Al 3+ Responsive multicolour tunable fluorescent anti-counterfeiting hydrogel and its preparation and application

Abstract

This invention discloses Al 3+ This invention relates to a multi-color tunable fluorescent anti-counterfeiting hydrogel, its preparation method, and its application, belonging to the field of stimulus-responsive fluorescent anti-counterfeiting hydrogel technology. The invention utilizes Al... 3+ Stimulus-responsive small organic molecule B', red layered rare earth hydroxide R, and green layered rare earth hydroxide G are each incorporated into a supramolecular cross-linking network to prepare a single fluorescent anti-counterfeiting hydrogel. Then, based on self-healing, the single fluorescent anti-counterfeiting hydrogel is constructed into a three-color code hydrogel, a 2D multicolor hydrogel, and a 3D multicolor hydrogel. The Al prepared in this invention... 3+ Response-oriented multicolor tunable fluorescent anti-counterfeiting hydrogel with single Al 3+ It exhibits stimulus-responsive color-changing properties, a wide range of adjustable colors, self-healing characteristics, and excellent mechanical properties and color contrast, making it potentially valuable for anti-counterfeiting applications (information encryption and decryption).

Description

Technical Field

[0001] This invention relates to stimulus-responsive fluorescent anti-counterfeiting hydrogels, their preparation methods, and applications, specifically relating to Al. 3+ The responsive multicolor tunable fluorescent anti-counterfeiting hydrogel, its preparation method and application, belong to the field of stimulus-responsive fluorescent anti-counterfeiting hydrogel technology. Background Technology

[0002] With the advancement of technology, we have entered the information age. While enjoying the convenience that information technology brings to our lives, we also face unprecedented threats and challenges to information security.

[0003] Stimulus-responsive anti-counterfeiting hydrogels exhibit changes in shape or color in response to external stimuli (such as temperature, pH, light, electricity, magnetism, and chemicals). These hydrogels possess unique responsiveness to specific stimuli, allowing their hidden information to be decrypted under certain conditions, making them promising candidates for information storage. In recent years, researchers have focused on applying hydrogels to explore modern information storage strategies. For example, Wu Ziliang et al. proposed a robust hydrogel with excellent tunable fluorescence and shape memory capabilities. The encrypted information in this hydrogel can only be read through sequential shape restoration and ultraviolet light irradiation, providing programmable shape design and information encoding for dual encryption (Dual-Encryption in a Shape-Memory Hydrogel with Tunable Fluorescence and Reconfigurable Architecture, Wu Ziliang, Advanced Materials, 2021: 2102023, June 3, 2021).

[0004] These attempts have provided new ideas for developing hydrogel-based information storage materials. However, these strategies also have some drawbacks, such as complex preparation methods and limited, unadjustable fluorescence colors. Therefore, developing anti-counterfeiting platforms with simple preparation methods and adjustable multi-color capabilities is urgently needed, but also quite challenging. Summary of the Invention

[0005] To address the shortcomings of existing technologies, the present invention aims to provide an Al 3+ The invention relates to a responsive, multi-color tunable fluorescent anti-counterfeiting hydrogel, and also provides a simple and easy-to-operate method for preparing the hydrogel.

[0006] To achieve the above objectives, the present invention adopts the following technical solution:

[0007] A three-color code hydrogel, consisting of several square-shaped non-fluorescent hydrogels NP and Al 3+Stimulus-responsive blue fluorescent anti-counterfeiting hydrogel NPB', Al 3+ Stimulus-insensitive green fluorescent anti-counterfeiting hydrogel NPG and Al 3+ The NPR (Non-Resistant Red Fluorescent Hydrogel) anti-counterfeiting hydrogel is built based on self-healing technology using codes from the mobile app ColorCode. Specifically:

[0008] The non-fluorescent hydrogel NP is polymerized from NMA, APS, DPA, PVA and TEMED;

[0009] Al 3+ The stimulus-responsive blue fluorescent anti-counterfeiting hydrogel NPB` is polymerized from NMA, APS, DPA, PVA, small molecule B` and TEMED. The small molecule B` is 2-hydroxyphenyl-1-carbonylhydrazine-1-(benzo[1,3]-oxazin[2,3]-phthalic acid-4-one).

[0010] Al 3+ The stimulus-unresponsive green fluorescent anti-counterfeiting hydrogel NPG is polymerized from NMA, APS, DPA, PVA, LTbH and TEMED.

[0011] Al 3+ The non-responsive red fluorescent anti-counterfeiting hydrogel NPR is polymerized from NMA, APS, DPA, PVA, LEuH, and TEMED.

[0012] The aforementioned method for preparing the three-color code hydrogel includes the following steps:

[0013] (1) Preparation of non-fluorescent hydrogel NP: NMA, APS, DPA and PVA aqueous solution are mixed and completely dissolved. TEMED is added and mixed thoroughly to obtain a precursor solution. The precursor solution is placed in a mold and polymerized at room temperature to obtain a mixture. The mixture is subjected to three freeze / thaw cycles to form non-fluorescent hydrogel NP.

[0014] (2) Preparation of Al 3+ Stimulus-responsive blue fluorescent anti-counterfeiting hydrogel NPB': A mixture of NMA, APS, DPA, PVA aqueous solutions and a small molecule B' solution was thoroughly dissolved. TEMED was then added and mixed thoroughly to obtain a precursor solution. This precursor solution was placed in a mold, and Al was formed using the same method as before. 3+ Stimulus-responsive blue fluorescent anti-counterfeiting hydrogel NPB';

[0015] (3) Preparation of Al 3+ Stimulus-insensitive green fluorescent anti-counterfeiting hydrogel NPG: NMA, APS, DPA, PVA aqueous solutions and LTbH colloidal suspension are mixed and completely dissolved. TEMED is then added and thoroughly mixed to obtain a precursor solution. The precursor solution is placed in a mold, and Al is formed using the same method as before.3+ Stimulus-insensitive green fluorescent anti-counterfeiting hydrogel NPG;

[0016] (4) Preparation of Al 3+ Stimulus-insensitive red fluorescent anti-counterfeiting hydrogel NPR: NMA, APS, DPA, PVA aqueous solutions and LEuH colloidal suspension are mixed and completely dissolved. TEMED is then added and thoroughly mixed to obtain a precursor solution. The precursor solution is placed in a mold, and Al is formed using the same method as before. 3+ NPR (non-responsive red fluorescent anti-counterfeiting hydrogel);

[0017] (5) Cutting: Cut the previously obtained non-fluorescent hydrogels NP and Al 3+ Stimulus-responsive blue fluorescent anti-counterfeiting hydrogel NPB', Al 3+ Stimulus-insensitive green fluorescent anti-counterfeiting hydrogel NPG and Al 3+ The non-responsive red fluorescent anti-counterfeiting hydrogel NPR was cut into squares of the same size.

