Water-based nano fluorescent microsphere, fluorescent silk yarn and preparation method and application of water-based nano fluorescent microsphere and fluorescent silk yarn

Abstract

The invention belongs to the technical field of functional textiles, and particularly discloses water-based nano fluorescent microspheres, fluorescent silk yarn and a preparation method and application of the water-based nano fluorescent microspheres and the fluorescent silk yarn. The water-based nano fluorescent microspheres are prepared by adopting an ultrasonication microemulsion polymerization method, then the nano microspheres are arranged on the silk by utilizing a layer-by-layer self-assembly technology to prepare the fluorescent yarns, and the textile anti-counterfeiting is realized in a sewing and embroidering manner. The prepared nano fluorescent microspheres are uniform in particle size distribution, the particle size range is 30-300 nm, and the relative fluorescence intensity of the fluorescent silk yarn reaches up to 8500 or above. The prepared fluorescent silk yarn shows a fluorescent effect under ultraviolet irradiation, can still maintain the original fluorescence intensity after being washed with water for 30 minutes and rubbed for 400 times, and has good wearability. And each yarn has a unique mark or characteristic, is difficult to counterfeit or tamper, and has a wide application prospect in the fields of labels of textiles and anti-counterfeiting identification.

Description

Technical Field

[0001] This invention belongs to the field of functional textile technology, specifically relating to an aqueous fluorescent nanosphere, fluorescent silk yarn, its preparation method and application. Background Technology

[0002] Optical anti-counterfeiting features high visibility, diverse colors, and simple design. Fluorescent anti-counterfeiting, in particular, possesses strong concealment and is often considered the most ideal anti-counterfeiting technology. Fluorescent microspheres, as a special type of functional microsphere, are widely used in the textile anti-counterfeiting industry due to their stable morphology, narrow particle size distribution, good monodispersity, and high luminescence efficiency. Currently, methods for preparing polystyrene microspheres include emulsion polymerization, dispersion polymerization, suspension polymerization, and seed polymerization. Dispersion polymerization has the advantages of simple operation and a wide range of monomer and solvent choices; however, it is prone to introducing cross-linking agents during the polymerization reaction, resulting in highly cross-linked microspheres. Because highly cross-linked cores do not easily absorb monomers and cross-linking agents, polymerization mainly occurs on the surface of the core, easily leading to cross-linking between microspheres and uneven particle size. Therefore, preparing monodisperse polystyrene microspheres with uniform particle size through dispersion polymerization remains a technical challenge.

[0003] As a fundamental building block of textiles, yarn possesses unique advantages as an anti-counterfeiting carrier. It can achieve anti-counterfeiting purposes during the spinning or post-processing stages through methods such as magnetic particles, fluorescent substances, and nano-coding. Each fluorescent yarn has a unique mark and characteristic, making it difficult to imitate or tamper with. Anti-counterfeiting labels made from fluorescent yarn can effectively prevent product counterfeiting and imitation. Therefore, fluorescent yarn anti-counterfeiting has attracted much attention in the field of textile anti-counterfeiting due to its high concealment, high recognizability, and non-removability.

[0004] Therefore, how to provide an aqueous fluorescent nanosphere with sustained fluorescence intensity variation and monodispersity is a topic worthy of research. Summary of the Invention

[0005] The purpose of this invention is to address the shortcomings of existing technologies by providing an aqueous fluorescent nanosphere, fluorescent silk yarn, its preparation method, and its applications. The fluorescent nanospheres prepared via microemulsion polymerization have a particle size distribution between 30 and 300 nm and exhibit high relative fluorescence intensity. Furthermore, this method transforms a multi-step process into a one-step process, allowing fluorescent molecules to bond into the polymer microspheres, preventing loss and avoiding the leakage of fluorescein dyes from the fluorescent polymer microspheres, as well as the need for subsequent encapsulation and functional modification steps. Finally, layer self-assembly technology is used to coat the nanoscale fluorescent microspheres onto the surface of modified silk yarn to prepare fluorescent yarn, which is then applied to fabric anti-counterfeiting and information encryption.

[0006] To achieve the above objectives, the present invention adopts the following technical solution: The first objective of this invention is to provide a method for preparing aqueous fluorescent nanospheres, which employs an ultrasonic disruption microemulsion polymerization method and includes the following steps: S1. Organic phase preparation: Modifier and stabilizer are added to styrene solution and mixed thoroughly, then fluorescent dye is added and mixed to obtain organic phase; S2. Preparation of water-based solution: Disperse the surfactant in deionized water to obtain a water-based solution; S3. Slowly pour the organic phase solution from step S1 into the water-based solution from step S2, and then ultrasonically break down and emulsify it under ice bath conditions. S4. After ultrasonic disruption and emulsification, the reaction system is deoxygenated by passing nitrogen gas through it. After heating, an initiator is added, and the mixture is stirred and heated further. The reaction is carried out under nitrogen protection to prepare nanopolymer microspheres by microemulsion polymerization. After dialysis treatment, aqueous fluorescent nanospheres are obtained.

[0007] Furthermore, the fluorescent dye includes any one or more of anthocyanins, rhodamine B, rhodamine 6G, 7-hydroxycoumarin, fluorescein isothiocyanate, and tetramethylrhodamine-5-isothiocyanate.

