Photochromic solution, photochromic cellulose acetate film as well as preparation method and application of photochromic cellulose acetate film

Abstract

The invention discloses a photochromic solution, a photochromic cellulose acetate film and a preparation method and application of the photochromic cellulose acetate film and belongs to the technical field of photochromism, and the photochromic solution is prepared from methylene blue and triethanolamine. The obtained photochromic solution has excellent responsiveness under visible light, meanwhile, the raw material cost is low, the preparation process is simple, the color changing effect is obvious, the color fading rate is higher, obvious color changes are shown under light source irradiation, and the photochromic solution has wide application prospects and can be used in the fields of sensors, intelligent materials and the like.

Description

Technical Field

[0001] The invention relates to the technical field of photochromic technology, and in particular to a photochromic solution, a photochromic cellulose acetate film, and a preparation method and application thereof. Background Art

[0002] In the field of photochromism, there is a class of materials or compounds that change color when exposed to light or other external stimuli. This color change is usually caused by changes in the structure or chemical bonds within the material. This phenomenon has applications in many fields, including chemical sensors, optical devices, dyes, pigments, and display technology. In this field, people are constantly researching and developing new materials and methods to achieve more precise and controllable photochromic effects to meet the needs of different fields.

[0003] However, photochromic materials of traditional technologies may become unstable, have performance degradation or fail due to long-term use or the influence of external environmental conditions (such as humidity, temperature, etc.) or material problems. For example, the response speed of some photochromic materials may be slow and unsuitable for applications that require fast response, such as high-speed communication equipment or sensors, or some photochromic dye particles may lose their color conversion ability. Summary of the invention

[0004] The main purpose of the present invention is to provide a photochromic solution, a photochromic cellulose acetate film, and a preparation method and application thereof, aiming to solve the problems of slow response rate, low fading rate, complex color-changing reagent components and high cost of the photochromic cellulose acetate film.

[0005] To achieve the above object, the present invention provides a photochromic solution, which comprises the following components: methylene blue and triethanolamine.

[0006] In some embodiments, the methylene blue is 10 to 30 mg / L in terms of mass concentration; and / or,

[0007] In terms of mass concentration, the triethanolamine is 0.022 g / mL to 0.34 g / mL.

[0008] The present invention provides a photochromic cellulose acetate film, which comprises a cellulose acetate film and the photochromic solution as described above.

[0009] In some embodiments, the mass to surface area ratio of the cellulose acetate film is 0.00439 g / cm 2 ~0.0063g / cm 2 and / or,

[0010] The area of ​​the photochromic cellulose acetate film is 8 to 10 cm 2 .

[0011] The present invention provides a method for preparing a photochromic cellulose acetate film, comprising the following steps:

[0012] S10, providing a cellulose acetate film and the photochromic solution as described above;

[0013] S20, the cellulose acetate film absorbs the photochromic solution and is dried to obtain a photochromic cellulose acetate film.

[0014] In some embodiments, in step S20:

[0015] The adsorption amount of the photochromic solution by the cellulose acetate film is 0.35 ml / cm 2 ~0.45ml / cm 2 .

[0016] The drying temperature is 50-70°C; and / or,

[0017] The drying time is 2 to 6 hours.

[0018] In some embodiments, the steps of preparing the cellulose acetate film include:

[0019] S101, mixing cellulose, glacial acetic acid and a first solvent to obtain cellulose acetate;

[0020] S102, cooling and precipitating the cellulose acetate, and mixing it with a second solvent to obtain a cellulose acetate spinning solution;

[0021] S103, electrospinning the cellulose acetate spinning solution, collecting the electrospun fibers, and drying them to obtain a cellulose acetate film.

[0022] In some embodiments, in step S101, the first solvent includes concentrated sulfuric acid and acetic anhydride; and / or,

[0023] In step S102, the second solvent includes polyvinyl pyrrolidone and dichloromethane.

[0024] The present invention also provides a polarizer, comprising the photochromic cellulose acetate film as described above, or a photochromic cellulose acetate film prepared by the method for preparing the photochromic cellulose acetate film as described above.

[0025] The present invention also provides a photosensitive material, comprising the photochromic solution as described above.

