Copper iodine cluster-based thermochromic fluorescent fiber and its wet spinning preparation method and use

Abstract

The present application provides a copper-iodine cluster-based thermochromic fluorescent fiber and its wet spinning preparation method and use. The thermochromic fluorescent fiber comprises calcium alginate and a copper-iodine cluster compound, wherein the copper-iodine cluster compound comprises at least one of Cu4I4(4-benzylpyridine)4 and Cu4I4(4-tert-butylpyridine)4. Thus, the calcium alginate polymer base combined with the copper-iodine cluster compound can provide good protection without causing a significant loss of its emission intensity, thereby enabling the copper-iodine cluster-based thermochromic fiber to exhibit a reversible color change in the temperature range of 80K to 300K under ultraviolet light. The change is high in luminescence efficiency and good in stability.

Description

[0001] Priority information

[0002] This application claims priority to the Chinese patent application with patent application number 202510124368.7 and title “Thermochromic fluorescent fiber, preparation method and use thereof” filed with the State Intellectual Property Office of China on January 26, 2025, and the entire contents of which are incorporated by reference into this application. Technical Field

[0003] The present application belongs to the field of fiber materials, and specifically relates to a copper-iodine cluster-based thermochromic fluorescent fiber and a wet spinning preparation method and use thereof. Background Art

[0004] With the development of the economy and the progress of social, spiritual and material civilization, people are increasingly demanding the functionalization and color diversification of fiber textiles. Among them, fluorescent fibers have attracted special attention due to their great potential in various advanced photonic applications. For example, through special design and coding, fluorescent fibers can display unique colors or fluorescent patterns under specific conditions, making them widely used in the field of anti-counterfeiting; fluorescent color-changing fibers can be used in the development of smart textiles, such as color-changing clothing and wearable devices; fluorescent color-changing fibers can be used for environmental and health monitoring, such as in medical devices or sensors that change color according to the patient's physiological state to assist doctors in diagnosis and monitoring; in addition, designers can use the unique properties of fluorescent color-changing fibers to create innovative and attractive fashion works, adding a sense of fashion and personalization.

[0005] Fluorescent materials can be broadly categorized into the following categories: 1. Organic fluorescent dyes: These materials include aromatic fused-ring compounds. Common organic fluorescent dyes include rhodamine, fluorescein, and azo dyes. They have been widely used in bioimaging, fluorescent labeling, and photosensitive materials. However, organic fluorescent dyes suffer from poor fluorescence intensity and stability and are prone to photobleaching under prolonged illumination. 2. Rare earth inorganic fluorescent materials: These materials offer advantages such as strong absorption capacity and high conversion efficiency. The narrowband emission of the central ions in the rare earth complexes facilitates full-color display, and their physicochemical properties are stable. However, rare earth elements are relatively expensive, which can lead to high material costs, and the preparation of rare earth luminescent nanomaterials is relatively complex. 3. Quantum dot fluorescent dyes: Quantum dots exhibit broad excitation spectra and narrow emission spectra, and their fluorescence intensity is higher than that of commonly used organic fluorescent materials. However, most quantum dots contain heavy metals (such as Cd and Pb), which may release free heavy metal ions that are toxic to cells and biological tissues. Furthermore, the electric field confinement method is the most expensive and has the lowest yield for preparing quantum dots.

[0006] Copper-iodine cluster-based hybrid luminescent materials have the advantages of high crustal abundance, environmental friendliness, high efficiency and stability, and simple synthesis, making them an ideal alternative to traditional fluorescent materials. However, despite the huge application potential of copper-iodine cluster materials, the practical application of such materials remains a challenge. Current research on copper-iodine cluster materials is mainly based on their crystal form. In practical applications, crystalline materials have low mechanical strength, are brittle, and difficult to process. They also have no glass transition temperature, cannot be melted, and cannot be thermoformed like polymer materials, which greatly restricts their application in the industrial sector.

[0007] Therefore, existing fluorescent materials need to be improved. Summary of the Invention

[0008] The inventors of this application have conducted in-depth research on the technical problems existing in this field and found that one or more of the above technical problems can be solved by the following technical solutions.

[0009] In the first aspect of the present application, the present application proposes a copper-iodine cluster-based thermochromic fluorescent fiber, comprising: calcium alginate and a copper-iodine cluster compound, wherein the copper-iodine cluster compound comprises at least one of Cu4I4(4-benzylpyridine)4 and Cu4I4(4-tert-butylpyridine)4.

[0010] In some embodiments, the mass ratio of the calcium alginate to the copper iodine cluster is 20-200:1.

[0011] In some embodiments, the preparation method of Cu4I4(4-benzylpyridine)4 includes: mixing CuI with acetonitrile to obtain a mixed solution; adding 4-benzylpyridine dropwise into the mixed solution while stirring to form a white precipitate; separating the white precipitate, and then washing and drying to obtain Cu4I4(4-benzylpyridine)4.

