Physical Unclonable Anti-Counterfeiting Structure Based on Bionic Nanostructure and Its Applications

Abstract

The present invention relates to the field of anti-counterfeiting technology, and in particular to a physically unclonable anti-counterfeiting structure based on biomimetic nanostructures and its applications. The structure comprises a substrate; a biomimetic nanostructure layer is disposed on the substrate; the biomimetic nanostructure layer comprises anisotropic flaky nanostructures and isotropic columnar nanostructures, which are arranged in a random multimodal manner on the same plane. This anti-counterfeiting structure, through the synergistic system of anisotropic flaky nanostructures and isotropic columnar nanostructures, addresses the problem of traditional anti-counterfeiting technologies, which suffer from the single nature and susceptibility to duplication.

Description

Technical Field

[0001] The present invention relates to the field of anti-counterfeiting technology, and in particular to a physical unclonable anti-counterfeiting structure based on a bionic nanostructure and its application. Background Art

[0002] With the development of the commodity economy, anti-counterfeiting technology has become a crucial means of protecting brand value and consumer rights. While traditional anti-counterfeiting technologies (such as watermarks, holograms, and QR codes) are widely used, their security features are susceptible to high-precision duplication or tampering, making them insufficiently secure for high-end applications. Physically unclonable fabrication (PUF) technology has become a hot topic in anti-counterfeiting research, as it leverages the physical properties of materials to generate unique and unpredictable identifiers. This eliminates the need for additional encrypted storage, significantly improving anti-counterfeiting security. However, existing PUF technologies often rely on complex photolithography and nanoimprinting processes, resulting in high fabrication costs and long production cycles. Furthermore, some structures, such as silicon-based PUFs, are incompatible with flexible substrates, limiting their widespread application in packaging and labeling. Existing silicon-based PUF structures can cost as much as $200-500 per square centimeter and are inherently unbendable (fractures occur at bend radii greater than 10 cm), severely limiting their application in flexible packaging. Consequently, solutions are urgently needed. Summary of the Invention

[0003] The technical problem to be solved by the present invention is to provide a physical unclonable anti-counterfeiting structure and application based on bionic nanostructures. The anti-counterfeiting structure solves the problem that traditional anti-counterfeiting technology has a single feature and is easy to copy through a synergistic system of anisotropic flaky nanostructures and isotropic columnar nanostructures.

[0004] To achieve the above-mentioned purpose, the technical solution of the present invention is implemented as follows: a physically unclonable anti-counterfeiting structure based on a bionic nanostructure includes a substrate; a bionic nanostructure layer is provided on the substrate; the bionic nanostructure layer is a combination of anisotropic lamellar nanostructures and isotropic columnar nanostructures.

[0005] There are many options for arranging anisotropic lamellar nanostructures and isotropic columnar nanostructures, which can be weighed according to actual needs and ease of processing.

[0006] Preferably, the thickness of the biomimetic nanostructure layer is 120nm-320nm. The period and height of the anisotropic flaky nanostructure and the isotropic columnar nanostructure can have various degrees, which can be selected according to the anti-counterfeiting needs to obtain a variety of different effects.

[0007] Preferably, the substrate is PI or quartz glass, and the substrate is a flexible PI film that is compatible with a rigid substrate or a flexible substrate.

[0008] Preferably, the anisotropic lamellar nanostructures and the isotropic columnar nanostructures are arranged in a random multimodal manner on the same plane.

[0009] Preferably, the random multimodal manner includes one or both of an adjustment arrangement manner and a proportional relationship manner.

[0010] The arrangement can be adjusted by changing the polarization characteristics of the laser (i.e. the scanning direction): when the laser scans unidirectionally, the anisotropic nanosheet structure is always perpendicular to the laser scanning direction. The scanning direction of the laser can be changed to make the sheet structure distributed in different directions.

[0011] Preferably, the material used for the bionic nanostructure layer is polyimide.