[0008] Furthermore, the modifier includes one or more of acrylic acid, sulfonic acid, amide, and ammonia.

[0009] Furthermore, the stabilizer includes one or more of polyvinylpyrrolidone, hexadecane, and polycarboxylate.

[0010] Furthermore, the surfactant includes one or more of sodium hexadecyl sulfate, octadecyltrimethylammonium bromide, fatty acid monoglycerides, glyceryl monostearate, and sodium polyacrylamide cresol sulfonate.

[0011] Furthermore, the initiator includes any one or more of azobisisobutyranin hydrochloride, potassium persulfate, terpentyl hydroperoxide, azobisisobutyronitrile, and azobisisobutyramidoline hydrochloride.

[0012] Further, in step S1, the volume-to-mass ratio of the modifier, stabilizer, phenylacetic acid and fluorescent dye is (1~7) μL: 10 mg: 200 mg: 2 mg.

[0013] Furthermore, in step S2, the mass concentration of the water-based solution is 1.55~4.8 mg / mL.

[0014] Furthermore, in step S3, the ultrasonic breaking power is 200~500 W, and the ultrasonic breaking time is 1~8 min.

[0015] Further, in step S4, the mass ratio of the initiator added to phenylacetic acid is (5-30):10, the temperature at which the initiator is added is 50-60℃, the reaction temperature is 70-80℃, and the reaction time is 7-8 h.

[0016] A second objective of this invention is to provide an aqueous fluorescent nanosphere, which is prepared using the above-described preparation method.

[0017] The third objective of this invention is to provide a fluorescent silk yarn, which is prepared by modifying the silk yarn with cationic monomers and then loading the aforementioned aqueous fluorescent nanospheres onto the surface of the silk yarn through an electrostatic self-assembly method.

[0018] The fourth objective of this invention is to provide a fluorescent silk yarn, wherein the cationic monomer is one or more of octadecyl dimethyl benzyl ammonium chloride, hexadecyl trimethyl ammonium chloride, and polyethyleneimine.

[0019] The fifth objective of this invention is to provide an application of fluorescent silk yarn in the preparation of anti-counterfeiting labels.

[0020] Compared with the prior art, the beneficial effects of the present invention are: (1) This invention discloses an aqueous fluorescent nanosphere, which is prepared by ultrasonic microemulsion polymerization. This method utilizes the cavitation effect of ultrasound to achieve efficient emulsification at room temperature and pressure, allowing immiscible liquids to mix instantly and uniformly, thereby achieving uniform dispersion of the reaction system. During the reaction, a polymerizable hydrophilic monomer modifier is introduced. Fluorescein molecules are chemically bonded to styrene and the modifier. This chemical bonding not only makes the binding of fluorescein molecules to the microspheres stronger, but also improves the fluorescence stability and relative fluorescence intensity of the fluorescent microspheres. The prepared fluorescent nanospheres have a uniform particle size distribution, ranging from 30 to 300 nm, and exhibit strong fluorescence under 365 nm ultraviolet light irradiation.

[0021] (2) Fluorescent anti-counterfeiting yarn was prepared by coating the surface of modified silk thread with nano-fluorescent microspheres using layer-by-layer self-assembly technology. First, the silk fibers were chemically modified with cationic monomers to make their surface positively charged. Then, fluorescent microspheres were uniformly adsorbed and fixed onto the silk surface through electrostatic adsorption to prepare fluorescent silk yarn. The relative fluorescence intensity of the prepared fluorescent silk yarn was as high as 8500 or more. The anti-counterfeiting labels prepared by sewing and embroidery showed a fluorescent effect under ultraviolet light. After 30 minutes of washing and 400 rubs, the fluorescent silk yarn could still maintain its original fluorescence intensity, which has a good effect of fluorescent anti-counterfeiting and information encryption.

[0022] (3) The method for preparing aqueous fluorescent nanospheres provided by this invention avoids the pollution and side effects that emulsifiers may cause because it does not require the addition of chemical emulsifiers. At the same time, the efficient emulsification ability of ultrasound greatly shortens the reaction time and improves production efficiency.

[0023] (4) The anti-counterfeiting design of nanotechnology and traditional process provided by the present invention not only improves the functionality of textiles, but also provides new possibilities for their application in high-end anti-counterfeiting, personalized customization and artistic decoration. Attached Figure Description

[0024] Figure 1 Excitation and emission spectra of three different fluorescent dyes with varying acrylic acid content; Figure 2 This is a particle size distribution diagram of the fluorescent nanospheres synthesized in Example 4; Figure 3 The particle size distribution diagram is shown for the fluorescent nanospheres synthesized in Example 5. Figure 4 The particle size distribution diagram is shown for the fluorescent nanospheres synthesized in Example 6. Figure 5 Excitation and emission spectra of three different fluorescent dyes with different SDS contents; Figure 6 Figure 1 shows the stability test results of fluorescence performance of three types of fluorescent microspheres at different temperatures and pH values. Figure 7 Digital photographs of the aqueous solutions of the fluorescent nanospheres synthesized in Examples 1-3 under visible light and 365 nm ultraviolet light irradiation. Figure 8 Digital photographs of the fluorescent silk yarns synthesized in Examples 10-12 under visible light and 365 nm ultraviolet light irradiation; Figure 9 Digital photographs of embroidery patterns prepared from the fluorescent silk yarns synthesized in Examples 10-12 under visible light and 365 nm ultraviolet light irradiation. Figure 10 The abrasion resistance and washability of the fluorescent silk yarns synthesized in Examples 10-12 are shown. Detailed Implementation

[0025] To make the objectives, technical solutions, and advantages of this invention clearer, the specific embodiments and accompanying drawings are described in further detail below. Where specific techniques or conditions are not specified in the embodiments, they are performed according to the techniques or conditions described in the literature in this field or according to the product instructions. Reagents or instruments whose manufacturers are not specified are all commercially available conventional products.

