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CN-118063985-B - Preparation method and application of light-responsive fluorescent photonic crystal anti-counterfeiting coating

CN118063985BCN 118063985 BCN118063985 BCN 118063985BCN-118063985-B

Abstract

The invention relates to the field of paint, and discloses a preparation method and application of a light-responsive fluorescent photonic crystal anti-counterfeiting paint. The preparation method comprises the steps of S1 preparing carbon black @ silicon dioxide nanospheres, S2 dissolving citric acid and urea in water for reaction, obtaining carbon quantum dot mother liquor after dialysis and purification, and S3 dispersing the carbon black @ silicon dioxide nanospheres and the carbon quantum dot mother liquor in an alcohol solvent, adding PVP, and uniformly stirring to obtain the light-responsive fluorescent photonic crystal anti-counterfeiting material. The coating contains the carbon quantum dots and the photonic crystals, and the structural color of the photonic crystals and the ultraviolet excitation fluorescence characteristic of the carbon quantum dots are utilized, so that the coating can be endowed with excellent light response fluorescence anti-counterfeiting function, and various anti-counterfeiting patterns can be constructed by utilizing the coating.

Inventors

  • GONG XINMING
  • Hou Maohua
  • XU BIN

Assignees

  • 浙江画之都文化创意有限公司

Dates

Publication Date
20260505
Application Date
20240207

Claims (10)

  1. 1. A preparation method of a light response type fluorescent photon crystal anti-counterfeiting coating is characterized by comprising the following steps: s1, preparing carbon black@silicon dioxide nanospheres with the particle size of 350-400 nm; S2, dissolving citric acid and urea in water for reaction, and dialyzing and purifying to obtain carbon quantum dot mother liquor, wherein the particle size of the carbon quantum dots is less than or equal to 10nm; S3, dispersing the carbon black@silicon dioxide nanospheres obtained in the step S1 and the carbon quantum dot mother solution obtained in the step S2 in an alcohol solvent, adding PVP, and uniformly stirring to obtain the light response type fluorescent photonic crystal anti-counterfeiting coating; In the light response type fluorescent photonic crystal anti-counterfeiting coating, the concentration of carbon black@silicon dioxide nanospheres is 3-10wt%, the concentration of carbon quantum dots is 1-2.5wt%, and the concentration of PVP is 0.2-0.4wt%.
  2. 2. The method of claim 1, wherein the carbon quantum dots have a particle size of 5nm or less in S2.
  3. 3. The method of claim 2, wherein the ratio of citric acid, urea and water in S2 is 0.3-0.5 g/0.2-0.4 g/8-12 ml.
  4. 4. The method of claim 2, wherein the reaction temperature is 150-200 ℃ and the reaction time is 8-12 hours in S2.
  5. 5. The preparation method of the water-based dialysis membrane according to claim 2, wherein in S2, the molecular weight cut-off of a dialysis bag used for dialysis is 500-1000 Da, the solution used for dialysis is deionized water, and the dialysis time is 12-24 hours.
  6. 6. The preparation method of the fluorescent photonic crystal anti-counterfeiting coating according to claim 1, wherein in S3, the concentration of carbon black@silica nanospheres is 3-6wt%.
  7. 7. The preparation method of the carbon black/silica nanospheres and the carbon quantum dot mother solution are dispersed in an alcohol solvent in an ultrasonic mode for 1-2 h in S3.
  8. 8. The method of claim 1, wherein in S3, the stirring speed is 200-500 rpm, and the stirring time is 30-90 min.
  9. 9. The method according to claim 1, wherein in S3, the alcohol solvent is ethanol.
  10. 10. The application of the light-responsive fluorescent photonic crystal anti-counterfeiting coating obtained by the preparation method according to any one of claims 1-9 in preparation of fluorescent anti-counterfeiting patterns.