[0012] Preferably, the anisotropic flaky nanostructure is formed by unidirectionally scanning an ultraviolet laser along the X-axis of the substrate surface and then peeling off, and the column spacing of the flaky structures in the anisotropic flaky nanostructure is 100-240 nm and the height is 120-260 nm.

[0013] One-way scanning: The scanning method is to ensure that the spot length can completely cover the circular hole pattern in the mask during scanning, use a uniform laser energy density and laser irradiation times, and ensure that the laser scanning is always in the same direction during scanning.

[0014] The anisotropic flaky nanostructure formed by peeling after unidirectional scanning exists on the surface of both the quartz glass substrate and the PI film after peeling, and can form a physical backup.

[0015] Preferably, the isotropic columnar nanostructure is prepared by bidirectional scanning of an ultraviolet laser along the X-axis and Y-axis of the substrate surface, and the column diameter of the isotropic columnar nanostructure is in the range of 40-45 nm, the height is 160-320 nm, and the period (i.e., the center distance between adjacent columns) is 70-130 nm.

[0016] Bidirectional scanning: After the laser scans once in the X-axis or Y-axis direction, the platform controls the sample to rotate 90° to scan in the other direction, and then returns to the original position to scan, alternating until the PI film is completely bubbled and separated from the quartz glass substrate.

[0017] The isotropic columnar nanostructure formed by peeling after bidirectional scanning exists on the surface of both the quartz glass substrate and the PI film, which can form a physical backup.

[0018] Preferably, the rigid substrate is one of a quartz glass substrate and a silicon wafer, and the flexible substrate is one of PI, PDMS, and PVA.

[0019] Preferably, the anti-counterfeiting structure is used for article anti-counterfeiting.

[0020] (1) A layer of metal Pt is plated on the surface of the anti-counterfeiting structure, and the anti-counterfeiting structure will appear transparent black, which has a significant light-transmitting effect compared to the opaque silver on the smooth surface;

[0021] (2) The anti-counterfeiting structure has different reflectivity under 400nm s-polarized light at 60° oblique incidence; this result can be measured using a UV-visible spectrophotometer;

[0022] (3) Backup cross-validation: The surface nanostructure distribution of the anti-counterfeiting structure is observed by scanning electron microscopy, and the similarity between the anti-counterfeiting structure and the backup structure is compared.

[0023] The beneficial effects of the present invention are embodied in:

[0024] (1) The anti-counterfeiting structure provided by the present invention is unclonable: the synergistic effect of the random morphology of the bionic nanostructure and the hybrid structure makes the anti-counterfeiting feature difficult to be accurately copied. PUF (Physical unclonable function) is a physical object with intrinsic, unique, fingerprint-like characteristics, which is unclonable by definition. Its uniqueness is provided by a random pattern, which is based on the random disorder of the microstructure of the object during the manufacturing process. By definition, it is easy to produce and easy to read, but even the manufacturer cannot clone it, nor can it be predicted. Because the light intensity of the ultraviolet nanosecond laser is Gaussian, this bionic nanostructure has a random special morphology distribution, and the height and period are random and unpredictable during the preparation process. The nanostructure prepared by laser lift-off technology cannot be cloned or predicted even by the manufacturer, and has a unique special nanostructure morphology, thereby generating low-cost, high-reliability PUF features.

[0025] (2) The preparation of the anti-counterfeiting structure provided by the present invention is low-cost and scalable: the laser scanning process (e.g., preparation of a 15×15 mm² area within 1 minute) is much cheaper than traditional nano-processing.

[0026] (3) The anti-counterfeiting structure provided by the present invention is compatible with flexible substrates (PI, PDMS, PVA), suitable for wearable devices, packaging and other fields, and has adaptability to multiple scenarios.

[0027] (4) The anti-counterfeiting structure provided by the present invention is formed into a bionic columnar or sheet-like nanostructure in the same nanostructure layer through process control, which has both randomness and controllability.

