] The novel organic photochromic functional material and its preparation method in the present invention, aiming at the color change range, color change stability and synthesis route of the existing organic photochromic materials, realizes the transformation of thermochromic dyes into photochromic materials by a one-step solvothermal method for the first time; the synthesis route is simple, reliable and green, which will provide new materials and new synthesis ideas for organic color-changing materials. The photochromic material is prepared by a one-step solvothermal reaction in a protonated solvent, the preparation process is simple and green, and the obtained product has a significant reversible color change from yellow to bright orange, and has good stability. The characteristics of the organic photochromic material prepared by the present invention are: in the dark or under fluorescent light, the color is yellow; under ultraviolet light, the color is bright orange. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] The accompanying drawings are part of the present invention and are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention, but do not constitute an improper limitation of the present invention. Obviously, the drawings described below are only some embodiments. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work. In the accompanying drawings:

[0019] Figure 1 This is the infrared spectrum of the organic photochromic material in Example 1 before and after ultraviolet light irradiation.

[0020] Figure 2 This is the X-ray photoelectron spectrum of the organic photochromic material in Example 1.

[0021] Figure 3 The UV-visible absorption spectrum of the organic photochromic material in Example 1 before and after color change.

[0022] Figure 4 These are electronic digital photos of the organic photochromic material in Example 1 before and after color change, with the left side showing before color change (yellow) and the right side showing after color change (bright orange).

[0023] Figure 5 1 is a color coordinate diagram of the organic photochromic material in Example 1 before and after color change, the upper figure is before color change (yellow), and the lower figure is after color change (bright orange).

[0024] Figure 6 These are electronic digital photos of the product in Example 2 before and after ultraviolet light irradiation, with the left side being before irradiation and the right side being after irradiation.

[0025] Figure 7 These are electronic digital photos of the product in Example 3 before and after ultraviolet light irradiation, with the left side being before irradiation and the right side being after irradiation. DETAILED DESCRIPTION

[0026] The following is a clear and complete description of the technical problems solved by the embodiments of the present invention, the technical solutions adopted, and the technical effects achieved in conjunction with the accompanying drawings and specific embodiments. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other equivalent or obviously modified embodiments obtained by ordinary technicians in this field without creative work fall within the scope of protection of the present invention. The embodiments of the present invention can be concretized in a variety of different ways as defined and covered in the claims.

[0027] It should be noted that in the following description, many specific details are given for ease of understanding, but it is obvious that the present invention can be implemented without these specific details.

[0028] It should be noted that, in the absence of clear limitation or conflict, the various embodiments of the present invention and the technical features therein can be combined with each other to form a technical solution.

[0029] Embodiment 1:

[0030] Synthesis of organic photochromic materials

[0031] 0.5 g of bright red pigment dye [6-(N-ethyl-4-toluidine)-2-methylfluoran] was added to 15 mL of ethanol solvent, stirred on a magnetic stirrer for 30 minutes to form a suspension, and then the mixed reaction liquid was introduced into a polytetrafluoroethylene reactor. The reactor was placed in an oven and kept at 180° C. for 4 hours. After it was naturally cooled to room temperature, it was centrifuged and washed three times with ethanol, and then dried in a vacuum oven at room temperature for 4 hours to obtain an organic photochromic material.

[0032] Testing of organic photochromic materials

[0033] The obtained organic photochromic material was ground and mixed with spectrally pure potassium bromide at a mass ratio of 1:50, and then pressed into a sheet material under a pressure of 8MPa, and infrared, ultraviolet visible absorption and color coordinates were tested. To test the data before and after color change, the sample was irradiated under ultraviolet light for 5 minutes.