[0018] (6) Constructing the luminescent array: Place the cut hydrogels on the black substrate and construct the luminescent array based on the self-healing code in the mobile phone software colorcode to obtain the three-color code hydrogel.

[0019] A 2D multicolor hydrogel, consisting of several rectangular Al atoms 3+ Stimulus-responsive red fluorescent anti-counterfeiting hydrogel NPB`R, Al 3+ Stimulus-responsive green fluorescent anti-counterfeiting hydrogel NPB'G and Al 3+ The stimulus-responsive yellow fluorescent anti-counterfeiting hydrogel NPB`GR is based on a self-healing structure, in which:

[0020] Al 3+ The stimulus-responsive red fluorescent anti-counterfeiting hydrogel NPB`R is polymerized from NMA, APS, DPA, PVA, small molecule B`, LEuH and TEMED. The small molecule B` is 2-hydroxyphenyl-1-carbonylhydrazine-1-(benzo[1,3]-oxazin[2,3]-phthalic acid-4-one).

[0021] Al 3+ The stimulus-responsive green fluorescent anti-counterfeiting hydrogel NPB`G is polymerized from NMA, APS, DPA, PVA small molecule B`, LTbH and TEMED;

[0022] Al 3+ The stimulus-responsive yellow fluorescent anti-counterfeiting hydrogel NPB`GR is polymerized from NMA, APS, DPA, PVA, small molecule B`, LTbH, LEuH and TEMED;

[0023] Encrypted information via AI3+ The aqueous solution was written directly onto the self-healing hydrogel.

[0024] The aforementioned method for preparing 2D multicolor hydrogels includes the following steps:

[0025] (1) Preparation of Al 3+ Stimulus-responsive red fluorescent anti-counterfeiting hydrogel NPB'R: NMA, APS, DPA, PVA aqueous solution, small molecule B' solution, and LEuH colloidal suspension are mixed and completely dissolved. TEMED is then added and thoroughly mixed to obtain a precursor solution. The precursor solution is placed in a mold and polymerized at room temperature to obtain a mixture. The mixture undergoes three freeze / thaw cycles to form Al. 3+ Stimulus-responsive red fluorescent anti-counterfeiting hydrogel NPB`R;

[0026] (2) Preparation of Al 3+ Stimulus-responsive green fluorescent anti-counterfeiting hydrogel NPB'G: NMA, APS, DPA, PVA aqueous solution, small molecule B' solution, and LTbH colloidal suspension are mixed and completely dissolved. TEMED is then added and thoroughly mixed to obtain a precursor solution. The precursor solution is placed in a mold, and Al is formed using the same method as before. 3+ Stimulus-responsive green fluorescent anti-counterfeiting hydrogel NPB'G;

[0027] (3) Preparation of Al 3+ Stimulus-responsive yellow fluorescent anti-counterfeiting hydrogel NPB'GR: NMA, APS, DPA, PVA aqueous solution, small molecule B' solution, LTbH colloidal suspension, and LEuH colloidal suspension were mixed and completely dissolved. TEMED was then added and thoroughly mixed to obtain a precursor solution. The precursor solution was placed in a mold, and Al was formed using the same method as before. 3+ Stimulus-responsive yellow fluorescent anti-counterfeiting hydrogel NPB`GR;

[0028] (4) Trimming: Cut the previously obtained Al 3+ Stimulus-responsive red fluorescent anti-counterfeiting hydrogel NPB`R, Al 3+ Stimulus-responsive green fluorescent anti-counterfeiting hydrogel NPB'G and Al 3+ The stimulus-responsive yellow fluorescent anti-counterfeiting hydrogel NPB`GR was cut into several rectangles of the same size.

[0029] (5) Constructing a 2D multicolor hydrogel: Cut the Al 3+ Stimulus-responsive red fluorescent anti-counterfeiting hydrogel NPB`R, Al 3+ Stimulus-responsive green fluorescent anti-counterfeiting hydrogel NPB'G and Al 3+ Stimulus-responsive yellow fluorescent anti-counterfeiting hydrogel NPB`GR was placed on a black substrate, and a 2D multicolor hydrogel was constructed based on self-healing.

[0030] (6) Write encrypted information: using Al 3+ The aqueous solution is used as ink to directly write the encrypted information onto the self-healing hydrogel.

[0031] A 3D multicolor hydrogel, composed of several Al 3+ Stimulus-responsive red fluorescent anti-counterfeiting hydrogel NPB`R, Al 3+ Stimulus-responsive green fluorescent anti-counterfeiting hydrogel NPB'G and Al 3+ The stimulus-responsive yellow fluorescent anti-counterfeiting hydrogel NPB`GR is pieced together into a 3D three-dimensional shape based on self-healing construction, wherein:

[0032] Al 3+ The stimulus-responsive red fluorescent anti-counterfeiting hydrogel NPB`R is polymerized from NMA, APS, DPA, PVA, small molecule B`, LEuH and TEMED. The small molecule B` is 2-hydroxyphenyl-1-carbonylhydrazine-1-(benzo[1,3]-oxazin[2,3]-phthalic acid-4-one).