[0028] (5) The anti-counterfeiting structure provided by the present invention has a multiple anti-counterfeiting verification system: ① A layer of metal Pt is plated on the surface of the anti-counterfeiting structure, and the anti-counterfeiting structure appears to be translucent black, which has a significant light-transmitting effect compared to the silver color of the smooth surface that is opaque; ② The anti-counterfeiting structure has different reflectivity under 60° oblique incidence of 400nm s-polarized light; this result can be tested using a UV-visible spectrophotometer; ③ Backup cross-validation: The surface nanostructure morphology distribution of the anti-counterfeiting structure is observed by scanning electron microscopy, and the similarity between the anti-counterfeiting structure and the backup structure is compared. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 This is a schematic diagram of the physical unclonable anti-counterfeiting structure based on bionic nanostructures of the present invention;

[0030] Figure 2 1 is a schematic diagram of the preparation process of the bionic nanostructure of the present invention;

[0031] Figure 3 It is a schematic diagram of the laser scanning method of the present invention;

[0032] Figure 4 This is a photo of the quartz glass and PI with anisotropic flaky nanostructures and the quartz glass and PI with isotropic columnar nanostructures attached to a black adsorption box.

[0033] Figure 5 These are optical photographs of samples with nanostructured areas (transparent) and unstructured areas (metallic color) after depositing metal Pt according to the present invention;

[0034] Figure 6 This is a comparison chart of the reflectivity of the nanostructured quartz glass of the present invention and the original quartz glass substrate in the visible light band at an incident angle of 60° for s-polarized light;

[0035] Figure 7 These are the SEM morphology images and AFM images of the anisotropic flaky nanostructures of the present invention;

[0036] Figure 8 These are the SEM morphology images and AFM images of the isotropic columnar nanostructures of the present invention;

[0037] Figure 9 This is a comparison of the microscopic morphologies of the anisotropic sheet-like nanostructure and the backup structure of the present invention;

[0038] Figure 10 This is a comparison of the microscopic morphologies of the isotropic columnar nanostructure and the backup structure of the present invention;

[0039] Figure 11 It is a schematic structural diagram of the NJUPT anti-counterfeiting mark containing two nanostructures according to the present invention.

[0040] Figure 12 This is a graph showing the change in the nanocolumn morphology along with the laser scanning direction.

[0041] Reference numerals and descriptions:

[0042] 1. Substrate; 2. Bionic nanostructure layer; 3. Anisotropic lamellar nanostructure; 4. Isotropic columnar nanostructure. DETAILED DESCRIPTION

[0043] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of the embodiments. In the absence of conflict, the embodiments in this application and the features in the embodiments can be combined with each other. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0044] like Figures 1-12 As shown, the present invention provides a physical unclonable anti-counterfeiting structure based on a bionic nanostructure. In the present invention, the substrate 1 used for the anti-counterfeiting structure can be a rigid quartz glass or a flexible PI film. When the substrate 1 of the anti-counterfeiting structure is made of a flexible PI film, it is compatible with rigid substrates and flexible substrates.

[0045] The preparation method of the biomimetic nanostructured layer in the present invention is as follows: spin-coating and curing a PI film on a glass substrate to a thickness of approximately 20µm; scanning the side of the glass substrate to which the PI film is not attached with an ultraviolet laser, with process parameters controlled during scanning: energy density of 80-98mJ / cm², 100-460 scans for unidirectional APN, and 37-62 cross-scans for bidirectional X-axis and Y-axis, so that nanoscale cavitation occurs at the interface of the PI film in the laser scanning area, causing the interface to reach a sub-peeling state, at which point nanofibers form a connection between the PI film and the glass substrate; flatly affixing a thermal release tape to the PI film; and peeling the PI film from the glass substrate with the aid of external force using the thermal release tape.