[0026] This invention provides a method for preparing aqueous fluorescent nanospheres and fluorescent silk yarn, which are prepared from raw materials comprising the following proportions: Styrene, fluorescein dye, modifier, stabilizer, surfactant, initiator, cationic monomer and water; In this invention, the fluorescein dye is preferably one or more of anthocyanin, rhodamine B, rhodamine 6G, 7-hydroxycoumarin, fluorescein isothiocyanate, and tetramethylrhodamine-5-isothiocyanate.

[0027] In this invention, the modifier is preferably one or more of acrylic acid, sulfonic acid, amide, and ammonia.

[0028] In this invention, the stabilizer is preferably one or more of polyvinylpyrrolidone, hexadecane, and polycarboxylate.

[0029] In this invention, the surfactant is preferably one or more of sodium hexadecyl sulfate, octadecyltrimethylammonium bromide, fatty acid monoglyceride, glyceryl monostearate, and sodium polyacrylamide cresol sulfonate.

[0030] In this invention, the initiator is preferably one or more of azobisisobutyranin hydrochloride, potassium persulfate, terpentyl hydroperoxide, azobisisobutyronitrile, and azobisisobutyramidoline hydrochloride.

[0031] In this invention, the cationic modified monomer is preferably one or more of octadecyl dimethyl benzyl ammonium chloride, hexadecyl trimethyl ammonium chloride, and methacryloyloxyethyl trimethyl ammonium chloride.

[0032] The specific steps are as follows: (1) First, the stabilizer and styrene are initially mixed, and then the fluorescein dye and modifier are added and sonicated to obtain an organic phase solution; (2) Disperse the surfactant in deionized water and sonicate it to obtain an aqueous solution; (3) Slowly pour the organic phase solution into the water-based solution, and break and emulsify the mixed solution in an ultrasonic cell disruptor by the cavitation effect of ultrasound. (4) After ultrasonic emulsification, nitrogen gas is passed through the reaction system for deoxygenation treatment. After heating, an initiator is added, and the mixture is stirred and heated further. The reaction is carried out under nitrogen protection to prepare nanopolymer microspheres by microemulsion polymerization.

[0033] (5) The prepared polymer solution was dialyzed in a mixed solution of ethanol and deionized water to obtain aqueous fluorescent nanospheres.

[0034] (6) The silk yarn is modified with cationic monomers, and then the aqueous fluorescent nanospheres obtained in step (5) are loaded onto the surface of the silk yarn to prepare fluorescent yarn by electrostatic self-assembly.

[0035] In this invention, the frequency of the preliminary ultrasound in step (1) is preferably 28~40 kHz, more preferably 30~38 kHz, and even more preferably 33~36 kHz; the time is preferably 5~15 min, more preferably 7~13 min, and even more preferably 8~10 min; In this invention, the frequency of the ultrasound in step (2) is preferably 30~38 kHz, more preferably 32~36 kHz, and even more preferably 33~35 kHz; the time is preferably 10~20 min, more preferably 12~18 min, and even more preferably 13~15 min.

[0036] In this invention, the ultrasonic cell disruptor in step (3) has a disruption power of 200~500 W, more preferably 250~450 W, and even more preferably 300~400 W; the ultrasonic disruption time is preferably 1~8 min, more preferably 3~6 min, and even more preferably 4~5 min.

[0037] In this invention, the reaction in step (4) is carried out in an oil bath. The temperature of the reaction is preferably 65~75 ℃, more preferably 67~73 ℃, and even more preferably 68~70 ℃. The rotation speed of the reaction is preferably 200~400 r / min, more preferably 220~350 r / min, and even more preferably 260~300 r / min. The reaction time is preferably 7~9 h, more preferably 7.5~8.5 h, and even more preferably 8~8.2 h.

[0038] In this invention, the proportion of ethanol solution in step (5) is preferably 5% to 30%, more preferably 10% to 25%, and even more preferably 15% to 20%; the dialysis time is preferably 3 to 10 days, more preferably 5 to 8 days, and even more preferably 6 to 7 days.

[0039] In this invention, the concentration of the cationic monomer solution in step (6) is preferably 1% to 10%, more preferably 3% to 8%, and even more preferably 5% to 6%.

[0040] In this invention, the fluorescent nanospheres are stored at room temperature away from light.

[0041] The aqueous fluorescent nanospheres and fluorescent silk yarns prepared by the method provided in this invention have similar structures and properties.

[0042] The embodiments of the present invention have achieved some positive results during the research and development or use process, and have indeed great advantages compared with the prior art. The following content describes them in conjunction with the data, charts and other information of the experimental process.