[0033] Al 3+ The stimulus-responsive green fluorescent anti-counterfeiting hydrogel NPB`G is polymerized from NMA, APS, DPA, PVA small molecule B`, LTbH and TEMED;

[0034] Al 3+ The stimulus-responsive yellow fluorescent anti-counterfeiting hydrogel NPB`GR is polymerized from NMA, APS, DPA, PVA, small molecule B`, LTbH, LEuH and TEMED;

[0035] Encrypted information via AI 3+ The aqueous solution was written directly onto the hydrogel before splicing.

[0036] The aforementioned method for preparing 3D multicolor hydrogels includes the following steps:

[0037] (1) Preparation of Al 3+ Stimulus-responsive red fluorescent anti-counterfeiting hydrogel NPB'R: NMA, APS, DPA, PVA aqueous solution, small molecule B' solution, and LEuH colloidal suspension are mixed and completely dissolved. TEMED is then added and thoroughly mixed to obtain a precursor solution. The precursor solution is placed in a mold and polymerized at room temperature to obtain a mixture. The mixture undergoes three freeze / thaw cycles to form Al. 3+ Stimulus-responsive red fluorescent anti-counterfeiting hydrogel NPB`R;

[0038] (2) Preparation of Al 3+Stimulus-responsive green fluorescent anti-counterfeiting hydrogel NPB'G: NMA, APS, DPA, PVA aqueous solution, small molecule B' solution, and LTbH colloidal suspension are mixed and completely dissolved. TEMED is then added and thoroughly mixed to obtain a precursor solution. The precursor solution is placed in a mold, and Al is formed using the same method as before. 3+ Stimulus-responsive green fluorescent anti-counterfeiting hydrogel NPB'G;

[0039] (3) Preparation of Al 3+ Stimulus-responsive yellow fluorescent anti-counterfeiting hydrogel NPB'GR: NMA, APS, DPA, PVA aqueous solution, small molecule B' solution, LTbH colloidal suspension, and LEuH colloidal suspension were mixed and completely dissolved. TEMED was then added and thoroughly mixed to obtain a precursor solution. The precursor solution was placed in a mold, and Al was formed using the same method as before. 3+ Stimulus-responsive yellow fluorescent anti-counterfeiting hydrogel NPB`GR;

[0040] (4) Trimming: Cut the previously obtained Al 3+ Stimulus-responsive red fluorescent anti-counterfeiting hydrogel NPB`R, Al 3+ Stimulus-responsive green fluorescent anti-counterfeiting hydrogel NPB'G and Al 3+ The stimulus-responsive yellow fluorescent anti-counterfeiting hydrogel NPB`GR was cut into several small pieces;

[0041] (5) Write encrypted information: using Al 3+ The encrypted information was written directly onto the cut hydrogel using an aqueous solution as ink.

[0042] (6) Constructing a 3D multicolor hydrogel: The AI ​​containing the encrypted information... 3+ Stimulus-responsive red fluorescent anti-counterfeiting hydrogel NPB`R, Al 3+ Stimulus-responsive green fluorescent anti-counterfeiting hydrogel NPB'G and Al 3+ Stimulus-responsive yellow fluorescent anti-counterfeiting hydrogels NPB`GR are spliced ​​into a 3D three-dimensional structure, and a 3D multicolor hydrogel is constructed based on self-healing.

[0043] The aforementioned applications of three-color hydrogel, 2D multicolor hydrogel, and 3D multicolor hydrogel in information encryption and decryption.

[0044] The advantages of this invention are:

[0045] (1) Al prepared by the present invention 3+ Response-oriented multicolor tunable fluorescent anti-counterfeiting hydrogel with single Al 3+ It exhibits stimulus-responsive color-changing properties, a wide range of adjustable colors, self-healing characteristics, and good mechanical properties and color contrast, making it potentially valuable for anti-counterfeiting applications (information encryption and decryption).

[0046] (2) The Al provided by the present invention 3+ The preparation method of the responsive multicolor tunable fluorescent anti-counterfeiting hydrogel is simple and easy to operate. Attached Figure Description

[0047] Figure 1 It is a three-color code hydrogel spraying Al 3+ A diagram illustrating the process of reading codes using a mobile app before and after solution preparation;

[0048] Figure 2 It is an Al for 2D multicolor hydrogel 3+ Flowchart of encryption and decryption process for solution-written information;

[0049] Figure 3 It is an Al for 3D multicolor hydrogel 3+ Flowchart of encryption and decryption process for information written in solution. Detailed Implementation

[0050] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments.

[0051] I. Preparation of fluorescent monomers

[0052] 1. Preparation of Al 3+ Stimulus-responsive organic small molecule B'

[0053] The stimulus-responsive organic molecule B' used in this invention is 2-hydroxyphenyl-1-carbazide-1-(benzo[1,3]-oxazin[2,3]-phthalic acid-4-one), and its preparation method specifically includes the following steps:

[0054] (1) In a 250 mL three-necked flask, salicylhydrazide (3.04 g, 0.02 mol) was dissolved in ethanol (30 mL) to obtain salicylhydrazide alcohol solution;

[0055] (2) Dissolve 2.684 g, 0.02 mol of o-phthalaldehyde in 20 mL of ethanol and slowly add it dropwise to a salicylic acid hydrazide solution to obtain a mixture;

[0056] (3) Stir the mixture at 80°C for 12 hours, cool it to room temperature, and evaporate the evaporation under vacuum to obtain a viscous liquid;

[0057] (4) Add 100 mL of deionized water to the viscous liquid to obtain brownish-yellow particles;

[0058] (5) Filter the brownish-yellow particles, wash with water and dry under reduced pressure to obtain the product 2-hydroxybenzene-1-carbonylhydrazine-1-(benzo[1,3]-oxazin[2,3]-phthalic acid-4-one), which is a brown powder (4.186 g, yield 83.7%).

[0059] Due to 2-hydroxyphenyl-1-carbazylhydrazide-1-(benzo[1,3]-oxazin[2,3]-phthalic acid-4-one) in Al 3+ In its presence, it exhibits intramolecular charge transfer (ICT) and chelation fluorescence enhancement (CHET) effects, thus possessing Al... 3+ Stimulus responsiveness (in Al) 3+ (In its presence, it emits blue fluorescence under ultraviolet light).