[0046] Example 1

[0047] like Figure 4 The optical photograph of a quartz glass having anisotropic flaky nanostructures 3 according to this embodiment is shown. The optical photograph includes a substrate 1 made of quartz glass and anisotropic flaky nanostructures 3 on the substrate 1. Anisotropic flaky nanostructures 3 are material structures with a flaky appearance at the nanoscale and exhibiting different physical properties in different directions. Through a specific preparation method, the material is precisely controlled to nanoscale dimensions and formed into a columnar morphology.

[0048] The substrate 1 made of quartz glass has an area of 2 cm*2 cm and a thickness of 0.5 mm. The thickness of the anisotropic sheet-like nanostructure 3 is 120 nm-150 nm. The material used to make the anisotropic sheet-like nanostructure 3 is polyimide.

[0049] The anisotropic sheet-like nanostructure 3 of this embodiment is prepared by the following process: Figure 2 (a):

[0050] A PI film was spin-coated and cured on a glass substrate to a thickness of approximately 20 µm. The specific operation and experimental parameters are as follows:

[0051] 1. Fix the glass substrate on the vacuum suction cup of the glue roller and apply an appropriate amount of 5000cp viscosity PI solution in the middle;

[0052] 2. Spin coating parameters are 400r / min*10s (acceleration 300) + 1000r / min*30s (acceleration 800);

[0053] 3. Leveling: Let the film stand for 60~90s;

[0054] 4. Soft baking: Place the sheet on a hot plate and heat at 120°C for 3 minutes;

[0055] 5. PI curing: Use gradient temperature to heat and cure PI, with the temperature and time set as 140℃*30 minutes + 200℃*30 minutes + 300℃*90 minutes;

[0056] Use ultraviolet laser to scan the side of the glass substrate without PI film attached. The process parameters during scanning are: laser energy density 89mj / cm 2 The number of laser scans was 100 times, and the laser scanning direction was unidirectional (along the X-axis), which caused nanoscale cavitation at the interface of the PI film in the laser scanning area, so that the interface reached a sub-peeling state. At this time, nanofiber connection was generated at the interface between the PI film and the glass substrate.

[0057] A heat release tape is evenly pasted on the PI film. The heat release tape here serves as an external force to assist in peeling the PI film from the glass substrate.

[0058] The heat release tape was heated at 110°C to complete the heat release process of the PI film, thereby preparing quartz glass and PI film with anisotropic flaky nanostructure 3 surfaces.

[0059] After the PI film is peeled off, the process parameters are: laser energy density is 89mj / cm 2, the laser scanning times were 100 times, and the laser scanning direction was unidirectional (along the X axis). The sample (quartz glass with anisotropic flake nanostructure 3 and PI film) was attached to a black adsorption box (such as Figure 4 As shown, a is a quartz glass substrate, b is a PI film substrate).

[0060] Example 2

[0061] like Figure 4 As shown, an optical photograph of a quartz glass having anisotropic flaky nanostructures 3 according to this embodiment includes a substrate 1 made of quartz glass and the anisotropic flaky nanostructures 3 on the substrate 1. The quartz glass substrate 1 has an area of 2 cm*2 cm and a thickness of 0.5 mm. The anisotropic flaky nanostructures 3 have a thickness of 190 nm-210 nm. The material making the anisotropic flaky nanostructures 3 is polyimide.

[0062] The anisotropic sheet-like nanostructure 3 of this embodiment is prepared by the following process: Figure 2 (a):

[0063] A PI film was spin-coated and cured on a glass substrate to a thickness of approximately 20 µm. The specific operation and experimental parameters are as follows:

[0064] 1. Fix the glass substrate on the vacuum suction cup of the glue roller and apply an appropriate amount of 5000cp viscosity PI solution in the middle;

[0065] 2. Spin coating parameters are 400r / min*10s (acceleration 300) + 1000r / min*30s (acceleration 800);

[0066] 3. Leveling: Let the film stand for 60~90s;

[0067] 4. Soft baking: Place the sheet on a hot plate and heat at 120°C for 3 minutes;

[0068] 5. PI curing: Use gradient temperature to heat and cure PI, with the temperature and time set as 140℃*30 minutes + 200℃*30 minutes + 300℃*90 minutes;

[0069] Use ultraviolet laser to scan the side of the glass substrate without PI film attached. The process parameters during scanning are: laser energy density 89mj / cm 2 The laser scans were performed 340 times in a unidirectional direction (along the X-axis), causing nanoscale cavitation at the interface of the PI film in the laser scanning area, bringing the interface to a sub-peeling state. At this point, nanofiber connections were generated at the interface between the PI film and the glass substrate.