[0043] The characterization and testing methods used in the embodiments of this invention are as follows: Fluorescence spectrophotometer (FL): Using an F-2500 fluorescence spectrophotometer, the excitation and emission spectra of fluorescent microspheres were measured by dissolving them in deionized water at room temperature.

[0044] Zeta potential test: The zeta potential of the sample was tested using a ZS-90 laser particle size analyzer (Malvin Instruments, Inc., USA).

[0045] Particle size and dispersion coefficient: The particle size and dispersion coefficient of the synthesized samples were tested using a potentiometer and particle size analyzer. Each sample solution was measured three times and the average value was taken as the final particle size and dispersion coefficient.

[0046] Air permeability test: The air permeability of fluorescent fabrics was tested using a digital air permeability meter according to GB / T 5453-1997 standard. The test principle is as follows: air is passed vertically through the fluorescent fabric, creating a certain pressure difference between its front and back sides. The air permeability of the fluorescent fabric is determined by measuring the amount of air that passes through the fabric per unit time under a specific pressure difference.

[0047] Abrasion resistance test: The abrasion resistance test was conducted using a fabric abrasion tester. The fluorescent fabric was rubbed according to GB / T 21196.4—2007 Textiles, Martindale Method for Determination of Abrasion Resistance of Fabrics Part 4: Evaluation of Appearance Changes. The weight used was 200 g. After every 50 abrasions, the change in relative fluorescence intensity of the fabric was measured to characterize the abrasion resistance of the fabric.

[0048] Wash resistance test: The fluorescent fabric was placed in 100 mL of deionized water and stirred 10 times at 800 r / min for 5 min each time. The change in relative fluorescence intensity of the fluorescent fabric after washing was measured using a fluorescence spectrophotometer to characterize the wash resistance of the fluorescent fabric.

[0049] Example 1 This embodiment provides an aqueous fluorescent nanosphere and its preparation method.

[0050] S1. Weigh 8 g of styrene solution into a 50 mL beaker, then add 0.4 g of hexadecane, 80 mg of RhB, and 220 μL of acrylic acid in sequence, and sonicate at 33 kHz for 15 min to mix thoroughly into an organic phase; S2. Weigh 480 mg of sodium dodecyl sulfate into a 100 mL beaker, add 40 mL of deionized water, and sonicate at 33 kHz for 10 min to make it uniformly mixed into an aqueous solution. S3. Slowly add the organic phase solution to the water-based solution. Under ice bath conditions, use the cavitation effect of ultrasound to ultrasonically break up the mixed solution for 5 minutes (2 s on, 2 s off, power 350 W) using an ultrasonic cell disruptor. This can effectively break up small droplets in the mixed solution to form an emulsion and promote the mixing and diffusion between reactants.

[0051] S4. Pour the mixed solution into a three-necked flask, purge with nitrogen for 30 min for deoxygenation, heat to 50 °C in an oil bath, add 160 mg of azobisisobutyronitrile (AIBN), and finally react at 70 °C for 8 h.

[0052] S5. The obtained emulsion was dialyzed and washed for 7 days with a mixed solution of ethanol and deionized water (15% ethanol) until excess impurities were removed, resulting in a pink emulsion. After drying, it was stored at room temperature away from light to obtain aqueous fluorescent nanospheres.

[0053] Example 2 It is basically the same as Example 1, except that it contains fluorescein isothiocyanate (FITC).

[0054] Example 3 This is essentially the same as Example 1, except that it uses fluorescein 7-hydroxycoumarin (7HC). Example 4 The effect of different acrylic acid contents on water-based fluorescent nanospheres was investigated.

[0055] The experiment was basically the same as in Example 1, except that different amounts of acrylic acid were added (40 μL, 100 μL, 160 μL, 220 μL, 280 μL).

[0056] Example 5 The effect of different acrylic acid contents on water-based fluorescent nanospheres was investigated.

[0057] The experiment was basically the same as in Example 2, except that different amounts of acrylic acid were added (40 μL, 100 μL, 160 μL, 220 μL, 280 μL).

[0058] Example 6 The effect of different acrylic acid contents on water-based fluorescent nanospheres was investigated.

[0059] The experiment was essentially the same as in Example 3, except that different amounts of acrylic acid were added (40 μL, 100 μL, 160 μL, 220 μL, 280 μL). Example 7 The effect of different sodium dodecyl sulfate (SDS) contents on aqueous fluorescent nanospheres was investigated.

[0060] The experiment was basically the same as in Example 1, except that different amounts of sodium dodecyl sulfate (115 mg, 160 mg, 320 mg, 480 mg) were added.

[0061] Example 8 The effect of different sodium dodecyl sulfate (SDS) contents on aqueous fluorescent nanospheres was investigated.

[0062] The experiment was basically the same as in Example 2, except that different amounts of sodium dodecyl sulfate (115 mg, 160 mg, 320 mg, 480 mg) were added.

[0063] Example 9 The effect of different sodium dodecyl sulfate (SDS) contents on aqueous fluorescent nanospheres was investigated.

[0064] The experiment was basically the same as in Example 3, except that different amounts of sodium dodecyl sulfate (115 mg, 160 mg, 320 mg, 480 mg) were added.

[0065] Performance studies were conducted on Examples 1-9, and the details are as follows: 1. The effect of different acrylic acid contents on water-based fluorescent nanospheres.

