Copper iodine cluster-based thermochromic fluorescent fiber as well as wet spinning preparation method and application thereof

Abstract

The invention provides a copper-iodine cluster-based thermochromic fluorescent fiber and a wet spinning preparation method and application thereof, the copper-iodine cluster-based thermochromic fluorescent fiber comprises calcium alginate and a copper-iodine cluster compound, and the copper-iodine cluster compound comprises at least one of Cu4I4 (4-benzyl pyridine) 4 and Cu4I4 (4-tert-butyl pyridine) 4. Therefore, the calcium alginate polymer base combined with the copper-iodine cluster compound can play a good protection role and does not cause obvious loss of emission intensity, so that the copper-iodine cluster-based thermochromic fiber can show color change under ultraviolet light within a temperature range of 80K-300K, the change is reversible, the luminous efficiency is high, and the stability is relatively good.

Description

[0001] Priority information

[0002] This application requests the priority of the Chinese patent application with patent application number 202510124368.7 and title “Thermochromic fluorescent fiber and its preparation method and use” filed with the State Intellectual Property Office of China on January 26, 2025, and the entire contents are incorporated by reference in 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 economy and the progress of social spiritual and material civilization, people have increasingly higher requirements for the functionalization and color diversification of fiber textiles. Among them, fluorescent fibers have received special attention due to their great potential in various advanced photonic applications. For example, through special design and coding, fluorescent fibers can show unique colors or fluorescent patterns under certain conditions, and thus are 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, wearable devices, etc.; fluorescent color-changing fibers can be used for environmental and health monitoring, such as changing colors in medical devices or sensors according to the patient's physiological state to help doctors diagnose and monitor; 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 mainly divided into the following categories: 1. Organic fluorescent dyes: This type of fluorescent material includes aromatic condensed ring compounds, etc. Common organic fluorescent dyes include rhodamine, fluorescein, azo dyes, etc., which have been widely used in biological imaging, fluorescent labeling, photosensitive materials, etc. The fluorescence intensity and stability of organic fluorescent dyes are poor, and they are prone to photobleaching under long-term illumination. 2. Rare earth inorganic fluorescent materials: Its advantages are strong absorption capacity, high conversion rate, narrow-band emission of the central ion of rare earth complexes, which is conducive to full-color display, and stable physical and chemical properties. However, rare earth elements are relatively expensive, which may lead to high material costs, and the preparation process of rare earth luminescent nanomaterials is relatively complicated. 3. Quantum dot fluorescent dyes: Quantum dots have a wide excitation spectrum and a narrow emission spectrum, and their fluorescence intensity is higher than that of commonly used organic fluorescent materials. However, most quantum dots contain heavy metal elements (such as Cd, Pb, etc.), which may release free heavy metal ions, which are toxic to cells and biological tissues. In addition, the electric field confinement method has the highest cost and 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, and are ideal substitutes for traditional fluorescent materials. However, although copper-iodine cluster materials have shown great application potential, the practical application of such materials remains a challenge. At present, the 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 are difficult to process; they have no glass transition temperature, cannot be melted, and cannot be thermoformed like polymer materials, which greatly restricts their application in industry.

[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 the field and found that one or more of the above-mentioned 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 comprises: mixing CuI with acetonitrile to obtain a mixed solution; dropping 4-benzylpyridine into the mixed solution with 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 comprises: mixing CuI with acetonitrile to obtain a mixed solution; dropping 4-tert-butylpyridine 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 an aqueous sodium alginate 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 an aqueous calcium chloride 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, i.e., 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 in 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, and the change is reversible, with high luminous efficiency and good stability. The preparation process is simple, environmentally friendly, with high yield and low cost, and can realize the fluorescent diversified 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 copper-iodine cluster-based thermochromic fluorescent fiber obtained in Example 1 showed an XRD pattern with copper-iodine cluster powder Cu4I4(4-benzylpyridine)4, and the copper-iodine cluster-based thermochromic fluorescent fiber obtained in Example 4 showed an XRD pattern with copper-iodine cluster powder Cu4I4(4-tert-butylpyridine)4;

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

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

[0025] Figure 6 This is a 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 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), in high humidity (70% RH), immersed in water at room temperature, at 50°C, 85°C and under ultraviolet irradiation (300K);

[0028] Fig. 9 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 4 when stored in ambient air (20°C-35°C and 30%-40% RH), in high humidity (70% RH), immersed in water at room temperature, at 50°C, 85°C and under ultraviolet irradiation (300K);

[0029] Fig.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] Fig.11 The fluorescence color development photographs 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] Fig.12PL intensity comparison diagram 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] Fig.13 This is a color development photo of copper iodine cluster powder Cu4I4(4-benzylpyridine)4 under ultraviolet light and 300K;

[0033] Fig.14 This is a color development photo of copper iodine cluster powder Cu4I4(4-tert-butylpyridine)4 under ultraviolet light and 300K;

[0034] Fig.15 The color development photos of the spinning solution obtained in Example 1 under natural light, UV light and 300K;.