[0034] Please combine Figures 1 to 5 , you can see, Figure 1 Infrared spectra of the organic photochromic material invented in the invention before and after ultraviolet light irradiation, with the horizontal axis being the wave number and the vertical axis being the intensity; the black curve represents before color change (yellow) and the red curve represents after color change (bright orange). Figure 2 It is the X-ray photoelectron energy spectrum of the organic photochromic material of the present invention, the abscissa is the bond energy, and the ordinate is the intensity; the first row from left to right is the full spectrum and the C1s fine spectrum, and the second row from left to right is the O1s and N1s fine spectra. Figure 3 It is the UV-visible absorption spectrum of the organic photochromic material of the present invention before and after color change, the abscissa is the wavelength, and the ordinate is the absorbance; the black curve represents before color change (yellow), and the red curve represents after color change (bright orange). Figure 4 The electronic digital photos of the organic photochromic material of the present invention before and after color change are shown, with the left side showing before color change (yellow) and the right side showing after color change (bright orange). Figure 5 1 is a color coordinate diagram of the organic photochromic material of the present invention before and after color change, the upper figure is before color change (yellow), and the lower figure is after color change (bright orange).

[0035] Embodiment 2:

[0036] 0.5 g of scarlet pigment dye [6-(N-ethyl-4-toluidine)-2-methylfluoran] was added to 15 mL of acetic acid solvent, stirred on a magnetic stirrer for 30 minutes to form a suspension, and then the mixed reaction liquid was introduced into a polytetrafluoroethylene reactor. The reactor was placed in an oven and kept at 180° C. for 4 hours. After it was naturally cooled to room temperature, it was centrifuged and washed three times with ethanol, and then dried in a vacuum oven at room temperature for 4 hours to obtain the final product.

[0037] Please combine Figure 6 , electronic digital photos of the product in this embodiment before and after ultraviolet light irradiation, the left side is before irradiation, and the right side is after irradiation, and there is no color change in both.

[0038] Embodiment 3:

[0039] 0.5 g of melanin dye [2-phenylamino-3-methyl-6-dibutylaminofluoran] was added to 15 mL of ethanol solvent, stirred on a magnetic stirrer for 30 minutes to form a suspension, and then the mixed reaction liquid was introduced into a polytetrafluoroethylene reactor. The reactor was placed in an oven and kept at 180°C for 4 hours. After it was naturally cooled to room temperature, it was centrifuged and washed three times with ethanol, and then dried in a vacuum oven at room temperature for 4 hours to obtain the final product.

[0040] Please combine Figure 7 , electronic digital photos of the product in this embodiment before and after ultraviolet light irradiation, the left side is before irradiation, and the right side is after irradiation, and there is no color change in both.

[0041] The embodiments described above are only used to illustrate the technical solutions of the present invention, rather than to limit the same. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that the technical solutions described in the aforementioned embodiments may still be modified, or some of the technical features may be replaced by equivalents. Such modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention, and should all be included in the protection scope of the present invention.

Claims

1. A method for preparing a novel organic photochromic functional material, characterized in that: Includes steps: S1: mixing a fluoran dye A having the following molecular formula (1) and an alcohol protonated solvent B in a volume ratio of 1:1-5; S2, subjecting the mixed solution to a solvothermal reaction at 150-200° C., and collecting the obtained reactant precipitate; S3, drying the precipitate in step S2 to obtain an organic photochromic functional material.

2. The method for preparing the novel organic photochromic functional material according to claim 1, characterized in that: The alcohol protonated solvent is methanol or ethanol.

3. The method for preparing the novel organic photochromic functional material according to claim 1, characterized in that: The solvent thermal reaction in step S2 is a hydrothermal treatment carried out in a reactor.

4. The method for preparing the novel organic photochromic functional material according to claim 3, characterized in that: The time of the hydrothermal treatment is 1-6 hours.

5. The method for preparing the novel organic photochromic functional material according to claim 1, characterized in that: The step S2 also includes heat preservation treatment of the product after the solvent thermal reaction, and then precipitating and collecting it after cooling.

6. A novel organic photochromic functional material, characterized in that: The novel organic photochromic functional material is prepared by the preparation method according to any one of claims 1 to 5.

7. The novel organic photochromic functional material according to claim 6, characterized in that: The novel organic photochromic functional material is yellow in the dark or under fluorescent light, and bright orange in ultraviolet light, and the yellow and bright orange are reversibly inter-convertible.

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