[0066] (1) Relative fluorescence intensity Depend on Figure 1 It can be seen that the relative fluorescence intensity of the aqueous fluorescent nanospheres increases with the increase of acrylic acid content. When the acrylic acid content is 280 μL, the relative fluorescence intensity of Example 1 is 9609, the relative fluorescence intensity of Example 2 is 8636, and the relative fluorescence intensity of Example 3 is 9620.

[0067] The relative fluorescence intensity of aqueous fluorescent nanospheres increased with increasing acrylic acid content. This may be because the addition of acrylic acid alters the molecular structure of the microspheres, leading to carboxylation on the surface of the fluorescent microspheres. These carboxyl groups can form stable chemical bonds with RhB, FITC, and 7HC dye molecules, making the interaction between the microspheres and the fluorescent groups more robust and reducing fluorescence quenching. Simultaneously, increasing the amount of acrylic acid may also affect the particle size and monodispersity of the microspheres; a more uniform particle size distribution helps improve fluorescence efficiency.

[0068] (2) Particle size Depend on Figure 2It can be seen that the particle size of the aqueous nanospheres prepared in Example 1 is 87.1 nm. With the increase of acrylic acid content, the average particle size of the fluorescent microspheres prepared in Example 4 decreases. The average particle size with 40 μL of acrylic acid is 110.1 nm, and the PDI is 0.024; the average particle size with 100 μL of acrylic acid is 108.2 nm, and the PDI is 0.056; the average particle size with 160 μL of acrylic acid is 108.5 nm, and the PDI is 0.038; the average particle size with 220 μL of acrylic acid is 87.1 nm, and the PDI is 0.038; the average particle size with 280 μL of acrylic acid is 83.1 nm, and the PDI is 0.057. The fluorescent microspheres exhibit the best dispersibility when the acrylic acid content is 160 μL. The PDI values ​​are all less than 0.1, indicating that the prepared aqueous fluorescent nanospheres have extremely high uniformity and monodispersity, are not prone to aggregation, and possess extremely high stability.

[0069] This phenomenon is likely closely related to the role of acrylic acid in the polymerization process. The introduction of acrylic acid alters the molecular structure and chain segment flexibility of the polymer, thereby affecting the microsphere formation mechanism. The carboxyl functional groups of acrylic acid may promote uniform dispersion of microspheres and reduce particle aggregation through interaction with the polymer chains, leading to a reduction in particle size. Furthermore, the reduction in particle size may also be related to the cross-linking effect of acrylic acid on the polymer chains, which makes the microsphere structure more compact. This reduction in particle size not only helps improve the dispersibility and stability of microspheres but may also enhance their performance in biomedical and chemical analysis applications.

[0070] Depend on Figure 3 It can be seen that the particle size of the aqueous nanospheres prepared in Example 2 is 80.5 nm. With the increase of acrylic acid content, the particle size of the aqueous fluorescent nanospheres prepared in Example 5 remains basically unchanged, maintaining a stable trend. The average particle size with 40 μL of acrylic acid added is 81 nm, and the PDI is 0.050; the average particle size with 100 μL of acrylic acid added is 76.0 nm, and the PDI is 0.076; the average particle size with 160 μL of acrylic acid added is 81.8 nm, and the PDI is 0.036; the average particle size with 220 μL of acrylic acid added is 80.5 nm, and the PDI is 0.046; the average particle size with 280 μL of acrylic acid added is 75.1 nm, and the PDI is 0.090. The fluorescent microspheres exhibit the best dispersibility when the acrylic acid content is 160 μL.

[0071] This is likely because during the microsphere nucleation stage, the FITC fluorescent dye is primarily embedded within the microspheres, while the addition of acrylic acid causes carboxylation on the microsphere surface, which does not affect the microsphere size. Therefore, in large-scale synthesis, it is possible to produce compliant products using less acrylic acid.

[0072] Depend on Figure 4 It can be seen that the particle size of the aqueous nanospheres prepared in Example 3 is 79.5 nm. With increasing amounts of acrylic acid, the aqueous fluorescent nanospheres prepared in Example 6 exhibit good particle size stability. The average particle size with 40 μL of acrylic acid added is 85.9 nm, and the PDI is 0.054; the average particle size with 100 μL of acrylic acid added is 85.2 nm, and the PDI is 0.035; the average particle size with 160 μL of acrylic acid added is 109.1 nm, and the PDI is 0.096; the average particle size with 220 μL of acrylic acid added is 79.5 nm, and the PDI is 0.052; and the average particle size with 280 μL of acrylic acid added is 80 nm, and the PDI is 0.059. Even with increased acrylic acid content, the particle size of the microspheres remains stable, possibly because the dispersant and reaction conditions in the polymerization system play a dominant role in regulating the particle size.

[0073] 2. Effect of different sodium dodecyl sulfate (SDS) contents on aqueous fluorescent nanospheres (1) Relative fluorescence intensity study When the SDS content was 115 mg, the relative fluorescence intensity of Example 1 was 7596, that of Example 2 was 7808, and that of Example 3 was 8574. As the SDS content increased, the relative fluorescence intensity of the fluorescent microspheres continuously increased. When the SDS content was 480 mg, the relative fluorescence intensity of Example 1 increased to 8856, that of Example 2 was 8737, and that of Example 3 was 9636.