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

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

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

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

[0039] Fig. 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 content will be further elaborated according to specific embodiments. However, the specific embodiments listed are only for illustrative purposes and are not intended to limit the scope of the present 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, in which the Cu-Cu bonds in the cluster center of the Cu4I4 (4-benzylpyridine) 4 copper iodine cluster shrink as the temperature decreases, resulting in an emission peak in the high energy region (blue light band), which appears as white light after mixing with the original yellow light. 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 emission 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 3 CC emission, and partial halide-metal charge transfer ( 3 XMCT) process is the luminescence of the cluster core electron transition, which is independent of the ligand. However, at low temperature, it manifests as halide-pyridine ligand charge transfer ( 3 XLCT) process. 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 CC) is more stable and the emission wavelength is red-shifted. Since the room temperature-low temperature luminescence color change of the material does not involve phase change, the observed thermoluminescence color change is completely reversible. The calcium alginate polymer base combined with the copper iodine cluster compound can play a good protective role and will not cause a significant loss of its emission intensity, so that the copper iodine cluster-based thermochromic fiber can show color change under ultraviolet light in the temperature range of 80K-300K, and the change is reversible, has high luminous efficiency and good stability.

[0043] In some embodiments of the present application, the mass ratio of the calcium alginate to the copper-iodine cluster is 20-200:1, such as 20:1, 50:1, 70:1, 90:1, 100:1, 120:1, 150:1, 170:1, 200:1, etc., or can be a range composed of any of the above values. Thus, by mixing the polymer fiber with the copper-iodine cluster according to 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; dropping 4-benzylpyridine 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; dropping 4-tert-butylpyridine 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, such as 160 μm, 165 μm, 170 μm, 175 μm or 180 μm, etc., or can be a range consisting of any of the above values. Therefore, the thermochromic fluorescent fiber of 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 an aqueous sodium alginate 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 an aqueous calcium chloride 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 in 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, and the change is reversible, with high and stable luminous efficiency. In addition, the preparation process is simple, environmentally friendly, with high yield and low cost, and can realize the fluorescent diversified 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, and then the spinning solution is extruded through a spinneret by a metering pump at a spinning speed of 0.5mL / min-3mL / min into a coagulation bath of a CaCl2 aqueous solution with a concentration of 3wt%-10wt%, and the spun fibers are collected on a drum after the coagulation bath, and finally washed with deionized water to remove excess CaCl2 attached to the fiber surface, and then the sample is 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 embodiments described below are exemplary and are only used to explain the present application, and should not be construed as limiting the present application. Where specific techniques or conditions are not specified in the embodiments, the techniques or conditions described in the literature in this area or the product specifications are used. The reagents or instruments used without specifying the manufacturer are all conventional products that can be obtained commercially.

[0052] Preparation method 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 with methanol 3 times. Finally, the white powder was dried in vacuum at 40 °C for 24 h to obtain Cu4I4 (4-benzylpyridine) 4.

[0054] Method for preparing 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 with methanol for 3 times. Finally, the obtained white powder was dried in vacuum 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, and then the spinning solution is 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%, and the spun fibers are collected on a drum after the coagulation bath (drawing ratio is 1.5:1), and finally washed with deionized water to remove excess CaCl2 attached to the fiber surface, and then the sample is 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, and then the spinning solution is 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%, and the spun fibers are collected on a drum after the coagulation bath (drawing ratio is 1.5:1), and finally washed with deionized water to remove excess CaCl2 attached to the fiber surface, and then the sample is washed and dried at room temperature to obtain a copper iodine cluster-based thermochromic fluorescent fiber 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, and then the spinning solution is 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%, and the spun fibers are collected on a drum after the coagulation bath (drawing ratio is 1.5:1), and finally washed with deionized water to remove excess CaCl2 attached to the fiber surface, and then the sample is 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 and water are mixed 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 (drawing ratio is 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 and water are mixed 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 into a coagulation bath of a CaCl2 aqueous solution with a concentration of 5wt% through a spinneret by a metering pump at a spinning speed of 1mL / min. After the coagulation bath, the spun fibers are collected on a drum (drawing ratio is 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 and water are mixed 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 into a coagulation bath of a CaCl2 aqueous solution with a concentration of 5wt% through a spinneret by a metering pump at a spinning speed of 1mL / min. After the coagulation bath, the spun fibers are collected on a drum (the draft ratio is 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 fiber was 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. At 300K, 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. Among them, 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 as follows: 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 thermochromic fluorescent fiber obtained in Example 1 are as follows: Figure 6 As shown, 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 It can be seen that the emission wavelengths of the copper-iodine cluster-based thermochromic fluorescent fibers obtained in Examples 1 and 4 are 577 nm and 642 nm, respectively, and their fluorescent colors are yellow and orange, respectively. This shows 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 clusters can correspond well, indicating that the copper-iodine clusters can 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 respectively the stability curves of the copper iodine cluster thermochromic fluorescent fiber and the copper iodine cluster powder Cu4I4(4-benzylpyridine)4 obtained in Example 1 stored in ambient air (20°C-35°C and 30%-40% RH), in high humidity (70% RH), immersed in normal temperature water, at 50°C, 85°C and under ultraviolet irradiation (300K), wherein Fig. 9 a, b, c, d, e and F are respectively 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), Figure 8 a, b and c and Fig. 9 From a, b and c, it can be seen that 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 are 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 fiber obtained from Example 1 and Example 4 remains stable (>98%) and is higher than that of the corresponding copper iodine cluster powder, indicating that the copper iodine cluster-based thermochromic fluorescent fiber obtained from Example 1 and Example 4 has outstanding stability to high humidity, water and oxygen. Figure 8 In d and e and Fig. 9 As shown in 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 Fig. 9 It can be seen from the figure 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-based thermochromic fluorescent fiber of Example 1 and the corresponding copper-iodine cluster powder Cu4I4(4-benzylpyridine)4 were immersed in ethanol, hexane, acetone, N,N-dimethylformamide (DMF) and toluene organic solvents for 5 h, and then subjected to fluorescence irradiation at 300 K. Fig.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 Fig.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 the fluorescent properties in ethanol, n-hexane, acetone, N, N-dimethylformamide (DMF) and toluene organic solvents. Fig.12 The PL intensity change of the copper-iodine cluster-based thermochromic fluorescent fiber in Example 1 can also be ignored, which indicates 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 base may protect the copper-iodine cluster powder.