[0070] Attach a heat release tape evenly to the PI film. The heat release tape acts as an external force to help peel the PI film from the glass substrate.

[0071] The heat release tape was heated at 110°C to complete the heat release process of the PI film, thereby preparing quartz glass and PI film with anisotropic flaky nanostructure 3 surfaces.

[0072] Example 3

[0073] like Figure 4 As shown, an optical photograph of a quartz glass having anisotropic flaky nanostructures 3 according to this embodiment includes a substrate 1 made of quartz glass and the anisotropic flaky nanostructures 3 on the substrate 1. The quartz glass substrate 1 has an area of 2 cm*2 cm and a thickness of 0.5 mm. The anisotropic flaky nanostructures 3 have a thickness of 140 nm-280 nm. The material used to make the anisotropic flaky nanostructures 3 is polyimide.

[0074] The anisotropic sheet-like nanostructure 3 of this embodiment is prepared by the following process: Figure 2 (a):

[0075] A PI film was spin-coated and cured on a glass substrate to a thickness of approximately 20 µm. The specific operation and experimental parameters are as follows:

[0076] 1. Fix the glass substrate on the vacuum suction cup of the glue roller and apply an appropriate amount of 5000cp viscosity PI solution in the middle;

[0077] 2. Spin coating parameters are 400r / min*10s (acceleration 300) + 1000r / min*30s (acceleration 800);

[0078] 3. Leveling: Let the film stand for 60~90s;

[0079] 4. Soft baking: Place the sheet on a hot plate and heat at 120°C for 3 minutes;

[0080] 5. PI curing: Use gradient temperature to heat and cure PI, with the temperature and time set as 140℃*30 minutes + 200℃*30 minutes + 300℃*90 minutes;

[0081] Use ultraviolet laser to scan the side of the glass substrate without PI film attached. The process parameters during scanning are: laser energy density 89mj / cm 2 The laser scans were performed 460 times in a unidirectional direction (along the X-axis), causing nanoscale cavitation at the interface of the PI film in the laser scanning area, bringing the interface to a sub-peeling state. At this point, nanofiber connections were formed at the interface between the PI film and the glass substrate.

[0082] Attach a heat release tape evenly to the PI film. The heat release tape acts as an external force to help peel the PI film from the glass substrate.

[0083] The heat release tape was heated at 110°C to complete the heat release process of the PI film, thereby preparing quartz glass and PI film with anisotropic flaky nanostructure 3 surfaces.

[0084] The anisotropic sheet-like nanostructure 3 of Examples 1, 2, and 3 above was characterized;

[0085] See also Figure 8 Scanning electron microscopy and atomic force microscopy characterization of the anisotropic flaky nanostructures 3 of Examples 1, 2, and 3 revealed that the anisotropic flaky nanostructures 3 on the surface of substrate 1 were distributed in columns, with the distance between each column clearly visible. The period and height distribution of the entire structure were random, allowing it to be used to construct physically unclonable anti-counterfeiting elements.

[0086] Applying the processed anisotropic sheet-like nanostructure 3 to anti-counterfeiting of articles comprises the following steps:

[0087] (1) If Figure 5 The first level of anti-counterfeiting verification is performed as shown: a layer of metal Pt is plated on the surface of the quartz glass and PI film with (flake / columnar) nanostructures. The area with the nanostructure will appear transparent black, which has a significant light-transmitting effect compared to the silver-colored smooth surface that is opaque. If this phenomenon occurs, proceed to step (2). If this effect does not occur, it is judged to be false.