[0026] The photochromic solution provided by the present invention is prepared by adding methylene blue and triethanolamine. Under the excitation of visible light, triethanolamine can be used as a sacrificial electron donor to reduce and quench methylene blue, causing fading (forming LMB). After stopping the illumination, LMB is oxidized into MB by dissolved oxygen in an aerobic environment, and the color is restored, so that the photochromic solution has excellent responsiveness under visible light. At the same time, the raw material cost is low, the preparation process is simple, the components are simple, the color change effect is obvious, the fading rate is higher, and obvious color change is shown under the illumination of light source. The solution has broad application prospects and can be used in the fields of sensors, smart materials, etc. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 It is a test effect diagram of the photochromic solution in Examples 2 to 7 of the present invention irradiated under a 300W full-spectrum light source;

[0028] Figure 2 It is a test schematic diagram of irradiating the photochromic solutions of Examples 2 to 7 of the present invention under a light source greater than 420 nm, stopping the irradiation after the solution fades, and recording the fading time and color recovery time;

[0029] Figure 3 It is a test schematic diagram of irradiating the photochromic solutions of Examples 8 to 13 of the present invention under a 300W full-spectrum light source, stopping the irradiation after the solution fades, and recording the fading time and color recovery time;

[0030] Figure 4 The photochromic solution of Example 4 of the present invention is irradiated for 2 minutes under a light source with a wavelength of 365 nm, and the effect diagrams before and after the irradiation are recorded;

[0031] Figure 5 The photochromic solution described in Example 4 of the present invention is irradiated with infrared light as a light source, specifically at a wavelength of ≥800nm ​​for 2h, and the effect diagrams before and after irradiation are recorded;

[0032] Figure 6 This is a test effect diagram of the photochromic cellulose acetate film described in Example 14 of the present invention under the irradiation of a full-spectrum light source;

[0033] Figure 7 This is a test effect diagram of the photochromic cellulose acetate film described in Example 15 of the present invention under full-spectrum light source irradiation. DETAILED DESCRIPTION

[0034] To make the purpose, technical scheme and advantages of the embodiment of the present invention clearer, the technical scheme in the embodiment of the present invention will be described clearly and completely below. If the specific conditions are not specified in the embodiment, it is carried out according to the normal conditions or the conditions recommended by the manufacturer. If the reagents or instruments used do not specify the manufacturer, they are all conventional products that can be purchased commercially. In addition, the meaning of "and / or" appearing in the full text includes three parallel schemes, taking "A and / or B" as an example, including scheme A, or scheme B, or schemes that A and B meet at the same time. In addition, the technical schemes between the various embodiments can be combined with each other, but must be based on the ability of ordinary technicians in the field to achieve. When the combination of technical solutions is contradictory or cannot be achieved, it should be considered that the combination of such technical solutions does not exist, and is not within the scope of protection required by the present invention. Based on the embodiments in the present invention, all other embodiments obtained by ordinary technicians in the field without making creative work belong to the scope of protection of the present invention.

[0035] In the field of photochromism, there is a class of materials or compounds that change color when exposed to light or other external stimuli. This color change is usually caused by changes in the structure or chemical bonds within the material. This phenomenon has applications in many fields, including chemical sensors, optical devices, dyes, pigments, and display technology. In this field, people are constantly researching and developing new materials and methods to achieve more precise and controllable photochromic effects to meet the needs of different fields.

[0036] Photochromic materials with traditional technologies may become unstable, have performance degradation or fail due to long-term use or the influence of external environmental conditions (such as humidity, temperature, etc.) or material problems. For example, some photochromic materials may have a slow response speed and are not suitable for applications that require a fast response, such as high-speed communication equipment or sensors, or may cause some photochromic dye particles to lose their color conversion ability.

[0037] In view of this, the present invention provides a photochromic solution, which comprises the following components: methylene blue and triethanolamine.