[0060] 2. Preparation of red layered rare earth hydroxide R

[0061] The red layered rare earth hydroxide R used in this invention is LEuH, and its preparation method specifically includes the following steps:

[0062] (1) Mix Eu(NO3)3·6H2O (2.23g), NaNO3 (4.25g), and deionized water (100mL) to obtain Eu 3+ / Na + Aqueous solution;

[0063] (2) Use a 0.1M NaOH aqueous solution to dissolve Eu 3+ / Na + The pH of the aqueous solution was adjusted to 6.9 to obtain a white suspension. Eu was present in this white suspension. 3+ The concentration is approximately 0.05 mol·L⁻¹ -1 ;

[0064] (3) Place the white suspension in a nitrogen atmosphere and stir overnight at 75°C to obtain white particles;

[0065] (4) The white particles were centrifuged, washed with water and dried under reduced pressure to obtain the product LEuH, which was a white powder (0.94 g, yield 68.35%).

[0066] LEuH exhibits fluorescence (emitting red fluorescence under ultraviolet light), but does not possess Al. 3+ Stimulus responsiveness.

[0067] 3. Preparation of green layered rare earth hydroxide G

[0068] The green layered rare earth hydroxide G used in this invention is LTbH, and its preparation method specifically includes the following steps:

[0069] (1) Mix Tb(NO3)3·6H2O (2.265g), NaNO3 (4.2495g), and deionized water (100mL) to obtain Tb 3 + / Na + Aqueous solution;

[0070] (2) Use a 0.1M NaOH aqueous solution to dissolve Tb 3+ / Na + The pH of the aqueous solution was adjusted to 6.9 to obtain a white suspension. In this white suspension, Tb... 3+ The concentration is approximately 0.05 mol·L⁻¹ -1 ;

[0071] (3) Place the white suspension in a nitrogen atmosphere and stir overnight at 75°C to obtain white particles;

[0072] (4) The white particles were centrifuged, washed with water and dried under reduced pressure to obtain the product LTbH, which was a white powder (1.05 g, yield 74.48%).

[0073] LTbH exhibits fluorescence (emitting green fluorescence under ultraviolet light), but does not possess Al... 3+ Stimulus responsiveness.

[0074] II. Preparation of Single Fluorescent Anti-counterfeiting Hydrogels

[0075] The previously obtained Al 3+ Individual fluorescent anti-counterfeiting hydrogels can be prepared by incorporating any one or more of the following stimuli-responsive small organic molecules B' (2-hydroxyphenyl-1-carbazide-1-(benzo[1,3]-oxazin[2,3]-phthalic acid-4-one)), red layered rare earth hydroxide R (LEuH), and green layered rare earth hydroxide G (LTbH) into a supramolecular cross-linking network.

[0076] 1. Preparation of non-fluorescent hydrogel NP

[0077] Polyvinyl alcohol (PVA) was dissolved in deionized water at 95°C for 2 hours to obtain a PVA aqueous solution with a concentration of 10 wt%.

[0078] Mix 1.1 g N-hydroxymethylacrylamide (NMA), 3 mg ammonium sulfate (APS), 3.2 mg 2,6-pyridinedicarboxylic acid (DPA) and 1 g of 10 wt% PVA aqueous solution (containing 0.1 g PVA). After complete dissolution, add 5 μL of tetramethylethylenediamine (TEMED) and mix thoroughly to obtain the precursor solution.

[0079] The precursor solution was placed in a mold (consisting of two glass plates and a silicon plate sandwiched between the two glass plates, with a thickness of 1 mm) and polymerized at room temperature for 3 hours to obtain a mixture. The mixture was then subjected to three freeze / thaw cycles (freezing at -18°C for 6 hours and then thawing at room temperature for 6 hours) to form a non-fluorescent hydrogel NP.

[0080] 2. Preparation of Al 3+ Stimulus-responsive blue fluorescent anti-counterfeiting hydrogel NPB`

[0081] The previously obtained Al 3+ Stimulus-responsive organic small molecule B' was dispersed in dimethyl sulfoxide (DMSO) and subjected to ultrasonic treatment to obtain a concentration of 40 mg·mL⁻¹. -1 Small molecule B' solution.

[0082] 1.1 g NMA, 3 mg APS, 3.2 mg DPA, 1 g of 10 wt% PVA aqueous solution (preparation method as above, not repeated) and 100 μL of small molecule B' solution (containing 4 mg 2-hydroxyphenyl-1-carbonylhydrazine-1-(benzo[1,3]-oxazin[2,3]-phthalic acid-4-one)) were mixed and completely dissolved. Then 5 μL TEMED was added and mixed thoroughly to obtain the precursor solution.

[0083] The precursor solution was placed in the same mold as before, and the same method was used (polymerization at room temperature for 3 hours to obtain a mixture, which was then subjected to three freeze / thaw cycles (freezing at -18°C for 6 hours, then thawing at room temperature for 6 hours) to form Al). 3+ Stimulus-responsive blue fluorescent anti-counterfeiting hydrogel NPB'.

[0084] 3. Preparation of Al 3+ Stimulus-insensitive green fluorescent anti-counterfeiting hydrogel NPG

[0085] The previously obtained green layered rare earth hydroxide G was dispersed in a 1M aqueous solution of glycine (Gly) and subjected to ultrasonic treatment to obtain a concentration of 10 mg·mL⁻¹. -1 LTbH colloidal suspension.

[0086] Mix 1.1g NMA, 3mg APS, 3.2mg DPA, 1g of 10wt% PVA aqueous solution (preparation method as above, not repeated here) and 200μL LTbH colloidal suspension (containing 2mg LTbH), and after complete dissolution, add 5μL LTEMED and mix thoroughly to obtain the precursor solution.

[0087] The precursor solution was placed in the same mold as before, and the same method was used (polymerization at room temperature for 3 hours to obtain a mixture, which was then subjected to three freeze / thaw cycles (freezing at -18°C for 6 hours, then thawing at room temperature for 6 hours) to form Al). 3+ Stimulus-insensitive green fluorescent anti-counterfeiting hydrogel NPG.