[0012] In some embodiments, the preparation method of Cu4I4(4-tert-butylpyridine)4 includes: mixing CuI with acetonitrile to obtain a mixed solution; adding 4-tert-butylpyridine dropwise into the mixed solution while stirring to form a white precipitate; separating the white precipitate, and then washing and drying to obtain Cu4I4(4-tert-butylpyridine)4.

[0013] In some embodiments, the copper iodine cluster-based thermochromic fluorescent fiber has a diameter of 160 μm-180 μm.

[0014] In the second aspect of the present application, the present application proposes a method for preparing copper-iodine cluster-based thermochromic fluorescent fibers by wet spinning, comprising: mixing a sodium alginate aqueous solution with a copper-iodine cluster compound to obtain a spinning solution, wherein the copper-iodine cluster compound includes at least one of Cu4I4(4-benzylpyridine)4 and Cu4I4(4-tert-butylpyridine)4; wet spinning is performed using a calcium chloride aqueous solution as a coagulation bath to obtain copper-iodine cluster-based thermochromic fluorescent fibers.

[0015] In some embodiments, the mass concentration of the calcium chloride aqueous solution is 3%-10%.

[0016] In some embodiments, the spinning speed of the wet spinning process is 0.5 mL / min-3 mL / min.

[0017] In the third aspect of the present application, the present application proposes the use of the copper-iodine cluster-based thermochromic fluorescent fiber described in the first aspect or the copper-iodine cluster-based thermochromic fluorescent fiber obtained according to the method described in the present application in the fields of anti-counterfeiting, smart textiles, and environmental and health monitoring.

[0018] The present application has at least one of the following technical effects: the present application prepares a spinning solution by mixing a sodium alginate aqueous solution with a copper iodine cluster compound, and then performs wet spinning using a calcium chloride aqueous solution as a coagulation bath. The spinning solution and the coagulation bath undergo ion exchange to obtain a spinning fiber comprising calcium alginate and the copper iodine cluster compound, namely, a copper iodine cluster-based thermochromic fluorescent fiber. The calcium alginate polymer base combined with the copper iodine cluster compound can play a good protective role without causing a significant loss of its emission intensity. The copper iodine cluster-based thermochromic fluorescent fiber can show a color change under ultraviolet light in the temperature range of 80K-300K. The change is reversible, has high luminous efficiency and good stability, and its preparation process is simple, environmentally friendly, has high yield and low cost, and can realize the diversified fluorescent design and large-scale preparation of textiles. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] The embodiments illustrated herein are further described below with reference to the accompanying drawings, but the accompanying drawings are only for allowing those skilled in the art to better understand the present invention and are not intended to limit the scope of the present invention.

[0020] Figure 1 This is a SEM image of the copper-iodine cluster-based thermochromic fluorescent fiber obtained in Example 1;

[0021] Figure 2 This is a SEM image of the copper-iodine cluster-based thermochromic fluorescent fiber obtained in Example 4;

[0022] Figure 3The XRD patterns of the copper-iodine cluster-based thermochromic fluorescent fiber obtained in Example 1 and the copper-iodine cluster powder Cu4I4(4-benzylpyridine)4 and the copper-iodine cluster-based thermochromic fluorescent fiber obtained in Example 4 and the copper-iodine cluster powder Cu4I4(4-tert-butylpyridine)4 are shown;

[0023] Figure 4 This is the fluorescence emission spectrum of copper iodine cluster powder Cu4I4(4-tert-butylpyridine)4;

[0024] Figure 5 This is the fluorescence emission spectrum of copper iodine cluster powder Cu4I4(4-benzylpyridine)4;

[0025] Figure 6 This is the fluorescence emission spectrum of the copper-iodine cluster-based thermochromic fluorescent fiber obtained in Example 1;

[0026] Figure 7 This is a fluorescence emission spectrum of the copper-iodine cluster-based thermochromic fluorescent fiber obtained in Example 4;

[0027] Figure 8 Figure 2 is a graph showing the stability of the copper-iodine cluster-based thermochromic fluorescent fiber and copper-iodine cluster powder Cu4I4(4-benzylpyridine)4 obtained in Example 1 when stored in ambient air (20°C-35°C and 30%-40% RH), at high humidity (70% RH), immersed in room temperature water, at 50°C, 85°C, and under ultraviolet irradiation (300K);

[0028] Figure 9 Figure 4 is a graph showing the stability of the copper-iodine cluster-based thermochromic fluorescent fiber and copper-iodine cluster powder Cu4I4(4-tert-butylpyridine)4 obtained in Example 4 when stored in ambient air (20°C-35°C and 30%-40% RH), at high humidity (70% RH), immersed in room temperature water, at 50°C, 85°C, and under ultraviolet irradiation (300K);

[0029] Figure 10 The fluorescence color development photos of copper iodine cluster powder Cu4I4(4-benzylpyridine)4 after being immersed in ethanol, n-hexane, acetone, N,N-dimethylformamide (DMF) and toluene organic solvents for 5 hours;