[0080] 6. The copper iodine cluster powder Cu4I4(4-benzylpyridine)4 and the 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. Fig.13 This is a photo of copper iodine cluster powder Cu4I4(4-benzylpyridine)4 under ultraviolet light and 300K, which appears yellow. Fig.14 This is a photo of copper iodine cluster powder Cu4I4(4-tert-butylpyridine)4 under ultraviolet light and 300K, which appears orange; Fig.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 maintained under natural light, but yellow fluorescence is displayed under ultraviolet light; Fig.16 The spinning solution obtained in Example 4 is photographed under natural light, ultraviolet light and 300K. The original color of the fiber is maintained under natural light, while it shows orange fluorescence under ultraviolet light; Fig.17 The copper-iodine cluster-based thermochromic fluorescent fiber obtained in Example 1 is photographed under natural light, under ultraviolet light, and at 300K. The fiber retains its original color under natural light, but shows yellow fluorescence under ultraviolet light; Fig.18 These are photos of the copper iodine cluster-based thermochromic fluorescent fiber obtained in Example 4 under natural light, under ultraviolet light, and at 300K. The fiber retains its original color under natural light, but displays orange fluorescence under ultraviolet light.

[0081] Fig.19The copper iodine cluster-based thermofluorescent fiber obtained in Example 1 is white at 80K and 300K and under ultraviolet light. It is white at 80K, and when the temperature is increased to 300K, it is yellow under ultraviolet light, and after the temperature is reduced 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 the temperature range of 80K-300K, and the color change process is reversible. The copper iodine cluster-based thermofluorescent fiber obtained in Examples 2 and 3 is white under ultraviolet light and 80K, and when the temperature is increased to 300K, it is yellow under ultraviolet light, and after the temperature is reduced 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 the temperature range of 80K-300K, and the color change process is reversible.

[0082] Fig. 20 The copper iodine cluster-based thermofluorescent fiber obtained in Example 4 is purple at 80K and 300K and under ultraviolet light. It is purple at 80K, and when the temperature is increased to 300K, it is orange under ultraviolet light, and after the temperature is reduced 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 the temperature range of 80K-300K, and the color change process is reversible. The copper iodine cluster-based thermofluorescent fiber obtained in Examples 5 and 6 is purple under ultraviolet light and 80K, and when the temperature is increased to 300K, it is orange under ultraviolet light, and after the temperature is reduced 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 the temperature range of 80K-300K, and the color change process is reversible.

[0083] The above is only a specific implementation of the invention covered by this application, but the protection scope of this application is not limited thereto. Any technician familiar with the technical field can easily think of changes or substitutions within the technical scope disclosed in this application, which should be included in the protection scope of this application. Therefore, the protection scope of this application should be based on the protection scope of the claims.

Claims

1. A copper-iodine cluster-based thermochromic fluorescent fiber, characterized in that: include: Calcium alginate and copper iodine clusters, wherein the copper iodine clusters include 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 dropped into the mixed solution to form a white precipitate; The white precipitate was isolated, then 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 dropped into the mixed solution to form a white precipitate; The white precipitate was isolated, then 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; The copper-iodine cluster-based thermochromic fluorescent fibers were obtained by wet spinning with 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 according to 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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