[0088] 4. Preparation of Al 3+ Stimulus-insensitive red fluorescent anti-counterfeiting hydrogel NPR

[0089] The previously obtained red layered rare earth hydroxide R was dispersed in a 1M Gly aqueous solution and subjected to ultrasonic treatment to obtain a concentration of 10 mg·mL⁻¹. -1 LEuH colloidal suspension.

[0090] Mix 1.1g NMA, 3mg APS, 3.2mg DPA, 1g of 10wt% PVA aqueous solution (preparation method as above, not repeated here) and 200μL LEuH colloidal suspension (containing 2mg LEuH), and after complete dissolution, add 5μL LTEMED and mix thoroughly to obtain the precursor solution.

[0091] The precursor solution was placed in the same mold as before, and the same method was used (polymerization at room temperature for 3 hours to obtain a mixture, which was then subjected to three freeze / thaw cycles (freezing at -18°C for 6 hours, then thawing at room temperature for 6 hours) to form Al). 3+ Stimulus-insensitive red fluorescent anti-counterfeiting hydrogel NPR.

[0092] 5. Preparation of Al 3+ Stimulus-responsive red fluorescent anti-counterfeiting hydrogel NPB'R

[0093] 1.1 g NMA, 3 mg APS, 3.2 mg DPA, 1 g of 10 wt% PVA aqueous solution (preparation method as above, not repeated here), and 100 μL of 40 mg·mL⁻¹ PVA solution were prepared. -1 A small molecule B' solution (preparation method as above, not repeated here) and 200 μL of a 10 mg·mL solution. -1 Mix the LEuH colloidal suspension (preparation method is the same as above, and will not be repeated) and after complete dissolution, add 5 μL LTEMED and mix thoroughly to obtain the precursor solution.

[0094] The precursor solution was placed in the same mold as before, and the same method was used (polymerization at room temperature for 3 hours to obtain a mixture, which was then subjected to three freeze / thaw cycles (freezing at -18°C for 6 hours, then thawing at room temperature for 6 hours) to form Al). 3+ Stimulus-responsive red fluorescent anti-counterfeiting hydrogel NPB`R.

[0095] 6. Preparation of Al 3+ Stimulus-responsive green fluorescent anti-counterfeiting hydrogel NPB'G

[0096] 1.1 g NMA, 3 mg APS, 3.2 mg DPA, 1 g of 10 wt% PVA aqueous solution (preparation method as above, not repeated here), and 100 μL of 40 mg·mL⁻¹ PVA solution were prepared. -1 A small molecule B' solution (preparation method as above, not repeated here) and 200 μL of a 10 mg·mL solution. -1 Mix the LTbH colloidal suspension (preparation method as above, not repeated here) and after complete dissolution, add 5 μL LTEMED and mix thoroughly to obtain the precursor solution.

[0097] The precursor solution was placed in the same mold as before, and the same method was used (polymerization at room temperature for 3 hours to obtain a mixture, which was then subjected to three freeze / thaw cycles (freezing at -18°C for 6 hours, then thawing at room temperature for 6 hours) to form Al). 3+ Stimulus-responsive green fluorescent anti-counterfeiting hydrogel NPB`G.

[0098] 7. Preparation of Al 3+ Stimulus-responsive yellow fluorescent anti-counterfeiting hydrogel NPB'GR

[0099] 1.1 g NMA, 3 mg APS, 3.2 mg DPA, 1 g of 10 wt% PVA aqueous solution (preparation method as above, not repeated here), and 100 μL of 40 mg·mL⁻¹ PVA solution were prepared. -1 A small molecule B' solution (preparation method as above, not repeated here), 100 μL of 10 mg·mL -1 LTbH colloidal suspension (preparation method as above, will not be repeated) and 100 μL of 10 mg·mL -1 Mix the LEuH colloidal suspension (preparation method is the same as above, and will not be repeated) and after complete dissolution, add 5 μL LTEMED and mix thoroughly to obtain the precursor solution.

[0100] The precursor solution was placed in the same mold as before, and the same method was used (polymerization at room temperature for 3 hours to obtain a mixture, which was then subjected to three freeze / thaw cycles (freezing at -18°C for 6 hours, then thawing at room temperature for 6 hours) to form Al). 3+ Stimulus-responsive yellow fluorescent anti-counterfeiting hydrogel NPB`GR.

[0101] This invention integrates orthogonal RGB luminescence and ion response characteristics into a single fluorescent anti-counterfeiting hydrogel. The resulting single fluorescent anti-counterfeiting hydrogel can provide a high level of information protection and further improve the security level of advanced anti-counterfeiting.

[0102] III. Preparation of Multicolor Tunable Fluorescent Anti-counterfeiting Hydrogel

[0103] 1. Construction of a self-healing three-color code hydrogel

[0104] The previously obtained non-fluorescent hydrogels NP and Al 3+ Stimulus-responsive blue fluorescent anti-counterfeiting hydrogel NPB', Al 3+ Stimulus-insensitive green fluorescent anti-counterfeiting hydrogel NPG and Al 3+ The non-responsive red fluorescent anti-counterfeiting hydrogel NPR is cut into several squares (e.g., 1cm x 1cm, 1mm thick).

[0105] like Figure 1 As shown, the cut non-fluorescent hydrogels NP and Al are... 3+ Stimulus-responsive blue fluorescent anti-counterfeiting hydrogel NPB', Al 3+ Stimulus-insensitive green fluorescent anti-counterfeiting hydrogel NPG and Al 3+ Stimulus-insensitive red fluorescent anti-counterfeiting hydrogels (NPR) were placed on the same black substrate, and a luminescent array was constructed based on the code in the mobile phone software colorcode, which is self-healing (adjacent hydrogels heal through hydrogen bond interactions at the interface after 24 hours of contact at room temperature), to obtain a three-color code hydrogel.

[0106] The three-color hydrogel appears white in sunlight, making it impossible to distinguish the non-fluorescent hydrogels NP and Al from their colors. 3+ Stimulus-responsive blue fluorescent anti-counterfeiting hydrogel NPB', Al 3+ Stimulus-insensitive green fluorescent anti-counterfeiting hydrogel NPG and Al 3+ Stimulus-insensitive red fluorescent anti-counterfeiting hydrogel NPR.