[0030] Figure 11 These are fluorescence color development photos of the copper iodine cluster-based thermochromic fluorescent fiber of Example 1 after being immersed in ethanol, n-hexane, acetone, N,N-dimethylformamide (DMF), and toluene organic solvents for 5 hours, respectively;

[0031] Figure 12PL intensity comparison graphs of the copper iodine cluster-based thermochromic fluorescent fiber of Example 1 before and after immersion in ethanol, n-hexane, acetone, N,N-dimethylformamide (DMF) and toluene organic solvents for 5 hours;

[0032] Figure 13 This is a color development photograph of copper iodine cluster powder Cu4I4(4-benzylpyridine)4 under UV light at 300K;

[0033] Figure 14 This is a color development photograph of copper iodine cluster powder Cu4I4(4-tert-butylpyridine)4 under UV light at 300K;

[0034] Figure 15 The spinning solution obtained in Example 1 is a color photograph under natural light, UV light and 300K;.

[0035] Figure 16 These are color development photos of the spinning solution obtained in Example 4 under natural light, UV light, and 300K;

[0036] Figure 17 These are color development photos of the copper-iodine cluster-based thermochromic fluorescent fiber obtained in Example 1 under natural light, UV light, and 300K;

[0037] Figure 18 These are color development photos of the copper-iodine cluster-based thermochromic fluorescent fiber obtained in Example 4 under natural light, UV light, and 300K;

[0038] Figure 19 These are color development photos of the copper-iodine cluster-based thermotropic fluorescent fiber obtained in Example 1 at 80K and 300K and under ultraviolet light;

[0039] Figure 20 These are color development photos of the copper iodine cluster-based thermotropic fluorescent fiber obtained in Example 4 at 80K and 300K and under ultraviolet light. DETAILED DESCRIPTION

[0040] Hereinafter, the inventive concept of the present application will be further elaborated based on specific embodiments. However, the specific embodiments listed are for illustrative purposes only and are not intended to limit the scope of this application. Those skilled in the art will recognize that the specific features in any of the following embodiments can be used in any other embodiment as long as it does not deviate from the inventive concept described herein.

[0041] In one aspect of the present application, a copper-iodine cluster-based thermochromic fluorescent fiber is proposed, comprising calcium alginate and a copper-iodine cluster compound, wherein the copper-iodine cluster compound comprises at least one of Cu4I4(4-benzylpyridine)4 and Cu4I4(4-tert-butylpyridine)4.

[0042] Specifically, thermochromic fluorescent fibers are made by combining calcium alginate and copper iodine clusters. The Cu-Cu bond in the cluster center of the Cu4I4 (4-benzylpyridine) 4 copper iodine cluster shrinks as the temperature decreases, resulting in an emission peak in the high energy region (blue light band). When mixed with the original yellow light, it appears as white luminescence. The structural distortion in the low temperature section is reversible and will return to its original state at high temperatures, showing bright yellow fluorescence. The emission peak of Cu4I4 (4-tert-butylpyridine) 4 is at 640nm at 300K, and the luminescence shows a red shift when the temperature is lowered. The emission peak of the material is at 438nm at 80K. At room temperature, the core center of the Cu4I4 cluster is mainly composed of the ions of the ions. 3 CC emission, and partial halide-metal charge transfer ( 3 The XMCT process is the luminescence of the cluster core electron transition and has nothing to do with the ligand. However, at low temperatures, it manifests as a halide-pyridine ligand charge transfer ( 3 Therefore, the thermochromic luminescence of Cu4I4(4-tert-butylpyridine)4 is mainly attributed to 3 XLCT emission and 3 The relative intensity of CC emission changes. At low temperatures, the Cu-Cu distance becomes shorter, and the Cu4I4 cluster cores are more tightly bound, resulting in the excited triplet state of the cluster core electron transition ( 3 The copper-iodine cluster-based thermochromic fiber exhibits a reversible color change under ultraviolet light in the temperature range of 80K to 300K.

[0043] In some embodiments of the present application, the mass ratio of the calcium alginate to the copper-iodine cluster is 20-200:1, for example, 20:1, 50:1, 70:1, 90:1, 100:1, 120:1, 150:1, 170:1, 200:1, etc., or can be any range consisting of the above values. Thus, by mixing the polymer fiber and the copper-iodine cluster in this ratio, the reversibility and stability of the color change of the thermochromic fluorescent fiber in the temperature range of 80K-300K can be further improved.

[0044] In some embodiments of the present application, the preparation method of Cu4I4(4-benzylpyridine)4 includes: mixing CuI with acetonitrile to obtain a mixed solution; adding 4-benzylpyridine dropwise into the mixed solution while stirring to form a white precipitate; separating the white precipitate, and then washing and drying to obtain Cu4I4(4-benzylpyridine)4.