[0088] (2) If Figure 6 As shown in (d) (the naming convention of the curve legend in the figure is: s-light oblique incident angle - glass placement angle), the second anti-counterfeiting verification is carried out using a UV-visible spectrophotometer. The glass with anisotropic flake nanostructures 3 has a large difference in reflectivity under oblique incidence of s-polarized light in different directions; compared with the original quartz glass substrate ( Figure 6 (b)) shows obvious differences. If such results are found by UV-Vis spectrophotometry, proceed to step (3).

[0089] (3) The third level of anti-counterfeiting verification: Figure 7 The results are shown in Figure 2. SEM and AFM were used to observe the

[0090] And extract the information of shape height, diameter (width), spacing, etc. Figure 9 As shown, the surface morphology data of the sample and the backup structure are processed and data matching is performed. If the matching results are consistent, it is true, and if the results do not match, it is false.

[0091] During the specific verification, if the anti-counterfeiting is true, it is necessary to go through the above three steps for verification. If the anti-counterfeiting is false, you can follow the steps during the verification and terminate if a false situation occurs.

[0092] Example 4

[0093] like Figure 4 Figure 2 shows an optical photograph of a quartz glass substrate 1 having isotropic columnar nanostructures 4 according to this embodiment. The photograph includes a substrate 1 made of quartz glass and the isotropic columnar nanostructures 4 formed on the substrate 1. Isotropic columnar nanostructures 4 are material structures that have a columnar shape at the nanoscale and exhibit the same physical properties in different directions. These structures are typically prepared using specific methods to precisely control the material's size at the nanoscale and form a columnar morphology.

[0094] The quartz glass substrate has an area of 2 cm*2 cm and a thickness of 0.5 mm. The thickness of the isotropic columnar nanostructure 4 is 200-220 nm and the material is polyimide.

[0095] The isotropic columnar nanostructure 4 of this embodiment is prepared by the following process: Figure 2 (b):

[0096] A PI film was spin-coated and cured on a glass substrate to a thickness of approximately 20 µm. The specific operation and experimental parameters are as follows:

[0097] 1. Fix the glass substrate on the vacuum suction cup of the glue roller and apply an appropriate amount of 5000cp viscosity PI solution in the middle;

[0098] 2. Spin coating parameters are 400r / min*10s (acceleration 300) + 1000r / min*30s (acceleration 800);

[0099] 3. Leveling: Let the film stand for 60~90s;

[0100] 4. Soft baking: Place the sheet on a hot plate and heat at 120°C for 3 minutes;

[0101] 5. PI curing: Use gradient temperature to heat and cure PI, with the temperature and time set as 140℃*30 minutes + 200℃*30 minutes + 300℃*90 minutes;

[0102] Use ultraviolet laser to scan the side of the glass substrate without PI film attached. The process parameters are controlled as follows: laser energy density is 89mj / cm 2The laser scans 37 times along the X-axis and Y-axis cross-scans, and the laser scanning direction is bidirectional (X-axis and Y-axis cross-scans), causing nanoscale cavitation at the PI interface in the laser scanning area, bringing the interface to a sub-peeling state. At this time, nanofiber connections are generated at the interface between the PI film and the glass substrate;

[0103] Attach a heat release tape evenly to the PI film. The heat release tape acts as an external force to help peel the PI film from the glass substrate.

[0104] The heat release tape was heated at 110°C to complete the heat release process of the PI film, thereby preparing a quartz glass and PI film with an isotropic columnar nanostructure 4 surface.

[0105] Example 5

[0106] like Figure 4 As shown, an optical photograph of a quartz glass having an isotropic columnar nanostructure 4 according to this embodiment includes a substrate 1 made of quartz glass and the isotropic columnar nanostructure 4 on the substrate 1. The quartz glass substrate has an area of 2 cm*2 cm and a thickness of 0.5 mm. The thickness of the isotropic columnar nanostructure 4 is 280-320 nm and the material is polyimide.