Description

Preparation method and application of light-responsive fluorescent photonic crystal anti-counterfeiting coating Technical Field The invention relates to the field of paint, in particular to a preparation method and application of a light-responsive fluorescent photonic crystal anti-counterfeiting paint. Background In the long-term development of human society, chemical pigments have been widely used in various industries such as textiles, pharmaceuticals, cosmetics, etc. However, not only does chemical dyes cause serious environmental pollution, but the dyed color fades with time. In recent years, photonic crystals have been widely used in high-end products such as decorations, cosmetics, textiles, and the like because they possess a structural color that is free from contamination and does not fade. However, in the field of high-end products, counterfeit problems are becoming more serious, greatly compromising country, enterprise reputation and consumer rights. Therefore, the development of the novel anti-counterfeiting technology has important significance for improving the state image, improving the enterprise reputation and maintaining the rights and interests of consumers. However, the traditional anti-counterfeiting technologies such as bar codes, watermarks, laser holograms and the like are easy and single in decryption mode and easy to crack and imitate due to the fact that images and colors of the traditional anti-counterfeiting technologies are fixed and visible. Therefore, there is a need to develop new anti-counterfeiting technologies with variable colors. The quantum dot fluorescent anti-counterfeiting technology has important application value in the technical field of optical anti-counterfeiting because of the optical characteristics of instantaneous color generation, high fluorescent brightness, adjustable fluorescent color and the like. The carbon quantum dot is used as a novel fluorescent nano material, has the characteristics of high fluorescence yield, good chemical stability, low cost, low toxicity and the like, and becomes a hot spot in the field of luminescent material research. If the carbon quantum dots are combined with the photonic crystal to prepare the fluorescent structure color anti-counterfeiting pattern, the fluorescent structure color anti-counterfeiting pattern can be applied to products such as home ornaments, clothing textiles and the like, and the functionality and anti-counterfeiting complexity of the products can be greatly improved. However, in the early experiments of the applicant, on one hand, after doping and adding the carbon quantum dots into a system containing the photonic crystal, the carbon quantum dots are difficult to fully disperse, so that the fluorescence quenching phenomenon is easily caused by the fact that the local concentration of the carbon quantum dots is too high, and the fluorescence intensity is greatly reduced, and on the other hand, the doping of the carbon quantum dots also influences the structural color development of the photonic crystal. Disclosure of Invention In order to solve the technical problems, the invention provides a preparation method and application of a light-responsive fluorescent photonic crystal anti-counterfeiting coating. The coating contains the carbon quantum dots and the photonic crystals, and the structural color of the photonic crystals and the ultraviolet excitation fluorescence characteristic of the carbon quantum dots are utilized, so that the coating can be endowed with excellent light response fluorescence anti-counterfeiting function, and various anti-counterfeiting patterns can be constructed by utilizing the coating. The specific technical scheme of the invention is as follows: in a first aspect, the invention provides a preparation method of a light-responsive fluorescent photonic crystal anti-counterfeiting coating, which comprises the following steps: s1, preparing carbon black@silicon dioxide nanospheres; S2, dissolving citric acid and urea in water for reaction, and dialyzing and purifying to obtain carbon quantum dot mother liquor, wherein the particle size of the carbon quantum dots is less than or equal to 10nm; s3, dispersing the carbon black@silicon dioxide nanospheres obtained in the step S1 and the carbon quantum dot mother solution obtained in the step S2 in an alcohol solvent, adding PVP (polyvinylpyrrolidone), and uniformly stirring to obtain a light response type fluorescent photonic crystal anti-counterfeiting material; In the light response type fluorescent photon crystal anti-counterfeiting material, the concentration range of carbon black@silicon dioxide nanospheres is 3-10wt%, the concentration of carbon quantum dots is 0.5-5wt%, and the concentration of PVP is 0.1-0.7wt%. In the step S1, the carbon black@silicon dioxide nanospheres are prepared, and the obtained carbon black@silicon dioxide nanospheres can self-assemble an orderly arranged photonic crystal structure after coating, an