[0038] It should be noted that the photochromic solution is a special type of solution, the color of which can change significantly under light irradiation. This change is usually caused by conformational changes or chemical reactions of photosensitive molecules under light irradiation. The photochromic solution provided by the present invention, by adding methylene blue and triethanolamine, does not need to add other components, and the obtained photochromic solution has excellent responsiveness under visible light, and at the same time, the raw material cost is low, the preparation process is simple, the color change effect is obvious, the fading rate is higher, and it shows obvious color changes under light irradiation. It has broad application prospects and can be used in sensors, smart materials and other fields.

[0039] The photochromic solution provided by the present invention is prepared by adding methylene blue and triethanolamine. Under the excitation of visible light, triethanolamine can be used as a sacrificial electron donor to reduce and quench methylene blue, causing fading (forming LMB). After stopping the illumination, LMB is oxidized into MB by dissolved oxygen in an aerobic environment, and the color is restored, so that the photochromic solution has excellent responsiveness under visible light. At the same time, the raw material cost is low, the preparation process is simple, the components are simple, the color change effect is obvious, the fading rate is higher, and obvious color change is shown under the illumination of light source. The solution has broad application prospects and can be used in the fields of sensors, smart materials, etc.

[0040] In any embodiment of the present invention, the methylene blue is 10-30 mg / L in mass concentration; and / or the triethanolamine is 0.022 g / mL-0.34 g / mL in mass concentration. Within this mass range, the color changing effect of the obtained photochromic solution is more obvious.

[0041] It should be noted that triethanolamine is a key substance for color change, and it is found that when the mass concentration of triethanolamine is less than 0.022g / mL or greater than 0.34g / mL, the color change reaction time is relatively long. For example, in the range of 0.022g / mL to 0.34g / mL, the color change reaction time shortens with the increase of triethanolamine dosage. Excessive triethanolamine concentration will lead to prolonged color change response time and more delayed recovery time.

[0042] The present invention provides a photochromic cellulose acetate film, which comprises a cellulose acetate film and the photochromic solution as described above.

[0043] It should be noted that cellulose acetate film is widely used as a support and protective film for polarizers due to its excellent optical and physical properties. In the eyewear market, a type of photochromic glasses that can absorb 400-450nm high-energy blue light energy and stimulate the transformation of the internal photochromic dye particle structure, thereby deepening the color of polarized lenses and blocking visible light, is highly regarded by the market, and product demand is increasing rapidly. In addition, with the improvement of people's material living standards, the rise of outdoor sports has spawned a large number of outdoor sports display instruments, which are sought after by many young people. In order to avoid poor display contrast and blurred display caused by strong external light, photochromic cellulose acetate film can be used on polarizers to improve outdoor display contrast, reduce display power, save energy, and extend the service life of the instrument.

[0044] Furthermore, as the core material of photochromic polarizer, photochromic cellulose acetate film can not only block and absorb high-energy blue light, but also adjust the visual contrast in time according to the changes in the intensity of external ultraviolet light. This technical field requires that the photochromic polarizer has excellent light response rate and good durability, that is, the photochromic film has excellent light response rate and good durability.

[0045] In any embodiment of the present invention, the ratio of mass to surface area of ​​the cellulose acetate film is 0.00439 g / cm 2 ~0.0063g / cm 2 In this way, the adsorption of the photochromic solution on both sides of the film can be controlled to be uniform.

[0046] In any embodiment of the present invention, the area of ​​the photochromic cellulose acetate film is 8 to 10 cm 2 , can be 8cm 2 , 9cm 2 or 10cm 2 Within this range, if it is too large, the adsorption of the photochromic solution will be uneven, and if it is too small, the concentration of the photochromic solution adsorbed per unit area of ​​the film will be too high, resulting in a poor response rate; preferably 9cm 2 The photochromic cellulose acetate film has a better response rate based on the obvious color-changing effect.

[0047] The present invention provides a method for preparing a photochromic cellulose acetate film, comprising the following steps:

[0048] S10, providing a cellulose acetate film and the photochromic solution as described above;

[0049] S20, the cellulose acetate film absorbs the photochromic solution and is dried to obtain a photochromic cellulose acetate film.