[0045] In some embodiments of the present application, the preparation method of Cu4I4(4-tert-butylpyridine)4 includes: mixing CuI with acetonitrile to obtain a mixed solution; adding 4-tert-butylpyridine dropwise into the mixed solution while stirring to form a white precipitate; separating the white precipitate, and then washing and drying to obtain Cu4I4(4-tert-butylpyridine)4.

[0046] In some embodiments of the present application, the diameter of the copper iodine cluster-based thermochromic fluorescent fiber is 160 μm-180 μm, for example, 160 μm, 165 μm, 170 μm, 175 μm, or 180 μm, or can be any range of the above values. Therefore, the thermochromic fluorescent fiber with this diameter has excellent stability.

[0047] In the second aspect of the present application, the present application proposes a method for preparing copper-iodine cluster-based thermochromic fluorescent fibers by wet spinning, comprising: mixing a sodium alginate aqueous solution with a copper-iodine cluster compound to obtain a spinning solution, wherein the copper-iodine cluster compound includes at least one of Cu4I4(4-benzylpyridine)4 and Cu4I4(4-tert-butylpyridine)4; wet spinning is performed using a calcium chloride aqueous solution as a coagulation bath to obtain copper-iodine cluster-based thermochromic fluorescent fibers.

[0048] Therefore, the present application obtains a spinning solution by mixing a sodium alginate aqueous solution with a copper iodine cluster compound, and then performs wet spinning using a calcium chloride aqueous solution as a coagulation bath. The spinning solution and the coagulation bath undergo ion exchange to obtain a spinning fiber comprising calcium alginate and the copper iodine cluster compound, namely, a copper iodine cluster-based thermochromic fluorescent fiber. The calcium alginate polymer base combined with the copper iodine cluster compound can play a good protective role without causing a significant loss of its emission intensity. The copper iodine cluster-based thermochromic fluorescent fiber can show color changes under ultraviolet light in the temperature range of 80K-300K. The change is reversible, the luminous efficiency is high and stable, and the preparation process is simple, environmentally friendly, high in yield and low in cost, and can realize the diversified fluorescent design and large-scale preparation of textiles.

[0049] In some embodiments of the present application, sodium alginate is first mixed with water to form a sodium alginate aqueous solution, and then copper iodine cluster powder is added and ultrasonically stirred for 4-5 hours to ensure that the copper iodine cluster is evenly dispersed in the sodium alginate aqueous solution to form a spinning solution. The spinning solution is then extruded through a spinneret by a metering pump at a spinning speed of 0.5 mL / min-3 mL / min into a coagulation bath of a CaCl2 aqueous solution with a concentration of 3 wt%-10 wt%. After the coagulation bath, the spun fibers are collected on a drum and finally washed with deionized water to remove excess CaCl2 attached to the fiber surface. The sample is then washed and dried at room temperature to obtain a copper iodine cluster-based thermochromic fluorescent fiber.

[0050] In the third aspect of the present application, the present application proposes the use of the copper-iodine cluster-based thermochromic fluorescent fiber described in the first aspect or the copper-iodine cluster-based thermochromic fluorescent fiber obtained according to the method described in the present application in the fields of anti-counterfeiting, smart textiles, and environmental and health monitoring.

[0051] The examples described below are exemplary and are intended only to explain the present invention and are not to be construed as limiting the present invention. Where specific techniques or conditions are not specified in the examples, the methods or conditions described in the literature within the art or in the product specifications were used. Where the manufacturer of the reagents or instruments is not specified, all are commercially available conventional products.

[0052] Preparation of Cu4I4(4-benzylpyridine)4(Cu4I4(bzpy)4)

[0053] CuI (0.19 g, 1 mmol) was dissolved in acetonitrile (8 mL) and stirred at room temperature to form a clear solution. Under vigorous stirring, 4-benzylpyridine (159 μL) was dropped into the CuI / acetonitrile solution to form a white precipitate in the mixed solution. The mixture was then centrifuged at 8000 rpm for 5 minutes to separate the precipitate, and washed three times with methanol. Finally, the white powder was dried in vacuo at 40 ° C for 24 h to obtain Cu4I4 (4-benzylpyridine) 4.

[0054] Preparation of Cu4I4(4-tert-butylpyridine)4(Cu4I4(tbpy)4):

[0055] CuI (0.19 g, 1 mmol) was dissolved in acetonitrile (8 mL) and stirred at room temperature to form a clear solution. Under vigorous stirring, 4-tert-butylpyridine (146 μL) was dropped into the CuI / acetonitrile solution to form a white precipitate in the mixed solution. The precipitate was separated by centrifugation at 8000 rpm for 5 minutes and washed three times with methanol. Finally, the obtained white powder was dried in vacuo at 40 ° C for 24 h to obtain Cu4I4 (4-tert-butylpyridine) 4.