[0074] With increasing SDS content, the relative fluorescence intensity of the microspheres showed a significant upward trend. This is because SDS can reduce the interfacial tension between the aqueous and oil phases, forming a uniform and stable emulsion, providing a good dispersion environment for the formation of polystyrene microspheres. As the SDS content increases, the stability of the emulsion improves, allowing fluorescent dye molecules to be more uniformly dispersed in the polymer matrix, thereby increasing the relative fluorescence intensity of the fluorescent microspheres. In addition, increasing the SDS content not only contributes to emulsion stability but may also affect the encapsulation efficiency of the fluorescent dye. During polymerization, the micelle structure formed by SDS can effectively encapsulate fluorescent dye molecules, preventing their aggregation or leakage during the reaction. This encapsulation effect allows the fluorescent dye molecules to exist more stably inside the polystyrene microspheres, thus improving the fluorescence intensity of the microspheres.

[0075] (2) Particle size study The particle sizes of the aqueous fluorescent nanospheres prepared in Example 7 are as follows: the average particle size with 115 mg SDS is 122.7 nm and the PDI is 0.038; the average particle size with 160 mg SDS is 108.5 nm and the PDI is 0.037; the average particle size with 320 mg SDS is 100.2 nm and the PDI is 0.030; and the average particle size with 480 mg SDS is 80.1 nm and the PDI is 0.024.

[0076] The particle sizes of the aqueous fluorescent nanospheres prepared in Example 8 are as follows: the average particle size with 115 mg SDS is 172.7 nm and the PDI is 0.050; the average particle size with 160 mg SDS is 119.1 nm and the PDI is 0.046; the average particle size with 320 mg SDS is 106.1 nm and the PDI is 0.033; and the average particle size with 480 mg SDS is 83.5 nm and the PDI is 0.028.

[0077] The particle sizes of the aqueous fluorescent nanospheres prepared in Example 9 are as follows: the average particle size with 115 mg SDS is 114.3 nm and the PDI is 0.122; the average particle size with 160 mg SDS is 112.7 nm and the PDI is 0.069; the average particle size with 320 mg SDS is 110.2 nm and the PDI is 0.096; and the average particle size with 480 mg SDS is 109.1 nm and the PDI is 0.096.

[0078] Increasing SDS content leads to smaller microsphere size because SDS can form micelle structures in the aqueous phase, which serve as tiny reaction sites for the polymerization reaction. As the SDS content increases, more micelles form, providing more nucleation sites for the growth of polymer microspheres. This results in smaller microsphere sizes in the initial formation stage, and the particle size growth is limited as the reaction progresses.

[0079] Secondly, the presence of SDS reduces the interfacial tension between the aqueous and oil phases, thereby improving the stability of the emulsion. This stability helps form more uniform emulsion droplets, resulting in more uniform particle size and smaller final fluorescent microspheres. Furthermore, after adsorption on the microsphere surface, SDS molecules form a charged layer. This charged layer prevents the aggregation of microspheres through electrostatic repulsion, further reducing the particle size.

[0080] (3) Study on fluorescence stability of aqueous fluorescent nanospheres To verify the stability of the fluorescent nanospheres, three different fluorescent microspheres (CPS / RhB, CPS / FITC, and CPS / 7HC) were prepared according to the method in Example 1, using 160 μL of acrylic acid and 480 mg of SDS, respectively. The stability of their fluorescence properties was tested at different temperatures and pH values. The results are as follows: Figure 6 As shown.

[0081] Figure 6 (a) shows the change in relative fluorescence intensity of CPS / RhB at different temperatures. The initial relative fluorescence intensity of CPS / RhB was 8510. When the temperature increased to 90℃, the relative fluorescence intensity of CPS / RhB was 8421. Within a temperature range of 1–90℃, the relative fluorescence intensity of CPS / RhB remained almost unchanged, maintaining 98.95% of its initial relative fluorescence intensity. Figure 6 (b) shows the change in relative fluorescence intensity of CPS / FITC at different temperatures. The initial relative fluorescence intensity of CPS / FITC was 8445. When the temperature reached 90℃, the relative fluorescence intensity of CPS / FITC was 8252, showing a slight decrease to 97.71% of its initial relative fluorescence intensity. Figure 6(c) shows the change in relative fluorescence intensity of CPS / 7HC at different temperatures. The initial relative fluorescence intensity of CPS / 7HC was 8622, and the relative fluorescence intensity at 90 °C was 8598. Within a temperature range of 1–90 °C, the relative fluorescence intensity of CPS / 7HC remained almost unchanged. These results indicate that the three types of fluorescent microspheres prepared did not show significant attenuation or change in relative fluorescence intensity and spectral characteristics after long-term storage, demonstrating fluorescence stability. This characteristic not only lays a solid foundation for the widespread application of fluorescent microspheres in biomedical detection, materials science, and environmental monitoring, but also provides strong protection for their long-term storage and transportation, significantly improving the feasibility and economy of their practical applications.

[0082] Figure 6(d) shows the change in relative fluorescence intensity of CPS / RhB at different pH values. At pH 7, the relative fluorescence intensity of CPS / RhB is 8637. Under acidic conditions (pH 3–5), the relative fluorescence intensity of CPS / RhB remains almost unchanged. However, under alkaline conditions (pH 7–11), the relative fluorescence intensity of CPS / RhB decreases slightly. At pH 11, the relative fluorescence intensity decreases to 8286, which is 95.93% of the initial relative fluorescence intensity.