[0050] It should be noted that photochromic cellulose acetate film is a special film material, usually composed of cellulose acetate and other photosensitive components. This film material will undergo a significant change in color after being irradiated with light of a specific wavelength. This change may be caused by conformational changes or chemical reactions of photosensitive molecules under light irradiation. Photochromic cellulose acetate film has the characteristics of fast response speed, bright colors, and good controllability. Therefore, it has a wide range of applications in optical devices, display technology, optical sensors and other fields. For example, it can be used as a key material for optical filters, optical modulators, visible light communication equipment, etc. The photochromic cellulose acetate film prepared by this preparation method has a simple process, low raw material cost, and the prepared photochromic cellulose acetate film has an obvious color change effect and a faster fading rate.

[0051] In any embodiment of the present invention, in step S20: the amount of the photochromic solution adsorbed by the cellulose acetate film is 0.35 ml / cm 2 ~0.45ml / cm2. Within this adsorption range, the cellulose acetate film can absorb as much photochromic solution as possible, and the adsorption amount can be 0.35ml / cm 2 、0.36ml / cm 2 、0.38ml / cm 2 、0.40ml / cm 2 、0.42ml / cm 2 or 0.45ml / cm 2 .

[0052] In any embodiment of the present invention, in step S20: the drying temperature is 50-70°C; within this temperature range, the two components in the photochromic solution can be dispersed and fixedly adsorbed on the cellulose acetate film, and the mixing temperature can be 50°C, 52°C, 55°C, 60°C, 62°C, 65°C or 50°C.

[0053] In any embodiment of the present invention, in step S20, the drying time is 2 to 6 hours, within which the cellulose acetate film can fully absorb the photochromic solution. The drying time can be 2 hours, 2.5 hours, 3 hours, 3.2 hours, 4 hours, 4.5 hours, 5 hours or 6 hours.

[0054] In any embodiment of the present invention, cellulose acetate can be purchased or made by oneself. When made by oneself, the preparation steps of the cellulose acetate film include:

[0055] S101, mixing cellulose, glacial acetic acid and a first solvent to obtain cellulose acetate;

[0056] S102, cooling and precipitating the cellulose acetate, and mixing it with a second solvent to obtain a cellulose acetate spinning solution;

[0057] S103, electrospinning the cellulose acetate spinning solution, collecting the electrospun fibers, and drying them to obtain a cellulose acetate film.

[0058] It should be noted that cellulose acetate is a biodegradable material with wide application potential, including medical, food packaging and environmental protection. However, traditional preparation methods usually require the use of toxic chemical reagents and high-energy consumption processes, which limits its widespread promotion in practical applications.

[0059] In any embodiment of the present invention, in step S101, the first solvent includes concentrated sulfuric acid and acetic anhydride; the first solvent is used to better dissolve cellulose to obtain cellulose acetate.

[0060] In any embodiment of the present invention, in step S102, the second solvent includes polyvinyl pyrrolidone and dichloromethane, and the second solvent used can effectively and evenly disperse the cellulose acetate to obtain a cellulose acetate spinning solution.

[0061] Specifically, the present invention provides a cellulose acetate film preparation step as follows:

[0062] S101, adding cellulose and acetic acid to concentrated sulfuric acid in a first solvent and heating it, adding acetic anhydride in the first solvent while stirring and controlling the reaction at a certain temperature, filtering the mixture while hot using a crucible filter to obtain a filtrate, and after the filtrate is cooled to room temperature, pouring the mixture into water for precipitation, and obtaining a precipitate of cellulose acetate;

[0063] S102, washing the cellulose acetate to neutrality, freeze-drying it, adding polyvinyl pyrrolidone, dichloromethane and glacial acetic acid in a second solvent, and continuously stirring at a constant temperature to obtain a cellulose acetate spinning solution;

[0064] S103, transferring the cellulose acetate spinning solution into a syringe, applying voltage between the tip and the receiver for electrostatic spinning, collecting the obtained electrospun fibers on tin foil, and drying the obtained electrospun fibers in a constant temperature oven to obtain the cellulose acetate film.

[0065] The present invention also provides a polarizer, comprising the photochromic cellulose acetate film as described above, or a photochromic cellulose acetate film prepared by the method for preparing the photochromic cellulose acetate film as described above, and therefore, also has the beneficial effects of the photochromic cellulose acetate film, which will not be described one by one here. As an example, it can be a sunglasses lens, etc.