[0107] The three-color hydrogel, under ultraviolet light irradiation, according to Al... 3+ The solution appears in different colors depending on the spraying method. Specifically:

[0108] (1) Al was not sprayed onto the three-color code hydrogel. 3+ When in solution, the three-color code hydrogel can display three colors: red, green, and black, but scanning the three-color code hydrogel with the mobile phone software colorcode will not reveal any information;

[0109] (2) Spray Al onto the three-color code hydrogel 3+ After being dissolved, the three-color code hydrogel can display four colors: red, green, blue, and black. The correct information can be scanned from the three-color code hydrogel using the mobile phone software colorcode.

[0110] 2. Construction of 2D multicolor hydrogels based on self-healing

[0111] The previously obtained Al 3+ Stimulus-responsive red fluorescent anti-counterfeiting hydrogel NPB`R, Al 3+ Stimulus-responsive green fluorescent anti-counterfeiting hydrogel NPB'G and Al 3+ The stimulus-responsive yellow fluorescent anti-counterfeiting hydrogel NPB`GR was cut into several rectangles of the same size (e.g., 10cm × 1cm, 1mm thick).

[0112] like Figure 2 As shown, cut Al 3+ Stimulus-responsive red fluorescent anti-counterfeiting hydrogel NPB`R, Al 3+ Stimulus-responsive green fluorescent anti-counterfeiting hydrogel NPB'G and Al 3+ Stimulus-responsive yellow fluorescent anti-counterfeiting hydrogels NPB'GR were neatly placed on the same black substrate, and a 2D multicolor hydrogel was constructed based on self-healing (adjacent hydrogels heal through hydrogen bond interactions at the interface after 24 hours of contact at room temperature), and then Al was used. 3+ The aqueous solution is used as ink to directly write encrypted information (e.g., numbers, characters, graphics, images, etc.; in this embodiment, the encrypted information is the uppercase English letters "LZU") onto a 2D multicolor hydrogel.

[0113] The 2D multicolor hydrogel containing the encrypted information appears white in sunlight, making it impossible to distinguish the Al from other materials by color. 3+ Stimulus-responsive red fluorescent anti-counterfeiting hydrogel NPB`R, Al 3+ Stimulus-responsive green fluorescent anti-counterfeiting hydrogel NPB'G and Al 3+ The yellow fluorescent anti-counterfeiting hydrogel NPB`GR responds to stimuli, making the encrypted information even less visible.

[0114] The 2D multicolor hydrogel containing encrypted information displays different colors under ultraviolet light, depending on the specific UV irradiation conditions.

[0115] (1) When irradiated with only 365nm ultraviolet light, the 2D multicolor hydrogel appears blue as a whole, and the encrypted information can be seen. The encrypted information and the color of the splicing area are brighter.

[0116] (2) When irradiated with 365nm and 254nm ultraviolet light at the same time, the 2D multicolor hydrogel exhibits three colors: red, green and yellow. The encrypted information can be seen, and the color of the encrypted information is brighter and clearly different from the surrounding environment color.

[0117] 3. Construction of 3D multicolor hydrogels based on self-healing

[0118] Take a regular hexahedral hydrogel as an example.

[0119] The previously obtained Al 3+ Stimulus-responsive red fluorescent anti-counterfeiting hydrogel NPB`RAl 3+ Stimulus-responsive, green fluorescent anti-counterfeiting hydrogel NPB'G and Al 3+ The stimulus-responsive yellow fluorescent anti-counterfeiting hydrogel NPB`GR was cut into several squares of the same size (e.g., 1cm × 1cm, 1mm thick).

[0120] like Figure 3 As shown, cut Al 3+ Stimulus-responsive red fluorescent anti-counterfeiting hydrogel NPB`R, Al 3+ Stimulus-responsive green fluorescent anti-counterfeiting hydrogel NPB'G and Al 3+ Take two tablets each of the stimulus-responsive yellow fluorescent anti-counterfeiting hydrogel NPB`GR and use Al 3+ An aqueous solution is used as ink to directly write encrypted information (e.g., numbers, characters, graphics, images, etc.; in this embodiment, the encrypted information is the numbers "1, 2, 3, 4, 5, 6") onto each hydrogel. Then, the hydrogels with the encrypted information are spliced ​​together to form a 3D hexahedral shape. Based on self-healing (after 24 hours of contact at room temperature, adjacent hydrogels heal through hydrogen bond interactions at the interface), a 3D multicolor hydrogel is constructed.

[0121] The 3D multicolor hydrogel containing encrypted information, when disassembled sequentially, appears white under sunlight, making it impossible to distinguish the Al from other components by color. 3+ Stimulus-responsive red fluorescent anti-counterfeiting hydrogel NPB`R, Al 3+ Stimulus-responsive green fluorescent anti-counterfeiting hydrogel NPB'G and Al 3+ The yellow fluorescent anti-counterfeiting hydrogel NPB`GR responds to stimuli, making the encrypted information even less visible.

[0122] The 3D multicolor hydrogel containing encrypted information, when disassembled sequentially, displays different colors under ultraviolet light, depending on the specific UV irradiation conditions.

[0123] (1) When irradiated with only 365nm ultraviolet light, each piece of hydrogel turned blue, and the encrypted information could be seen. The encrypted information was brighter.

[0124] (2) When irradiated with 365nm and 254nm ultraviolet light at the same time, each piece of hydrogel appears red, green or yellow, and the encrypted information can be seen. The color of the encrypted information is brighter and is obviously different from the surrounding environment color.

[0125] In summary, the multicolor tunable fluorescent anti-counterfeiting hydrogel prepared by this invention can self-heal and display on color blocks, exhibiting excellent multicolor properties. This characteristic indicates that the multicolor tunable fluorescent anti-counterfeiting hydrogel prepared by this invention has potential application prospects in the field of practical anti-counterfeiting (information encryption and decryption).