[0056] Example 1

[0057] The method for preparing copper iodine cluster-based thermochromic fluorescent fibers by wet spinning comprises:

[0058] First, sodium alginate is mixed with water to prepare a sodium alginate aqueous solution with a mass concentration of 4wt%, and then copper iodine cluster powder Cu4I4(4-benzylpyridine)4 is added and ultrasonically stirred for 4-5h to ensure that the copper iodine cluster is evenly dispersed in the sodium alginate aqueous solution to prepare a spinning solution. The spinning solution is then extruded through a spinneret by a metering pump at a spinning speed of 1mL / min into a coagulation bath of a CaCl2 aqueous solution with a concentration of 5wt%. After the coagulation bath, the spun fibers are collected on a drum (draw ratio of 1.5:1) and finally washed with deionized water to remove excess CaCl2 attached to the fiber surface. The sample is then washed and dried at room temperature to obtain copper iodine cluster-based thermochromic fluorescent fibers with a diameter of 160μm-180μm (the mass ratio of calcium alginate to copper iodine cluster is 100:1).

[0059] Example 2

[0060] The method for preparing copper iodine cluster-based thermochromic fluorescent fibers by wet spinning comprises:

[0061] First, sodium alginate is mixed with water to prepare a sodium alginate aqueous solution with a mass concentration of 4wt%, and then copper iodine cluster powder Cu4I4(4-benzylpyridine)4 is added and ultrasonically stirred for 4-5h to ensure that the copper iodine cluster is evenly dispersed in the sodium alginate aqueous solution to prepare a spinning solution. The spinning solution is then extruded through a spinneret by a metering pump at a spinning speed of 1mL / min into a coagulation bath of a CaCl2 aqueous solution with a concentration of 5wt%. After the coagulation bath, the spun fibers are collected on a drum (draw ratio of 1.5:1) and finally washed with deionized water to remove excess CaCl2 attached to the fiber surface. The sample is then washed and dried at room temperature to obtain copper iodine cluster-based thermochromic fluorescent fibers with a diameter of 160μm-180μm (the mass ratio of calcium alginate to copper iodine cluster is 20:1).

[0062] Example 3

[0063] The method for preparing copper iodine cluster-based thermochromic fluorescent fibers by wet spinning comprises:

[0064] First, sodium alginate is mixed with water to prepare a sodium alginate aqueous solution with a mass concentration of 4wt%, and then copper iodine cluster powder Cu4I4(4-benzylpyridine)4 is added and ultrasonically stirred for 4-5h to ensure that the copper iodine cluster is evenly dispersed in the sodium alginate aqueous solution to prepare a spinning solution. The spinning solution is then extruded through a spinneret by a metering pump at a spinning speed of 1mL / min into a coagulation bath of a CaCl2 aqueous solution with a concentration of 5wt%. After the coagulation bath, the spun fibers are collected on a drum (draw ratio of 1.5:1) and finally washed with deionized water to remove excess CaCl2 attached to the fiber surface. The sample is then washed and dried at room temperature to obtain copper iodine cluster-based thermochromic fluorescent fibers with a diameter of 160μm-180μm (the mass ratio of calcium alginate to copper iodine cluster is 200:1).

[0065] Example 4

[0066] The method for preparing copper iodine cluster-based thermochromic fluorescent fibers by wet spinning comprises:

[0067] First, sodium alginate is mixed with water to prepare a sodium alginate aqueous solution with a mass concentration of 4wt%, and then copper iodine cluster Cu4I4(4-tert-butylpyridine)4 powder is added and ultrasonically stirred for 4 hours to ensure that the copper iodine cluster is evenly dispersed in the sodium alginate aqueous solution to prepare a spinning solution. The spinning solution is then extruded through a spinneret by a metering pump at a spinning speed of 1mL / min into a coagulation bath of a CaCl2 aqueous solution with a concentration of 5wt%. After the coagulation bath, the spun fibers are collected on a drum (draw ratio of 1.5:1) and finally washed with deionized water to remove excess CaCl2 attached to the fiber surface. The sample is then washed and dried at room temperature to obtain copper iodine cluster-based thermochromic fluorescent fibers with a diameter of 160μm-180μm (the mass ratio of calcium alginate to copper iodine cluster is 100:1).

[0068] Example 5

[0069] The method for preparing copper iodine cluster-based thermochromic fluorescent fibers by wet spinning comprises:

[0070] First, sodium alginate is mixed with water to prepare a sodium alginate aqueous solution with a mass concentration of 4wt%, and then copper iodine cluster Cu4I4(4-tert-butylpyridine)4 powder is added and ultrasonically stirred for 4h to ensure that the copper iodine cluster is evenly dispersed in the sodium alginate aqueous solution to prepare a spinning solution. The spinning solution is then extruded through a spinneret by a metering pump at a spinning speed of 1mL / min into a coagulation bath of a CaCl2 aqueous solution with a concentration of 5wt%. After the coagulation bath, the spun fibers are collected on a drum (draw ratio of 1.5:1) and finally washed with deionized water to remove excess CaCl2 attached to the fiber surface. The sample is then washed and dried at room temperature to obtain copper iodine cluster-based thermochromic fluorescent fibers with a diameter of 160μm-180μm (the mass ratio of calcium alginate to copper iodine cluster is 20:1).