[0066] The present invention also provides a photosensitive material, including the photochromic solution as described above, and therefore, also has the beneficial effects of the photochromic solution. Here, it is not repeated one by one. The application of the photochromic solution is very wide, not only limited to photosensitive dyes, but also in the fields of optical storage materials, optical switches, etc. As an example, among photosensitive dyes, photochromic solutions are often used in the preparation of photosensitive materials for applications such as laser printing and optical sensors. In the field of optical storage, photochromic solutions can be used to prepare optical recording materials to achieve storage and reading of optical information.

[0067] The technical solution of the present invention is further described in detail below in conjunction with specific embodiments. It should be understood that the following embodiments are only used to explain the present invention and are not used to limit the present invention.

[0068] Experimental Materials

[0069] Methylene blue, purchased from Tianjin Guangfu Fine Chemical Research Institute, catalog number: gfsr063;

[0070] Triethanolamine was purchased from Sinopharm Chemical Reagent Co., Ltd., catalog number: 10023118.

[0071] Example 1

[0072] A photochromic solution, wherein the concentration of methylene blue is 10 mg / L methylene blue and the concentration of triethanolamine is 0.03 g / mL based on 50 mL of the solution.

[0073] The difference between the photochromic solutions obtained in Examples 2 to 7 and Example 1 is that the concentration values ​​of methylene blue and triethanolamine in the photochromic solutions are changed, and the amounts of the components added in the photochromic solutions in Examples 2 to 7 are shown in Table 1:

[0074] Table 1 Components of the photochromic solution in Examples 2 to 7

[0075]

[0076] The photochromic solutions obtained in Examples 8 to 13 differ from those in Example 1 in that the concentration values ​​of methylene blue and triethanolamine in the photochromic solutions are changed, and the amounts of the components added to the photochromic solutions in Examples 8 to 13 are shown in Table 2:

[0077] Table 2 Components of the photochromic solution in Examples 8 to 13

[0078]

[0079]

[0080] Embodiment 14

[0081] A method for preparing a photochromic cellulose acetate film comprises the following steps:

[0082] S10, add 0.5g of cellulose and 8.6ml of glacial acetic acid into a 250ml three-necked flask, then add 14μl of concentrated sulfuric acid while stirring, heat to 50°C and stop heating, add 2ml of acetic anhydride dropwise while stirring and control the temperature not to exceed 70°C, continue to react at 50°C for 1.5h, and filter with a crucible filter while hot to obtain a filtrate; (2) after the filtrate is cooled to room temperature, pour it into water for precipitation, and the obtained precipitate is cellulose acetate. Wash the cellulose acetate until it is neutral and freeze-dry it at -50°C for 24h; (3) weigh 0.8g of cellulose acetate and place it in a spinning bottle, add 0.2 g of polyvinyl pyrrolidone, 4 ml of dichloromethane and 2 ml of glacial acetic acid were added, and stirred continuously at a speed of 500 rpm for 6 hours at a constant temperature of 45°C to obtain cellulose acetate spinning solution, and the spinning solution was transferred to a syringe, and a voltage of +10Kv, -5kV was applied between the tip and the receiver for electrostatic spinning, the needle tip distance was 10 cm, the injection speed was 0.4mm / min, the indoor temperature was controlled at 25°C, and the humidity was controlled at 60%. The obtained electrospun fibers were collected on tin foil, and the obtained electrospun fibers were placed in a constant temperature oven and kept at 60°C for drying for 3 hours to obtain cellulose acetate film.

[0083] S20, take 0.0395g, 9cm2 of the cellulose acetate film prepared in step S10 and spread it flat in a culture dish with a wire mesh, use a 1000μl pipette to take 3.15ml of the photochromic solution prepared in Example 4, and add it dropwise to the surface of the cellulose acetate film, wherein the photochromic solution of Example 4 is prepared by dissolving 2.5ml of triethanolamine in 50ml of 10mg / L methylene blue solution, and after complete adsorption, dry it at 60°C for 6h until the water is completely evaporated to obtain the corresponding photochromic cellulose acetate film.

