A photonic crystal time-temperature indicating film device and a preparation method thereof

Abstract

The present application relates to a kind of photonic crystal time-temperature indicating film device and its preparation method, belong to new material field.A kind of photonic crystal time-temperature indicating film device, the time-temperature indicating film device includes substrate and the indicating film attached to it, the indicating film is prepared by the central region of one-dimensional photonic crystal film after being treated by alkaline aqueous solution;The one-dimensional photonic crystal film is formed by inorganic nanoparticle disorder accumulation layer and copolymer nanoparticle disorder accumulation layer on substrate alternately stacked.The photonic crystal time-temperature indicating film device of the present application has the advantages of bright color, reusable, simple preparation method, can be customized according to the demand time-temperature indicating range, and is expected to be used as a new type of time-temperature indicating device.

Description

Technical Field

[0001] This invention relates to a photonic crystal time-temperature indicator thin film device and its fabrication method, belonging to the field of new materials. Background Technology

[0002] Cold storage and transportation are crucial for the preservation of many biomedical and chemical products (such as vaccines and blood). Ensuring these substances remain under appropriate temperature conditions throughout storage and transportation is essential for their quality and efficacy. Traditional temperature indicators primarily focus on monitoring the current temperature, but cannot acquire historical temperature information during cold storage and transportation, limiting comprehensive monitoring of product quality and efficacy. Time-temperature indicators use physical or chemical changes to generate a cumulative effect of time and temperature, recording the product's temperature history and indicating remaining quality and efficacy. Electronic time-temperature indicators are highly sensitive and accurate, but they are expensive, and discarded electronic waste can burden the environment. Material-based indicators mainly fall into two categories: chemical reaction-based and diffusion-based. Chemical reaction-based indicators rely on enzymes or chemical reagents undergoing chemical reactions at specific temperatures to produce color changes, recording time-temperature history and indicating product quality. These indicators typically have high activation temperatures, making them unsuitable for low-temperature environments, and may pose a risk of small molecule leakage, indicating safety hazards. Diffusion-type indicators typically consist of temperature-sensitive dyes and porous materials. When the temperature reaches the dye's melting point, the dye undergoes a phase transition and diffuses within the porous material, recording the temperature change process through this diffusion. However, such indicators require modular sealing to prevent dye leakage during diffusion. Furthermore, the dye is prone to discoloration (i.e., photobleaching) under prolonged light exposure. Therefore, a novel time-temperature indicator is needed to provide a more reliable quality assurance method for the refrigeration, storage, and transportation of biopharmaceutical products. Summary of the Invention

[0003] This invention provides a photonic crystal time-temperature indicator thin-film device and its fabrication method. This device records the history of cold chain storage and transportation temperatures and indicates product efficacy based on the appearance, disappearance, and structural color changes of a water vapor-induced photonic crystal pattern, without requiring chemical reactions or physical diffusion processes, thus eliminating the risk of small molecule leakage.

[0004] A photonic crystal time-temperature indicating thin-film device, the time-temperature indicating thin-film device comprising a substrate and an indicating thin film attached thereon,

[0005] The indicator film is prepared by treating the central region of a one-dimensional photonic crystal film with an alkaline aqueous solution;

[0006] The one-dimensional photonic crystal film is formed by alternating stacking of inorganic nanoparticle disordered stacking layers and copolymer nanoparticle disordered stacking layers on a substrate.

[0007] In the above technical solution, the "central region" of the one-dimensional photonic crystal thin film is a single continuous region defined outward from the center of the one-dimensional photonic crystal thin film. For example, a circular region defined with the center of the one-dimensional photonic crystal thin film as the center.

[0008] Furthermore, the inorganic nanoparticles are one of titanium dioxide, zirconium dioxide, zinc oxide, and aluminum oxide.

[0009] Furthermore, the inorganic nanoparticles have a particle size of 10–80 nm.

[0010] Furthermore, the copolymer nanoparticles are prepared by microemulsion polymerization of hydrophobic monomers and carboxyl-containing monomers, with a feeding ratio of hydrophobic monomers to carboxyl-containing monomers of 30:1 to 3:1, more preferably 15:1 to 8:1.