[0083] Figure 6 (e) shows the change in relative fluorescence intensity of CPS / FITC at different pH values. At pH 7, the relative fluorescence intensity of CPS / FITC is 8378. At pH 5, its relative fluorescence intensity hardly changes; however, at pH 3, the relative fluorescence intensity of CPS / FITC decreases to 8110, which is 96.80% of the initial relative fluorescence intensity. Under alkaline conditions with pH values ​​between 7 and 11, its relative fluorescence intensity decreases slightly; at pH 11, the relative fluorescence intensity of CPS / FITC is 8232, which is 98.26% of the initial relative fluorescence intensity. Under acidic conditions with pH values ​​between 3 and 5, the relative fluorescence intensity of CPS / FITC shows a slight decreasing trend.

[0084] Figure 6(f) shows the changes in the relative fluorescence intensity of CPS / 7HC at different pH values. When pH is 7, the relative fluorescence intensity of CPS / 7HC is 8580. When pH is 5, its relative fluorescence intensity is 8461; when pH is 3, its relative fluorescence intensity decreases to 7507, which is 87.49% of the initial relative fluorescence intensity. When pH is 9, the relative fluorescence intensity of CPS / 7HC is 8588; while when pH is 11, the relative fluorescence intensity of CPS / 7HC increases significantly to 8911.

[0085] The stability and applicability of three fluorescent microspheres, CPS / RhB, CPS / FITC, and CPS / 7HC, prepared by ultrasonic microemulsion disruption and encapsulation methods, were verified under various experimental conditions through high-temperature qualitative testing and fluorescence performance analysis under different pH conditions. They also demonstrated good fluorescence and environmental stability.

[0086] Example 10 This embodiment provides a fluorescent silk yarn and its preparation method.

[0087] Clean silk yarn was placed in a 100 mL beaker, and 40 mL of a 5% (w / w) polyethyleneimine (PEI) solution was added. After stirring for 30 min, 0.1 g of the fluorescent nanospheres prepared in Example 1 was accurately weighed into 40 mL of deionized water. Fluorescent silk yarn was prepared by loading the fluorescent nanospheres onto the silk using an electrostatic self-assembly method. The prepared fluorescent silk yarn exhibited a bright red fluorescence under 365 nm ultraviolet light irradiation.

[0088] Digital photographs of the nanoscale fluorescent microspheres used in this embodiment under visible light and 365 nm ultraviolet light are shown below. Figure 7 As shown, the microsphere solution appears pink under visible light and emits strong orange-red fluorescence under 365 nm ultraviolet light irradiation; the fluorescent silk yarn prepared in this embodiment is as follows. Figure 8 As shown, it exhibits obvious orange-red fluorescence under 365 nm ultraviolet light irradiation; the anti-counterfeiting label prepared from the fluorescent silk yarn in this example is as follows. Figure 9 As shown, it emits a bright red fluorescence under 365 nm ultraviolet light; the abrasion resistance and washability of the silk yarn prepared in this embodiment are as follows: Figure 10 As shown, after 30 minutes of washing, the relative fluorescence intensity of the fluorescent silk yarn decreased to 8856, which is 95.0% of the initial fluorescence intensity. After 400 rubs, its relative fluorescence intensity was 7536, which is 95.7% of the initial relative fluorescence intensity.

[0089] Example 11 This embodiment provides a fluorescent silk yarn and its preparation method.

[0090] Clean silk yarn was placed in a 100 mL beaker, and 40 mL of a 5% (w / w) polyethyleneimine (PEI) solution was added. After stirring for 30 min, 0.1 g of the fluorescent nanospheres prepared in Example 2 was accurately weighed into 40 mL of deionized water. The fluorescent nanospheres were then loaded onto the silk using an electrostatic self-assembly method to prepare fluorescent silk yarn. The prepared fluorescent silk yarn exhibited a bright green fluorescence under 365 nm ultraviolet light irradiation.

[0091] Digital photographs of the nanoscale fluorescent microspheres used in this embodiment under visible light and 365 nm ultraviolet light are shown below. Figure 7 As shown, the microsphere solution appears pale yellow under visible light and emits strong green fluorescence under 365 nm ultraviolet light; the fluorescent silk yarn prepared in this embodiment is as follows. Figure 8 As shown, it exhibits obvious green fluorescence under 365 nm ultraviolet light irradiation; the anti-counterfeiting label prepared from the fluorescent silk yarn in this embodiment is as follows. Figure 9 As shown, it emits bright green fluorescence under 365 nm ultraviolet light; the abrasion resistance and washability of the silk yarn prepared in this embodiment are as follows: Figure 10 As shown, after 30 minutes of washing, its relative fluorescence intensity decreased to 8415, which is 94.8% of the initial relative fluorescence intensity. After 400 rubs, the relative fluorescence intensity of the fluorescent silk yarn decreased to 7499, which is 98.0% of the initial relative fluorescence intensity.

[0092] Example 12 This embodiment provides a fluorescent silk yarn and its preparation method.