[0084] Embodiment 15

[0085] A photochromic cellulose acetate film, the difference between the photochromic cellulose acetate film and Example 18 is that the photochromic solution and the cellulose acetate film are changed, and Example 15 is to add the photochromic solution prepared in Example 5 dropwise, take 4 ml with a 1000 μl pipette, and add it dropwise to 0.0567 g, 9 cm2 of cellulose acetate film, wherein the photochromic solution of Example 5 is prepared by dissolving 3 ml of triethanolamine in 50 ml of 10 mg / L methylene blue solution.

[0086] Comparative Example 1

[0087] The parameters of the preparation method of the photochromic cellulose acetate film obtained in Comparative Example 1 are different from those in Example 4 in that triethanolamine is not added to the photochromic solution.

[0088] Comparative Example 2

[0089] The parameters of the preparation method of the photochromic cellulose acetate film obtained in Comparative Example 2 are different from those in Example 4 in that methylene blue is not added to the photochromic solution.

[0090] Performance Testing

[0091] The photochromic solutions prepared in Examples 2 to 7 were irradiated under a 300W full-spectrum light source. After the solution faded, the irradiation was stopped and the fading time and color recovery time were recorded. The test results are as follows: Figure 1 As shown, Figure 1 The fading time schematic diagram and the recovery time schematic diagram in the embodiment 2 to 7 correspond to each other. Figure 1 It can be seen that: under the irradiation of the full-spectrum light source, Example 4 has the best effect, that is, when the photochromic solution is composed of 50 ml of 10 mg / L methylene blue and 2.5 ml of triethanolamine, it shows excellent responsiveness.

[0092] The photochromic solutions prepared in Examples 2 to 7 were irradiated under a light source with a wavelength of ≥420 nm. After the solution faded, the irradiation was stopped, and the fading time and color recovery time were recorded. The photochromic solutions in Examples 2 to 7 were irradiated under visible light conditions, specifically, under a light source with a wavelength of ≥420 nm. The test results are as follows: Figure 2 As shown by Figure 2 It can be seen that when the photochromic solution is composed of 50 ml of 10 mg / L methylene blue and 1.5 ml of triethanolamine under irradiation with a light source of wavelength ≥ 420 nm, it shows excellent responsiveness.

[0093] The photochromic solutions prepared in Examples 8 to 13 were irradiated under a 300W full-spectrum light source. After the solution faded, the irradiation was stopped and the fading time and color recovery time were recorded. The test results are as follows: Figure 3 As shown by Figure 3 It can be seen that under a 300w full-spectrum light source, when the photochromic solution is composed of 50ml 30mg / L methylene blue and 5ml triethanolamine, it has a fast color change performance. When the amount of triethanolamine is 7.5ml, it has a better color recovery performance. Considering the difference in fading time and recovery time between the two, the photochromic solution composed of 50ml 30mg / L methylene blue and 7.5ml triethanolamine is preferred.

[0094] The photochromic solution described in Example 4, that is, the photochromic solution composed of 50 ml of 10 mg / L methylene blue solution and 2.5 ml of triethanolamine, was irradiated under a light source with a wavelength of 365 nm, and the schematic diagrams before and after the irradiation were recorded. The results are shown in FIG. Figure 4 As shown in the figure: In this embodiment, the photochromic solution achieves an obvious fading effect when irradiated with a light source having a wavelength of 365 nm and an irradiation time of 2 minutes.

[0095] When the photochromic solution described in Example 4, i.e., the components of the photochromic solution are 50 ml of 10 mg / L methylene blue solution and 2.5 ml of triethanolamine, infrared light is used as the light source, specifically, after irradiation for 2 hours at a wavelength of ≥800 nm, the effect diagrams before and after irradiation are recorded. Figure 5 It can be seen that when the photochromic solution is irradiated with infrared light as the light source, specifically at a wavelength of ≥800 nm for 2 hours, the periphery of the solution fades, indicating that the photochromic solution has poor responsiveness to infrared light.