[0011] The hydrophobic monomer is one of methyl methacrylate, styrene, methyl acrylate, ethyl methacrylate, and butyl methacrylate;

[0012] The carboxyl-containing polymeric monomer is one of acrylic acid, methacrylic acid, 2-ethylacrylic acid, 2-propylacrylic acid, and 3-butenoic acid.

[0013] Furthermore, the copolymer nanoparticles have a particle size of 30–80 nm.

[0014] Preferably, the alkaline aqueous solution is one of sodium carbonate, sodium bicarbonate, sodium hydroxide, potassium carbonate, and potassium bicarbonate aqueous solution, and the concentration of the aqueous solution is 0.001-5M, preferably 0.01-0.1M.

[0015] Preferably, the treatment time of the central region of the one-dimensional photonic crystal thin film in an alkaline aqueous solution is 1 to 300 s, more preferably 20 to 120 s.

[0016] Preferably, the alkaline treatment of the central region of the one-dimensional photonic crystal thin film is achieved with the assistance of a perforated mask.

[0017] Furthermore, the shape of the cutout in the perforated mask is not particularly limited, but is preferably a regular shape for preparation and observation, such as a circle, a square, etc.

[0018] Preferably, the substrate for assembling the one-dimensional photonic crystal includes one of silicon wafer, glass, polyethylene terephthalate board (film), polystyrene board (film), and polydimethylsiloxane film.

[0019] The color of the device is a structural color produced by the modulation of visible light by the periodic micro and nano structures of the photonic crystal, and it has anti-photobleaching properties. The photonic crystal time-temperature indicating thin film device can be used to record time-temperature history changes within a temperature range of -30℃ to 35℃, providing a wide temperature monitoring range.

[0020] The photonic crystal time-temperature indicating thin-film device provided by this invention initially exhibits a uniform blue color. Under saturated water vapor (human breath) stimulation, an orange indicator pattern appears in the central region of the device surface. When the water vapor evaporates, the central orange pattern disappears, and the device returns to its initial blue, patternless state. The color of the indicator pattern appearing on the device surface under saturated water vapor stimulation can be effectively controlled by adjusting the preparation parameters. At room temperature, over time, water molecules in the environment gradually diffuse into the device interior, inducing the copolymer to form a hydrogen bond network, locking the internal structure of the device. This causes the color of the pattern displayed by the indicating device under saturated water vapor stimulation to gradually shift towards shorter wavelengths as the storage time in a room temperature environment increases. More specifically, for example, in a 25°C room temperature environment, the original indicator displays an orange indicator pattern under saturated water vapor stimulation. After 24 hours of storage, no indicator pattern appears under water vapor stimulation, meaning that the central pattern display area of ​​the indicator loses its color-changing response to saturated water vapor stimulation. At a 0°C refrigeration temperature, after 24 hours of storage, the indicator displays a green indicator pattern under water vapor stimulation, meaning that the central pattern display area of ​​the indicator has reduced its color-changing response to saturated water vapor stimulation. After 24 hours of storage at a -30°C freezing temperature, the indicator displays an orange indicator pattern under saturated water vapor stimulation, maintaining the initial color-changing response of the device to saturated water vapor stimulation.

[0021] The photonic crystal indicator film exhibits an irreversible color change in response to saturated water vapor stimulation, which changes with ambient temperature and time. The higher the temperature, the faster the color change disappears under saturated water vapor stimulation. This characteristic aligns with the properties of many biological agents and chemical drugs requiring refrigerated storage and transportation. Therefore, it can be used to monitor the refrigerated storage and transportation process of such items, recording the time-temperature history of the appearance, disappearance, and color changes of the indicator pattern using the film device, thus indicating the quality and efficacy of the item after refrigerated storage and transportation.

[0022] Another object of the present invention is to provide a method for fabricating the above-mentioned photonic crystal time-temperature indicating thin film device.

[0023] A method for fabricating a photonic crystal time-temperature indicating thin-film device includes the following process steps:

[0024] ① Copolymer nanoparticles were prepared using microemulsion polymerization;

[0025] ② The prepared copolymer nanoparticles and inorganic nanoparticles are alternately stacked on the substrate surface by a layer-by-layer self-assembly method to prepare a one-dimensional photonic crystal film.

[0026] ③ Place the one-dimensional photonic crystal in a sealed container containing saturated ethanol vapor for 1 minute to allow the copolymer nanoparticles to swell and deswell and connect to form a film, thereby enhancing the structural stability of the film.