[0093] Clean silk yarn was placed in a 100 mL beaker, and 40 mL of a 5% (w / w) polyethyleneimine (PEI) solution was added. After stirring for 30 min, 0.1 g of the fluorescent nanospheres prepared in Example 3 was accurately weighed into 40 mL of deionized water. The fluorescent nanospheres were then loaded onto the silk using an electrostatic self-assembly method to prepare fluorescent silk yarn. The prepared fluorescent silk yarn exhibited a bright blue fluorescence under 365 nm ultraviolet light irradiation.

[0094] Digital photographs of the nanoscale fluorescent microspheres used in this embodiment under visible light and 365 nm ultraviolet light are shown below. Figure 7 As shown, the microsphere solution appears white under visible light and emits strong blue fluorescence under 365 nm ultraviolet light irradiation; the fluorescent silk yarn prepared in this embodiment is as follows. Figure 8As shown, it exhibits obvious blue fluorescence under 365 nm ultraviolet light irradiation; the anti-counterfeiting label prepared from the fluorescent silk yarn in this embodiment is as follows. Figure 9 As shown, it emits strong blue fluorescence under 365 nm ultraviolet light; the abrasion resistance and washability of the silk yarn prepared in this embodiment are as follows: Figure 10 As shown, after 30 minutes of washing, its relative fluorescence intensity decreased to 9057, which is 94.9% of the initial relative fluorescence intensity. After 400 rubs, the relative fluorescence intensity of the fluorescent silk yarn decreased to 8909, which is 94.1% of the initial relative fluorescence intensity.

[0095] In summary, after 0–30 min of water washing and 0–400 rubbing tests, the relative fluorescence intensity of the fluorescent yarn only decreased slightly, remaining at a high level overall. The results indicate that the fluorescent anti-counterfeiting yarns prepared from the three different colored fluorescent microspheres not only possess good photosensitivity but also excellent wearability, meeting the durability and stability requirements of practical applications. These characteristics provide a reliable guarantee for their widespread application in anti-counterfeiting textiles, smart clothing, and functional fabrics.

[0096] For any points not covered above, existing technologies shall apply.

[0097] This application is not limited to the specific methods or compositions described herein, and therefore may vary. It should also be understood that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting, as the scope of this application will be limited only by the appended claims and their equivalents.

Claims

1. A method for preparing water-based nanofluorescent microspheres, characterized in that, The method comprises the following steps: S1, preparing an organic phase: adding a modifier and a stabilizer into a styrene solution and mixing well, and then adding a fluorescent dye to obtain the organic phase; S2, preparing a water-based solution: dispersing a surfactant into deionized water to obtain the water-based solution; S3, slowly pouring the organic phase solution in step S1 into the water-based solution in step S2, and ultrasonic crushing and emulsifying under ice bath conditions; S4, after ultrasonic crushing and emulsification, deoxygenating the reaction system by nitrogen blowing, adding an initiator after heating, continuing to heat after stirring, and reacting under nitrogen protection to prepare nano polymer microspheres by using a microemulsion polymerization method, and obtaining water-based nano fluorescent microspheres through dialysis treatment.

2. The production method according to claim 1, characterized by, The fluorescent dye comprises any one or more of cyanidin, rhodamine B, rhodamine 6G, 7-hydroxycoumarin, fluorescein isothiocyanate, and tetramethyl rhodamine-5-isothiocyanate; The modifier comprises one or more of acrylic acid, sulfonic acid, amide, and ammonia water; The stabilizer comprises any one or more of polyvinylpyrrolidone, hexadecane, and polycarboxylate; The surfactant comprises any one or more of sodium cetyl sulfate, octadecyl trimethyl ammonium bromide, fatty acid monoglyceride, glycerol monostearate, and polyacrylamide sodium methylphenolsulfonate; The initiator comprises any one or more of azobisdimethylamid hydrochloride, potassium persulfate, tert-pentyl hydroperoxide, azobisdimethyl isobutyronitrile, and azobisdimethyl imidazoline hydrochloride.

3. The production method according to claim 2, characterized by, In step S1, the volume mass ratio of the modifier, the stabilizer, the styrene acid, and the fluorescent dye is (1-7) μL:10 mg:200 mg:2 mg.

4. The production method according to claim 3, characterized by, In step S2, the mass concentration of the water-based solution is 1.55-4.8 mg / mL.

5. The production method according to claim 4, characterized by, In step S3, the power of ultrasonic crushing is 200-500 W, and the ultrasonic crushing time is 1-8 min.

6. The production method according to claim 5, characterized by In step S4, the mass ratio of the addition amount of the initiator to the styrene acid is (5-30):10, the temperature for adding the initiator is 50-60 ℃, the reaction temperature is 70-80 ℃, and the reaction time is 7-8 h.

7. An aqueous nanofluorescent microsphere, characterized in that, The method is prepared by any one of claims 1-6.

8. A fluorescent silk yarn, characterized by, The water-based nano fluorescent microspheres are loaded on the surface of the silk yarn by using a cationic monomer to modify the silk yarn and then through an electrostatic self-assembly method.

9. The fluorescent silk yarn according to claim 8, wherein, The cationic monomer is one or more of octadecyl dimethyl benzyl ammonium chloride, hexadecyl trimethyl ammonium chloride, and polyethylene imine.

10. Application of the fluorescent silk yarn in claim any one of claims 8-9 in the preparation of a security mark.

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