[0071] Example 6

[0072] The method for preparing copper iodine cluster-based thermochromic fluorescent fibers by wet spinning comprises:

[0073] First, sodium alginate is mixed with water to prepare a sodium alginate aqueous solution with a mass concentration of 4wt%, and then copper iodine cluster Cu4I4(4-tert-butylpyridine)4 powder is added and ultrasonically stirred for 4 hours to ensure that the copper iodine cluster is evenly dispersed in the sodium alginate aqueous solution to prepare a spinning solution. The spinning solution is then extruded through a spinneret by a metering pump at a spinning speed of 1mL / min into a coagulation bath of a CaCl2 aqueous solution with a concentration of 5wt%. After the coagulation bath, the spun fibers are collected on a drum (draw ratio of 1.5:1) and finally washed with deionized water to remove excess CaCl2 attached to the fiber surface. The sample is then washed and dried at room temperature to obtain copper iodine cluster-based thermochromic fluorescent fibers with a diameter of 160μm-180μm (the mass ratio of calcium alginate to copper iodine cluster is 200:1).

[0074] The prepared copper iodine cluster-based thermochromic fluorescent fibers were characterized as follows:

[0075] 1. The morphology of the copper-iodine cluster-based thermochromic fluorescent fibers was characterized using scanning electron microscopy (SEM). Figure 1 (Copper iodine cluster-based thermochromic fluorescent fiber obtained in Example 1) and Figure 2 As shown in (Copper-iodine cluster-based thermochromic fluorescent fibers obtained in Example 4), there are many grooves on the surfaces of both thermochromic fluorescent fibers, which may be caused by the volatilization of the solvent after stretching in the coagulation bath, and there are no visible aggregated particles on the fiber surface, indicating that the copper-iodine clusters are uniformly dispersed in the fibers.

[0076] 2. The composition and phase purity of the copper iodine cluster-based thermochromic fluorescent fibers obtained in Example 1 and Example 4 were characterized by X-ray diffraction (XRD). Figure 3As shown, the copper-iodine cluster-based thermochromic fluorescent fiber obtained in Example 1 showed a peak corresponding to that of the copper-iodine cluster powder Cu4I4(4-benzylpyridine)4, and the copper-iodine cluster-based thermochromic fluorescent fiber obtained in Example 4 showed a peak corresponding to that of the copper-iodine cluster powder Cu4I4(4-tert-butylpyridine)4, indicating the successful integration of the copper-iodine cluster and calcium alginate, and proving the stability of the copper-iodine cluster framework during the entire spinning process.

[0077] 3. The fluorescence emission spectra of the copper iodine cluster thermochromic fluorescent fiber, copper iodine cluster powder Cu4I4(4-benzylpyridine)4 and copper iodine cluster powder Cu4I4(4-tert-butylpyridine)4 obtained in Examples 1 and 4 were characterized at 300K. 350nm was selected as the excitation wavelength for the copper iodine cluster and 330nm was selected as the excitation wavelength for the thermochromic fluorescent fiber. The test results of copper iodine cluster powder Cu4I4(4-tert-butylpyridine)4 are shown in Figure 2. Figure 4 The test results of copper iodine cluster powder Cu4I4(4-benzylpyridine)4 are as follows Figure 5 As shown by Figure 4 and 5 It can be seen that the emission of copper iodine cluster powder Cu4I4(4-benzylpyridine)4 and copper iodine cluster powder Cu4I4(4-tert-butylpyridine)4 are both single peak emission, and their fluorescence emission wavelengths are 580nm and 640nm respectively, and their fluorescence colors are yellow and orange respectively. The test results of the copper iodine cluster-based thermochromic fluorescent fiber obtained in Example 1 are shown in FIG. Figure 6 As shown in the figure, the test results of the copper iodine cluster-based thermochromic fluorescent fiber obtained in Example 4 are as follows: Figure 7 As shown by Figure 6 and 7 The emission wavelengths of the copper-iodine cluster-based thermochromic fluorescent fibers obtained in Examples 1 and 4 were 577 nm and 642 nm, respectively, and their fluorescent colors were yellow and orange, respectively. This indicates that the fluorescence emission wavelengths and emission colors of the copper-iodine cluster-based thermochromic fluorescent fibers obtained in Examples 1 and 4 and their corresponding copper-iodine cluster complexes correspond well, indicating that the copper-iodine cluster complexes remain stable during the composite process with the calcium alginate substrate without any structural changes or degradation.