[0027] ④ Heat the one-dimensional photonic crystal thin film after step ③ at 50-150℃ for 1-20 min, preferably at 80-100℃ for 3-10 min;

[0028] ⑤ The perforated mask is tightly attached to the surface of the one-dimensional photonic crystal. Alkali solution is dropped onto the surface of the photonic crystal. The exposed area is soaked in the alkali solution, while the mask-protected area does not come into contact with the alkali solution.

[0029] ⑥ Rinse off the alkaline solution on the surface of the one-dimensional photonic crystal thin film with deionized water, blow off the surface moisture, and remove the mask to obtain the photonic crystal time-temperature indicator thin film device.

[0030] In the above technical solutions, the preparation methods of copolymer nanoparticles, inorganic nanoparticles, and layer-by-layer self-assembly methods are all existing technologies, and those skilled in the art can prepare them according to the disclosed content of the existing technologies (J. Mater. Chem. 2009, 19, 3500; Chem. Eng. J. 2019, 375, 121987).

[0031] The thickness of the one-dimensional photonic crystal film described in this invention is determined by the number of self-assemblies layer by layer. The number of assembly times for the two assembly materials is preferably 3 to 6 times each, and the thickness of the one-dimensional photonic crystal film is preferably 400 to 600 nm.

[0032] In the above process steps, increasing the concentration of the alkali solution or extending the treatment time of the alkali solution on the photonic crystal can shift the color of the indicator pattern produced by the indicator under saturated water vapor stimulation towards longer wavelengths, which can be used for quality monitoring during longer product storage and transportation processes. For example, an indicator that displays a red indicator pattern under saturated water vapor stimulation can be used to record the temperature history changes of the product during storage and transportation over a 48-hour period, indicating the quality and effectiveness of the product after storage and transportation.

[0033] The beneficial effects of this invention are as follows: This invention provides a method for preparing a photonic crystal time-temperature indicating thin-film device. This method involves preparing the device by alkali treatment of a one-dimensional photonic crystal thin film containing carboxyl groups. By adjusting the concentration of the alkali solution and the treatment time of the one-dimensional photonic crystal, thin-film devices for indicating different time-temperature ranges can be prepared. The photonic crystal time-temperature indicating thin-film device of this invention has the advantages of bright color, reusability, simple preparation method, and customizable time-temperature indication range according to requirements, and is expected to be used as a novel time-temperature indicating device. Attached Figure Description

[0034] Figure 1 The photonic crystal time-temperature indicator prepared in Example 1 is shown in color photographs of the response to saturated water vapor after being stored for different times at 0°C and 25°C.

[0035] Figure 2 The reflection wavelengths of the photonic crystal time-temperature indicator prepared in Example 1 after storage for different times at different temperatures are shown.

[0036] Figure 3 Color photographs of the response to saturated water vapor after storing the photonic crystal time-temperature indicators prepared in Examples 2 and 3 at 0°C and 25°C for different times. Detailed Implementation

[0037] The following non-limiting embodiments are intended to enable those skilled in the art to more fully understand the invention, but do not limit the invention in any way.

[0038] Unless otherwise specified, the experimental methods described in the following examples are conventional methods; the reagents and materials described are commercially available unless otherwise specified.

[0039] Example 1

[0040] Weigh 1.0 g of acrylic acid and 10.0 g of methyl methacrylate and mix them thoroughly. Dissolve 1.0 g of hexadecyltrimethylammonium bromide in 40 mL of deionized water and add it to a 150 mL three-necked flask. Add 2.0 g of the above monomer mixture to the reaction flask. Under nitrogen protection and stirring at 400 rpm, heat to 75 °C. After 20 min, add 4 mL of an aqueous solution containing 75 mg of potassium persulfate. After reacting for 20 min, add the remaining monomer mixture dropwise to the reaction flask through a constant pressure dropping funnel. After the addition is complete, maintain the temperature and react for another 30 min. Cool to room temperature to obtain an aqueous dispersion of copolymer nanoparticles with a particle size of approximately 40 nm.