[0126] It should be noted that the above embodiments are merely examples for clearly illustrating the present invention, and are not intended to limit the implementation of the present invention. Those skilled in the art can make other variations or modifications based on the above description. It is impossible to exhaustively list all possible implementations here. All obvious variations or modifications derived from the technical solutions of this invention are still within the protection scope of this invention.

Claims

1. A three-color code hydrogel, characterized in that, Composed of several square-shaped non-fluorescent hydrogels NP and Al 3+ Stimulus-responsive blue fluorescent anti-counterfeiting hydrogel NPB', Al 3+ Stimulus-insensitive green fluorescent anti-counterfeiting hydrogel NPG and Al 3+ The NPR (Non-Resistant Red Fluorescent Hydrogel) anti-counterfeiting hydrogel is built based on self-healing technology using codes from the mobile app ColorCode. Specifically: The non-fluorescent hydrogel NP is polymerized from NMA, APS, DPA, PVA and TEMED; Al 3+ The stimulus-responsive blue fluorescent anti-counterfeiting hydrogel NPB` is polymerized from NMA, APS, DPA, PVA, small molecule B` and TEMED. The small molecule B` is 2-hydroxyphenyl-1-carbonylhydrazine-1-(benzo[1,3]-oxazin[2,3]-phthalic acid-4-one). Al 3+ The stimulus-unresponsive green fluorescent anti-counterfeiting hydrogel NPG is polymerized from NMA, APS, DPA, PVA, LTbH and TEMED. Al 3+ The non-responsive red fluorescent anti-counterfeiting hydrogel NPR is polymerized from NMA, APS, DPA, PVA, LEuH, and TEMED.

2. The method for preparing the three-color code hydrogel according to claim 1, characterized in that, Includes the following steps: (1) Preparation of non-fluorescent hydrogel NP: NMA, APS, DPA and PVA aqueous solution are mixed and completely dissolved. TEMED is added and mixed thoroughly to obtain a precursor solution. The precursor solution is placed in a mold and polymerized at room temperature to obtain a mixture. The mixture is subjected to three freeze / thaw cycles to form non-fluorescent hydrogel NP. (2) Preparation of Al 3+ Stimulus-responsive blue fluorescent anti-counterfeiting hydrogel NPB': A mixture of NMA, APS, DPA, PVA aqueous solutions and a small molecule B' solution was thoroughly dissolved. TEMED was then added and mixed thoroughly to obtain a precursor solution. This precursor solution was placed in a mold, and Al was formed using the same method as before. 3+ Stimulus-responsive blue fluorescent anti-counterfeiting hydrogel NPB'; (3) Preparation of Al 3+ Stimulus-insensitive green fluorescent anti-counterfeiting hydrogel NPG: NMA, APS, DPA, PVA aqueous solutions and LTbH colloidal suspension are mixed and completely dissolved. TEMED is then added and thoroughly mixed to obtain a precursor solution. The precursor solution is placed in a mold, and Al is formed using the same method as before. 3+ Stimulus-insensitive green fluorescent anti-counterfeiting hydrogel NPG; (4) Preparation of Al 3+ Stimulus-insensitive red fluorescent anti-counterfeiting hydrogel NPR: NMA, APS, DPA, PVA aqueous solutions and LEuH colloidal suspension are mixed and completely dissolved. TEMED is then added and thoroughly mixed to obtain a precursor solution. The precursor solution is placed in a mold, and Al is formed using the same method as before. 3+ NPR (non-responsive red fluorescent anti-counterfeiting hydrogel); (5) Cutting: Cut the previously obtained non-fluorescent hydrogels NP and Al 3+ Stimulus-responsive blue fluorescent anti-counterfeiting hydrogel NPB', Al 3+ Stimulus-insensitive green fluorescent anti-counterfeiting hydrogel NPG and Al 3+ The non-responsive red fluorescent anti-counterfeiting hydrogel NPR was cut into squares of the same size. (6) Constructing the luminescent array: Place the cut hydrogels on the black substrate and construct the luminescent array based on the self-healing code in the mobile phone software colorcode to obtain the three-color code hydrogel.

3. The application of the three-color hydrogel as described in claim 1 in information encryption and decryption.

4. A 2D multicolor hydrogel, characterized in that, Composed of several rectangular Al 3+ Stimulus-responsive red fluorescent anti-counterfeiting hydrogel NPB`R, Al 3+ Stimulus-responsive green fluorescent anti-counterfeiting hydrogel NPB'G and Al 3+ The stimulus-responsive yellow fluorescent anti-counterfeiting hydrogel NPB`GR is based on a self-healing structure, in which: Al 3+ The stimulus-responsive red fluorescent anti-counterfeiting hydrogel NPB`R is polymerized from NMA, APS, DPA, PVA, small molecule B`, LEuH and TEMED. The small molecule B` is 2-hydroxyphenyl-1-carbonylhydrazine-1-(benzo[1,3]-oxazin[2,3]-phthalic acid-4-one). Al 3+ The stimulus-responsive green fluorescent anti-counterfeiting hydrogel NPB`G is polymerized from NMA, APS, DPA, PVA small molecule B`, LTbH and TEMED; Al 3+ The stimulus-responsive yellow fluorescent anti-counterfeiting hydrogel NPB`GR is polymerized from NMA, APS, DPA, PVA, small molecule B`, LTbH, LEuH and TEMED; Encrypted information via AI 3+ The aqueous solution was written directly onto the self-healing hydrogel.