[0078] 4. The stability of the copper iodine cluster thermochromic fluorescent fibers, copper iodine cluster powder Cu4I4(4-benzylpyridine)4 and copper iodine cluster powder Cu4I4(4-tert-butylpyridine)4 obtained in Examples 1 and 4 was characterized: Figure 8 and 9 As shown, Figure 8a, b, c, d, e and F are the stability curves of the copper iodine cluster-based thermochromic fluorescent fiber and the copper iodine cluster powder Cu4I4(4-benzylpyridine)4 obtained in Example 1 when stored in ambient air (20°C-35°C and 30%-40% RH), at high humidity (70% RH), immersed in room temperature water, at 50°C, 85°C and under ultraviolet irradiation (300K), respectively. Figure 9 Figures a, b, c, d, e, and F are the stability curves of the copper iodine cluster-based thermochromic fluorescent fiber and the copper iodine cluster powder Cu4I4(4-tert-butylpyridine)4 obtained in Example 2 in ambient air (20°C-35°C and 30%-40% RH), in high humidity (70% RH), immersed in water, at 50°C, 85°C, and under ultraviolet irradiation (300K), respectively. Figure 8 a, b and c and Figure 9 As shown in a, b and c, when the copper iodine cluster powder Cu4I4(4-benzylpyridine)4 and the thermochromic fluorescent fiber obtained from the copper iodine cluster in Example 1, as well as the thermochromic fluorescent fiber obtained from Example 2 and the copper iodine cluster powder Cu4I4(4-tert-butylpyridine)4 were stored in ambient air (20°C-35°C and 30%-40% RH), in high humidity (70% RH), and immersed in water for 15 days, the PL intensity of the copper iodine cluster-based thermochromic fluorescent fibers obtained from Example 1 and Example 4 remained stable (>98%) and were both higher than those of the corresponding copper iodine cluster powders, indicating that the copper iodine cluster-based thermochromic fluorescent fibers obtained from Example 1 and Example 4 have outstanding stability to high humidity, water and oxygen. Figure 8 d and e and Figure 9 As shown in Figures d and e, the copper-iodine cluster-based thermochromic fluorescent fibers obtained in Example 1 and Example 4 exhibited a PL intensity of more than 95% when stored at 50°C for 15 days, indicating excellent thermal stability. When stored at 85°C for 15 days, a PL intensity of more than 75% was observed, which is much greater than that of the corresponding copper-iodine clusters. Figure 8 Medium f and Figure 9 It can be seen from Figure 5 that the copper iodine cluster-based thermochromic fluorescent fibers obtained in Example 1 and Example 4 maintain 94.3% and 93.7% of the luminous intensity respectively after being irradiated with ultraviolet light for 300 minutes, and there is no obvious loss or shift in the luminous intensity.

[0079] The copper iodine cluster thermochromic fluorescent fiber of Example 1 and the corresponding copper iodine cluster powder Cu4I4(4-benzylpyridine)4 were immersed in ethanol, n-hexane, acetone, N,N-dimethylformamide (DMF) and toluene organic solvents for 5 h, and then subjected to fluorescence irradiation at 300 K. Figure 10(Copper iodine cluster powder Cu4I4(4-benzylpyridine)4) It can be seen that the copper iodine cluster powder Cu4I4(4-benzylpyridine)4 still maintains yellow in ethanol and n-hexane, but loses its fluorescence properties in acetone, DMF and toluene; while the reference Figure 11 (Example 1 Copper iodine cluster based thermochromic fluorescent fiber) It can be seen that the copper iodine cluster based thermochromic fluorescent fiber of Example 1 still maintains its fluorescent properties in organic solvents such as ethanol, n-hexane, acetone, N, N-dimethylformamide (DMF) and toluene. Figure 12 The PL intensity change of the copper-iodine cluster-based thermochromic fluorescent fiber in Example 1 can also be ignored, which shows that the copper-iodine cluster-based thermochromic fluorescent fiber has high organic solvent stability. It is speculated that the combination of the sodium alginate polymer group may protect the copper-iodine cluster powder.

[0080] 6. The copper iodine cluster powder Cu4I4(4-benzylpyridine)4 and copper iodine cluster powder Cu4I4(4-tert-butylpyridine)4, the spinning solution obtained in Examples 1-6, and the copper iodine cluster-based thermochromic fluorescent fiber were characterized by color change under natural light, ultraviolet light, and 80K-300K. Figure 13 This is a photo of copper iodine cluster powder Cu4I4(4-benzylpyridine)4 under ultraviolet light and 300K, which appears yellow. Figure 14 This is a photo of copper iodine cluster powder Cu4I4(4-tert-butylpyridine)4 under ultraviolet light and 300K, which appears orange; Figure 15 The following are photos of the spinning solution obtained in Example 1 under natural light, ultraviolet light, and 300K. The original color of the fiber is retained under natural light, but yellow fluorescence is displayed under ultraviolet light. Figure 16 The following are photos of the spinning solution obtained in Example 4 under natural light, ultraviolet light, and 300K. The original color of the fiber is retained under natural light, but it shows orange fluorescence under ultraviolet light. Figure 17 These are photos of the copper-iodine cluster-based thermochromic fluorescent fiber obtained in Example 1 under natural light, ultraviolet light, and 300K. The fiber retains its original color under natural light, but exhibits yellow fluorescence under ultraviolet light; Figure 18 These are photos of the copper iodine cluster-based thermochromic fluorescent fiber obtained in Example 4 under natural light, ultraviolet light, and 300K. The fiber maintains its original color under natural light, but exhibits orange fluorescence under ultraviolet light.