[0041] The above copolymer nanoparticle dispersion was diluted with water to 3.0 wt%. This dispersion, along with a 2.0 wt% aqueous dispersion of titanium dioxide nanoparticles with a particle size of approximately 25 nm, was alternately coated three times on a silicon wafer surface using spin-coating technology to prepare a one-dimensional photonic crystal with a thickness of approximately 500 nm. The one-dimensional photonic crystal was sealed in a closed container containing saturated ethanol vapor for 2 minutes. After being removed from the container, it was heated on a 100°C hot plate for 5 minutes. After the photonic crystal cooled, a perforated mask was tightly adhered to its surface. A 0.1 M Na₂CO₃ aqueous solution was dropped onto the sample surface. After 60 seconds, the surface was rinsed with deionized water, and the moisture on the photonic crystal surface was dried. After removing the mask, the photonic crystal time-temperature indicator device was obtained.

[0042] Examples 2-5

[0043] The method is the same as in Example 1, but the alkaline treatment conditions are as follows: 0.1M Na2CO3 aqueous solution treatment for 30s, 0.1M Na2CO3 aqueous solution treatment for 90s, 0.01M Na2CO3 aqueous solution treatment for 60s, and 0.1M NaHCO3 aqueous solution treatment for 30s.

[0044] Example 6

[0045] Weigh 1.0 g of methacrylic acid and 10.0 g of ethyl methacrylate and mix them thoroughly. Dissolve 1.0 g of hexadecyltrimethylammonium bromide in 40 mL of deionized water and add it to a 150 mL three-necked flask. Add 2.0 g of the above monomer mixture to the reaction flask. Under nitrogen protection and stirring at 400 rpm, heat to 75 °C and stir for 20 min. Then add 4 mL of an aqueous solution containing 75 mg of potassium persulfate. After reacting for 20 min, add the remaining monomer mixture dropwise to the reaction flask through a constant pressure dropping funnel. After the addition is complete, maintain the temperature and react for another 30 min. Cool to room temperature to obtain an aqueous dispersion of copolymer nanoparticles with a particle size of approximately 35 nm.

[0046] The above copolymer nanoparticle dispersion was diluted with water to 3.0 wt%. This dispersion, along with a 2.0 wt% aqueous dispersion of titanium dioxide nanoparticles with a particle size of approximately 25 nm, was alternately coated three times on a silicon wafer surface using spin-coating technology to prepare a one-dimensional photonic crystal with a thickness of approximately 500 nm. The one-dimensional photonic crystal was sealed in a closed container containing saturated ethanol vapor for 2 minutes. After being removed from the container, it was heated on a 100°C hot plate for 5 minutes. After the photonic crystal cooled, a perforated mask was tightly adhered to its surface. A 0.1 M Na₂CO₃ aqueous solution was dropped onto the sample surface. After 30 seconds, the surface was rinsed with deionized water, and the moisture on the photonic crystal surface was dried. After removing the mask, the photonic crystal time-temperature indicator device was obtained.

[0047] Examples 7-10

[0048] The method is the same as in Example 6, but the alkaline treatment conditions are as follows: 0.1M Na2CO3 aqueous solution treatment for 30s, 0.1M Na2CO3 aqueous solution treatment for 90s, 0.01M Na2CO3 aqueous solution treatment for 60s, and 0.1M NaHCO3 aqueous solution treatment for 30s.

[0049] Example 11

[0050] Weigh 1.0 g of acrylic acid and 10.0 g of methyl methacrylate and mix them thoroughly. Dissolve 1.0 g of hexadecyltrimethylammonium bromide in 40 mL of deionized water and add it to a 150 mL three-necked flask. Add 2.0 g of the above monomer mixture to the reaction flask. Under nitrogen protection and stirring at 400 rpm, heat to 75 °C and stir for 20 min. Then add 4 mL of an aqueous solution containing 75 mg of potassium persulfate. After reacting for 20 min, add the remaining monomer mixture dropwise to the reaction flask through a constant pressure dropping funnel. After the addition is complete, maintain the temperature and react for another 30 min. Cool to room temperature to obtain an aqueous dispersion of copolymer nanoparticles with a particle size of approximately 40 nm.