5. The method for preparing the 2D multicolor hydrogel according to claim 4, characterized in that, Includes the following steps: (1) Preparation of Al 3+ Stimulus-responsive red fluorescent anti-counterfeiting hydrogel NPB'R: NMA, APS, DPA, PVA aqueous solution, small molecule B' solution, and LEuH colloidal suspension are mixed and completely dissolved. TEMED is then added and thoroughly mixed to obtain a precursor solution. The precursor solution is placed in a mold and polymerized at room temperature to obtain a mixture. The mixture undergoes three freeze / thaw cycles to form Al. 3+ Stimulus-responsive red fluorescent anti-counterfeiting hydrogel NPB`R; (2) Preparation of Al 3+ Stimulus-responsive green fluorescent anti-counterfeiting hydrogel NPB'G: NMA, APS, DPA, PVA aqueous solution, small molecule B' solution, and LTbH colloidal suspension are mixed and completely dissolved. TEMED is then added and thoroughly mixed to obtain a precursor solution. The precursor solution is placed in a mold, and Al is formed using the same method as before. 3+ Stimulus-responsive green fluorescent anti-counterfeiting hydrogel NPB'G; (3) Preparation of Al 3+ Stimulus-responsive yellow fluorescent anti-counterfeiting hydrogel NPB'GR: NMA, APS, DPA, PVA aqueous solution, small molecule B' solution, LTbH colloidal suspension, and LEuH colloidal suspension were mixed and completely dissolved. TEMED was then added and thoroughly mixed to obtain a precursor solution. The precursor solution was placed in a mold, and Al was formed using the same method as before. 3+ Stimulus-responsive yellow fluorescent anti-counterfeiting hydrogel NPB`GR; (4) Trimming: Cut the previously obtained Al 3+ Stimulus-responsive red fluorescent anti-counterfeiting hydrogel NPB`R, Al 3+ Stimulus-responsive green fluorescent anti-counterfeiting hydrogel NPB'G and Al 3+ The stimulus-responsive yellow fluorescent anti-counterfeiting hydrogel NPB`GR was cut into several rectangles of the same size. (5) Constructing a 2D multicolor hydrogel: Cut the Al 3+ Stimulus-responsive red fluorescent anti-counterfeiting hydrogel NPB`R, Al 3+ Stimulus-responsive green fluorescent anti-counterfeiting hydrogel NPB'G and Al 3+ Stimulus-responsive yellow fluorescent anti-counterfeiting hydrogel NPB`GR was placed on a black substrate, and a 2D multicolor hydrogel was constructed based on self-healing. (6) Write encrypted information: using Al 3+ The aqueous solution is used as ink to directly write the encrypted information onto the self-healing hydrogel.

6. The application of the 2D multicolor hydrogel according to claim 4 in information encryption and decryption.

7. A 3D multicolor hydrogel, characterized in that, Composed of several Al 3+ Stimulus-responsive red fluorescent anti-counterfeiting hydrogel NPB`R, Al 3+ Stimulus-responsive green fluorescent anti-counterfeiting hydrogel NPB'G and Al 3+ The stimulus-responsive yellow fluorescent anti-counterfeiting hydrogel NPB`GR is pieced together into a 3D three-dimensional shape based on self-healing construction, wherein: Al 3+ The stimulus-responsive red fluorescent anti-counterfeiting hydrogel NPB`R is polymerized from NMA, APS, DPA, PVA, small molecule B`, LEuH and TEMED. The small molecule B` is 2-hydroxyphenyl-1-carbonylhydrazine-1-(benzo[1,3]-oxazin[2,3]-phthalic acid-4-one). Al 3+ The stimulus-responsive green fluorescent anti-counterfeiting hydrogel NPB`G is polymerized from NMA, APS, DPA, PVA small molecule B`, LTbH and TEMED; Al 3+ The stimulus-responsive yellow fluorescent anti-counterfeiting hydrogel NPB`GR is polymerized from NMA, APS, DPA, PVA, small molecule B`, LTbH, LEuH and TEMED; Encrypted information via AI 3+ The aqueous solution was written directly onto the hydrogel before splicing.

8. The method for preparing the 3D multicolor hydrogel according to claim 7, characterized in that, Includes the following steps: (1) Preparation of Al 3+ Stimulus-responsive red fluorescent anti-counterfeiting hydrogel NPB'R: NMA, APS, DPA, PVA aqueous solution, small molecule B' solution, and LEuH colloidal suspension are mixed and completely dissolved. TEMED is then added and thoroughly mixed to obtain a precursor solution. The precursor solution is placed in a mold and polymerized at room temperature to obtain a mixture. The mixture undergoes three freeze / thaw cycles to form Al. 3+ Stimulus-responsive red fluorescent anti-counterfeiting hydrogel NPB`R; (2) Preparation of Al 3+ Stimulus-responsive green fluorescent anti-counterfeiting hydrogel NPB'G: NMA, APS, DPA, PVA aqueous solution, small molecule B' solution, and LTbH colloidal suspension are mixed and completely dissolved. TEMED is then added and thoroughly mixed to obtain a precursor solution. The precursor solution is placed in a mold, and Al is formed using the same method as before. 3+ Stimulus-responsive green fluorescent anti-counterfeiting hydrogel NPB'G; (3) Preparation of Al 3+ Stimulus-responsive yellow fluorescent anti-counterfeiting hydrogel NPB'GR: NMA, APS, DPA, PVA aqueous solution, small molecule B' solution, LTbH colloidal suspension, and LEuH colloidal suspension were mixed and completely dissolved. TEMED was then added and thoroughly mixed to obtain a precursor solution. The precursor solution was placed in a mold, and Al was formed using the same method as before. 3+ Stimulus-responsive yellow fluorescent anti-counterfeiting hydrogel NPB`GR; (4) Trimming: Cut the previously obtained Al 3+ Stimulus-responsive red fluorescent anti-counterfeiting hydrogel NPB`R, Al 3+ Stimulus-responsive green fluorescent anti-counterfeiting hydrogel NPB'G and Al 3+ The stimulus-responsive yellow fluorescent anti-counterfeiting hydrogel NPB`GR was cut into several small pieces; (5) Write encrypted information: using Al 3+ The encrypted information was written directly onto the cut hydrogel using an aqueous solution as ink. (6) Constructing a 3D multicolor hydrogel: The AI ​​containing the encrypted information... 3+ Stimulus-responsive red fluorescent anti-counterfeiting hydrogel NPB`R, Al 3+ Stimulus-responsive green fluorescent anti-counterfeiting hydrogel NPB'G and Al 3+ Stimulus-responsive yellow fluorescent anti-counterfeiting hydrogels NPB`GR are spliced ​​into a 3D three-dimensional structure, and a 3D multicolor hydrogel is constructed based on self-healing.

9. The application of the 3D multicolor hydrogel according to claim 7 in information encryption and decryption.

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