[0081] Figure 19The copper-iodine cluster-based thermofluorescent fiber obtained in Example 1 appears white at 80K and 300K and under ultraviolet light. When the temperature is raised to 300K, it appears yellow under ultraviolet light. After the temperature is lowered to 80K, it returns to white under ultraviolet light, indicating that the copper-iodine cluster-based thermofluorescent fiber can change from white to yellow under ultraviolet light and in the temperature range of 80K-300K, and the color change process is reversible. The copper-iodine cluster-based thermofluorescent fibers obtained in Examples 2 and 3 appear white under ultraviolet light and at 80K. When the temperature is raised to 300K, it appears yellow under ultraviolet light, and after the temperature is lowered to 80K, it returns to white under ultraviolet light, indicating that the copper-iodine cluster-based thermofluorescent fiber can change from white to yellow under ultraviolet light and in the temperature range of 80K-300K, and the color change process is reversible.

[0082] Figure 20 The copper-iodine cluster-based thermofluorescent fiber obtained in Example 4 appears purple at 80K and 300K, and under ultraviolet light. When the temperature is raised to 300K, it appears orange under ultraviolet light. After the temperature is lowered to 80K, it returns to purple under ultraviolet light, indicating that the copper-iodine cluster-based thermofluorescent fiber can change from purple to orange under ultraviolet light and in the temperature range of 80K-300K, and the color change process is reversible. The copper-iodine cluster-based thermofluorescent fibers obtained in Examples 5 and 6 appear purple under ultraviolet light and at 80K, but when the temperature is raised to 300K, it appears orange under ultraviolet light, and after the temperature is lowered to 80K, it returns to purple under ultraviolet light, indicating that the copper-iodine cluster-based thermofluorescent fiber can change from purple to orange under ultraviolet light and in the temperature range of 80K-300K, and the color change process is reversible.

[0083] The above description is merely a specific embodiment of the invention covered by this application, but the scope of protection of this application is not limited thereto. Any changes or substitutions that can be easily conceived by a person skilled in the art within the technical scope disclosed in this application should be included in the scope of protection of this application. Therefore, the scope of protection of this application should be based on the scope of protection of the claims.

Claims

1. A copper-iodine cluster-based thermochromic fluorescent fiber, characterized in that: include: Calcium alginate and a copper iodine cluster, wherein the copper iodine cluster comprises at least one of Cu4I4(4-benzylpyridine)4 and Cu4I4(4-tert-butylpyridine)4.

2. The copper-iodine cluster-based thermochromic fluorescent fiber according to claim 1, characterized in that: The mass ratio of the calcium alginate to the copper iodine cluster is 20-200:

1.

3. The copper-iodine cluster-based thermochromic fluorescent fiber according to claim 1 or 2, characterized in that: The preparation method of Cu4I4(4-benzylpyridine)4 comprises: Mixing CuI and acetonitrile to obtain a mixed solution; While stirring, 4-benzylpyridine was added dropwise to the mixed solution to form a white precipitate; The white precipitate was isolated, washed and dried to give Cu4I4(4-benzylpyridine)4.

4. The copper-iodine cluster-based thermochromic fluorescent fiber according to claim 1 or 2, characterized in that: The preparation method of Cu4I4(4-tert-butylpyridine)4 comprises: Mixing CuI and acetonitrile to obtain a mixed solution; While stirring, 4-tert-butylpyridine was added dropwise to the mixed solution to form a white precipitate; The white precipitate was isolated, washed and dried to give Cu4I4(4-tert-butylpyridine)4.

5. The copper-iodine cluster-based thermochromic fluorescent fiber according to claim 1 or 2, characterized in that: The diameter of the copper iodine cluster-based thermochromic fluorescent fiber is 160 μm-180 μm.

6. A method for preparing copper iodine cluster-based thermochromic fluorescent fibers by wet spinning, characterized in that: include: Mixing a sodium alginate aqueous solution with a copper iodine cluster to obtain a spinning solution, wherein the copper iodine cluster comprises at least one of Cu4I4(4-benzylpyridine)4 and Cu4I4(4-tert-butylpyridine)4; Copper iodine cluster-based thermochromic fluorescent fibers were obtained by wet spinning using calcium chloride aqueous solution as coagulation bath.

7. The method according to claim 6, characterized in that The mass concentration of the calcium chloride aqueous solution is 3%-10%.

8. The method according to claim 6, characterized in that The spinning speed of the wet spinning process is 0.5 mL / min-3 mL / min.

9. Use of the copper-iodine cluster-based thermochromic fluorescent fiber according to any one of claims 1 to 5 or the copper-iodine cluster-based thermochromic fluorescent fiber obtained by the method according to any one of claims 6 to 8 in the fields of anti-counterfeiting, smart textiles, and environmental and health monitoring.

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