[0051] The above copolymer nanoparticle dispersion was diluted with water to 3.0 wt%. This dispersion, along with a 2.0 wt% aqueous dispersion of titanium dioxide nanoparticles with a particle size of approximately 25 nm, was alternately coated three times on the surface of a polyethylene terephthalate (PET) plate using spin-coating technology to prepare a flexible one-dimensional photonic crystal with a thickness of approximately 500 nm. The one-dimensional photonic crystal was sealed in a closed container containing saturated ethanol vapor for 2 minutes. After being removed from the container, it was heated on a 100°C hot plate for 5 minutes. After the photonic crystal cooled, a perforated mask sticker was tightly adhered to the surface of the photonic crystal. A 0.1 M Na₂CO₃ aqueous solution was dropped onto the sample surface. After 30 seconds, the sample was rinsed with deionized water, and the surface moisture was dried. After removing the mask, the photonic crystal time-temperature indicator device was obtained.

[0052] Examples 12-15

[0053] The method is the same as in Example 11, but the substrates used to assemble the one-dimensional photonic crystal are polyethylene terephthalate film, polystyrene plate, polystyrene film, and polydimethylsiloxane film, respectively.

[0054] Example 16

[0055] Weigh 1.0 g of methacrylic acid and 10.0 g of butyl methacrylate and mix them thoroughly. Dissolve 1.0 g of hexadecyltrimethylammonium bromide in 40 mL of deionized water and add it to a 150 mL three-necked flask. Add 2.0 g of the above monomer mixture to the reaction flask. Under nitrogen protection and stirring at 400 rpm, heat to 75 °C and stir for 20 min. Then add 4 mL of an aqueous solution containing 75 mg of potassium persulfate. After reacting for 20 min, add the remaining monomer mixture dropwise to the reaction flask through a constant pressure dropping funnel. After the addition is complete, maintain the temperature and react for another 30 min. Cool to room temperature to obtain an aqueous dispersion of copolymer nanoparticles with a particle size of approximately 50 nm.

[0056] The above copolymer nanoparticle dispersion was diluted with water to 3.0 wt%. This dispersion, along with a 2.0 wt% aqueous dispersion of zirconium dioxide nanoparticles with a particle size of approximately 40 nm, was alternately coated three times on a silicon wafer surface using spin-coating technology to prepare a one-dimensional photonic crystal with a thickness of approximately 500 nm. The one-dimensional photonic crystal was sealed in a closed container containing saturated ethanol vapor for 2 minutes. After being removed from the container, it was heated on a 100°C hot plate for 5 minutes. After the photonic crystal cooled, a perforated mask was tightly adhered to its surface. A 0.1 M Na₂CO₃ aqueous solution was dropped onto the sample surface. After 30 seconds, the surface was rinsed with deionized water, and the moisture on the photonic crystal surface was dried. After removing the mask, the photonic crystal time-temperature indicator device was obtained.

[0057] Examples 17-20

[0058] The method is the same as in Example 16, but the substrates used to assemble the one-dimensional photonic crystal are polyethylene terephthalate film, polystyrene plate, polystyrene film, and polydimethylsiloxane film, respectively.

[0059] Example 21

[0060] Weigh 1.0 g of acrylic acid and 10.0 g of butyl methacrylate and mix them thoroughly. Dissolve 1.0 g of hexadecyltrimethylammonium bromide in 40 mL of deionized water and add it to a 150 mL three-necked flask. Add 2.0 g of the above monomer mixture to the reaction flask. Under nitrogen protection and stirring at 400 rpm, heat to 75 °C and stir for 20 min. Then add 4 mL of an aqueous solution containing 75 mg of potassium persulfate. After reacting for 20 min, add the remaining monomer mixture dropwise to the reaction flask through a constant pressure dropping funnel. After the addition is complete, maintain the temperature and react for another 30 min. Cool to room temperature to obtain an aqueous dispersion of copolymer nanoparticles with a particle size of approximately 50 nm.

[0061] The above copolymer nanoparticle dispersion was diluted with water to 3.0 wt%. This dispersion, along with a 2.0 wt% aqueous dispersion of zirconium dioxide nanoparticles with a particle size of approximately 40 nm, was alternately coated three times on a silicon wafer surface using spin-coating technology to prepare a one-dimensional photonic crystal with a thickness of approximately 500 nm. The one-dimensional photonic crystal was sealed in a closed container containing saturated ethanol vapor for 2 minutes. After being removed from the container, it was heated on a 100°C hot plate for 5 minutes. After the photonic crystal cooled, a perforated mask was tightly adhered to its surface. A 0.1 M Na₂CO₃ aqueous solution was dropped onto the sample surface. After 30 seconds, the surface was rinsed with deionized water, and the moisture on the photonic crystal surface was dried. After removing the mask, the photonic crystal time-temperature indicator device was obtained.