[0096] This is because: the energy of light of different wavelengths is different. Under visible light, triethanolamine is more likely to transfer electrons, causing methylene blue to fade due to reduction. Infrared light with a wavelength ≥ 800nm ​​has low energy and is difficult to generate electrons, which reduces the performance of reducing methylene blue.

[0097] The photochromic cellulose acetate films obtained in Example 14 and Example 15 were irradiated under a full-spectrum (ultraviolet light, visible light, infrared light) light source, and their fading time was recorded. After they were completely faded, the irradiation was stopped and their color recovery time was recorded. The measurement results were as follows: Figure 6 and Figure 7 Shown by: Figure 6 It can be seen that under this condition, complete fading can occur within 6 seconds, and after stopping the light, the color can be completely restored within 10.8 minutes; Figure 7 It can be seen that under this condition, complete fading will not occur within 6 seconds. After the light is stopped, the original color is completely restored after 5 minutes. This shows that after the photochromic solution is adsorbed by the cellulose acetate film, it can maintain excellent photochromic properties. At the same time, photochromism is greatly related to the amount of TEOA used.

[0098] The test results of Comparative Examples 1 and 2 are as follows: photochromism cannot occur under this condition, indicating that light cannot cause a solution containing only one component, methylene blue or triethanolamine, to change color.

[0099] The photochromic solution of the present invention comprises the following components: methylene blue and triethanolamine, and is responsive at all wavelengths, and more preferably, has a better response effect at a wavelength of 420 to 800 nm.

[0100] The above are only preferred embodiments of the present invention, and do not limit the patent scope of the present invention. For those skilled in the art, the present invention may have various changes and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the patent protection scope of the present invention.

Claims

1. A photochromic solution, characterized in that: The photochromic solution comprises the following components: methylene blue and triethanolamine.

2. A photochromic solution, characterized in that: In terms of mass concentration, the methylene blue is 10 to 30 mg / L; and / or, In terms of mass concentration, the triethanolamine is 0.022 g / mL to 0.34 g / mL.

3. A photochromic cellulose acetate film, characterized in that: The photochromic cellulose acetate film comprises a cellulose acetate film and the photochromic solution as claimed in claim 1 .

4. The photochromic cellulose acetate film according to claim 3, characterized in that: The ratio of mass to surface area of ​​the cellulose acetate film is 0.00439 g / cm 2 ~0.0063g / cm 2 and / or, The area of ​​the photochromic cellulose acetate film is 8 to 10 cm 2 .

5. A method for preparing a photochromic cellulose acetate film, characterized in that: The following steps are involved: S10, providing a cellulose acetate film and the photochromic solution as claimed in claim 1 or 2; S20, the cellulose acetate film absorbs the photochromic solution and is dried to obtain a photochromic cellulose acetate film.

6. The method for preparing the photochromic cellulose acetate film according to claim 1, characterized in that: In step S20: The adsorption amount of the photochromic solution by the cellulose acetate film is 0.35 ml / cm 2 ~0.45ml / cm 2 and / or, The drying temperature is 50-70°C; and / or, The drying time is 2 to 6 hours.

7. The method for preparing the photochromic cellulose acetate film according to claim 5 or 6, characterized in that: The preparation steps of the cellulose acetate film include: S101, mixing cellulose, glacial acetic acid and a first solvent to obtain cellulose acetate; S102, cooling and precipitating the cellulose acetate, and mixing it with a second solvent to obtain a cellulose acetate spinning solution; S103, electrospinning the cellulose acetate spinning solution, collecting the electrospun fibers, and drying to obtain a cellulose acetate film.

8. The method for preparing the photochromic cellulose acetate film according to claim 7, characterized in that: In step S101, the first solvent includes concentrated sulfuric acid and acetic anhydride; and / or, In step S102, the second solvent includes polyvinyl pyrrolidone and dichloromethane.

9. A polarizer, characterized in that: The invention comprises the photochromic cellulose acetate film as claimed in claim 3 or 4, or the photochromic cellulose acetate film prepared by the preparation method of the photochromic cellulose acetate film as claimed in claims 5 to 8.

10. A photosensitive material, characterized in that: Comprising the photochromic solution as claimed in claim 1 or 2.

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