[0062] Examples 22-25

[0063] The method is the same as in Example 21, but the concentrations of the copolymer aqueous dispersions used to assemble the one-dimensional photonic crystals are 1.0 wt%, 2.0 wt%, 3.5 wt%, and 4.0 wt%, respectively.

Claims

1. A photonic crystal time-temperature indicating thin-film device, the time-temperature indicating thin-film device comprising a substrate and an indicating thin film attached thereon, The indicator film is prepared by treating the central region of a one-dimensional photonic crystal film with an alkaline aqueous solution; The one-dimensional photonic crystal thin film is formed by alternating stacks of disordered inorganic nanoparticle layers and disordered copolymer nanoparticle layers on a substrate, wherein... The inorganic nanoparticles are one of titanium dioxide, zirconium dioxide, zinc oxide, and aluminum oxide; the copolymer nanoparticles are prepared by microemulsion polymerization of hydrophobic polymeric monomers and carboxyl-containing polymeric monomers, with a feeding ratio of hydrophobic polymeric monomers to carboxyl-containing polymeric monomers of 30:1 to 3:

1. The hydrophobic polymeric monomers are one of methyl methacrylate, styrene, methyl acrylate, ethyl methacrylate, and butyl methacrylate; the carboxyl-containing polymeric monomers are one of acrylic acid, methacrylic acid, 2-ethylacrylic acid, 2-propylacrylic acid, and 3-butenoic acid.

2. The device according to claim 1, characterized in that: The alkaline aqueous solution is one of sodium carbonate, sodium bicarbonate, sodium hydroxide, potassium carbonate, and potassium bicarbonate aqueous solution, and the concentration of the aqueous solution is 0.001~5 M.

3. The device according to claim 2, characterized in that: The concentration of the aqueous solution is 0.01~0.1 M.

4. The device according to claim 1, characterized in that: The central region of the one-dimensional photonic crystal thin film is treated in an alkaline aqueous solution for 1 to 300 seconds.

5. The device according to claim 4, characterized in that: The central region of the one-dimensional photonic crystal thin film is treated in an alkaline aqueous solution for 20-120 seconds.

6. The device according to claim 1, characterized in that: The alkaline treatment of the central region of the one-dimensional photonic crystal thin film is achieved with the assistance of a perforated mask.

7. The device according to claim 1, characterized in that: The substrates used for assembling one-dimensional photonic crystals include one of the following: silicon wafers, glass, polyethylene terephthalate boards, polyethylene terephthalate films, polystyrene boards, polystyrene films, and polydimethylsiloxane films.

8. The device according to claim 1, characterized in that: The ratio of the hydrophobic polymeric monomer to the carboxyl-containing polymeric monomer is 15:1 to 8:

1.

9. A method for fabricating the photonic crystal time-temperature indicating thin-film device according to any one of claims 1 to 8, characterized in that: The process includes the following steps: ① Copolymer nanoparticles were prepared using microemulsion polymerization; ② The prepared copolymer nanoparticles and inorganic nanoparticles are alternately stacked on the substrate surface by a layer-by-layer self-assembly method to prepare a one-dimensional photonic crystal thin film. ③ Place the one-dimensional photonic crystal in a sealed container containing saturated ethanol vapor for 1 min, so that the copolymer nanoparticles can be connected to form a film through swelling and deswelling, thereby enhancing the structural stability of the film. ④ Heat the one-dimensional photonic crystal thin film after step ③ at 50~150℃ for 1~20 min; ⑤ The perforated mask is tightly attached to the surface of the one-dimensional photonic crystal. Alkali solution is dropped onto the surface of the photonic crystal. The exposed area is soaked in the alkali solution, while the mask-protected area does not come into contact with the alkali solution. ⑥ Rinse off the alkaline solution on the surface of the one-dimensional photonic crystal thin film with deionized water, blow off the surface moisture, and remove the mask to obtain the photonic crystal time-temperature indicator thin film device.

10. The method according to claim 9, characterized in that: The one-dimensional photonic crystal thin film after step ③ is heated at 80~100℃ for 3~10 min.

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