[0107] The isotropic columnar nanostructure 4 of this embodiment is prepared by the following process: Figure 2 (b):

[0108] A PI film was spin-coated and cured on a glass substrate to a thickness of approximately 20 µm. The specific operation and experimental parameters are as follows:

[0109] 1. Fix the glass substrate on the vacuum suction cup of the glue roller and apply an appropriate amount of 5000cp viscosity PI solution in the middle;

[0110] 2. Spin coating parameters are 400r / min*10s (acceleration 300) + 1000r / min*30s (acceleration 800);

[0111] 3. Leveling: Let the film stand for 60~90s;

[0112] 4. Soft baking: Place the sheet on a hot plate and heat at 120°C for 3 minutes;

[0113] 5. PI curing: Use gradient temperature to heat and cure PI, with the temperature and time set as 140℃*30 minutes + 200℃*30 minutes + 300℃*90 minutes;

[0114] Use ultraviolet laser to scan the side of the glass substrate without PI film attached. The process parameters are controlled as follows: laser energy density is 89mj / cm 2The laser scans 51 times along the X-axis and Y-axis cross-scans, and the laser scanning direction is bidirectional (X-axis and Y-axis cross-scans), which causes nanoscale cavitation at the PI interface in the laser scanning area, bringing the interface to a sub-peeling state. At this time, nanofiber connections are generated at the interface between the PI film and the glass substrate;

[0115] Attach a heat release tape evenly to the PI film. The heat release tape acts as an external force to help peel the PI film from the glass substrate.

[0116] The heat release tape was heated at 110°C to complete the heat release process of the PI film, thereby preparing a quartz glass and PI film with an isotropic columnar nanostructure 4 surface.

[0117] After the PI film is peeled off, the process parameters are: laser energy density is 89mj / cm 2 The laser scanning times are X51-Y51 times, and the laser scanning direction is bidirectional (X-axis-Y-axis cross). The quartz glass with isotropic columnar nanostructures 4 and the PI film are attached to the black adsorption box (such as Figure 4 As shown, c is a quartz glass substrate, d is a PI film substrate).

[0118] Example 6

[0119] like Figure 4 As shown, an optical photograph of a quartz glass having an isotropic columnar nanostructure 4 according to this embodiment includes a substrate 1 made of quartz glass and the isotropic columnar nanostructure 4 on the substrate 1. The quartz glass substrate has an area of 2 cm*2 cm and a thickness of 0.5 mm. The thickness of the isotropic columnar nanostructure 4 is 160-220 nm and the material is polyimide.

[0120] The isotropic columnar nanostructure 4 of this embodiment is prepared by the following process: Figure 2 (b):

[0121] A PI film was spin-coated and cured on a glass substrate to a thickness of approximately 20 µm. The specific operation and experimental parameters are as follows:

[0122] 1. Fix the glass substrate on the vacuum suction cup of the glue roller and apply an appropriate amount of 5000cp viscosity PI solution in the middle;

[0123] 2. Spin coating parameters are 400r / min*10s (acceleration 300) + 1000r / min*30s (acceleration 800);

[0124] 3. Leveling: Let the film stand for 60~90s;

[0125] 4. Soft baking: Place the sheet on a hot plate and heat at 120°C for 3 minutes;

[0126] 5. PI curing: Use gradient temperature to heat and cure PI, with the temperature and time set as 140℃*30 minutes + 200℃*30 minutes + 300℃*90 minutes;

[0127] Use ultraviolet laser to scan the side of the glass substrate without PI film attached. The process parameters are controlled as follows: laser energy density is 89mj / cm 2 The laser scanning times are 62 times along the X-axis-Y-axis cross scanning, and the laser scanning direction is bidirectional (X-axis-Y-axis cross), which causes nanoscale cavitation at the PI interface in the laser scanning area, bringing the interface to a sub-peeling state. At this time, nanofiber connection is generated at the interface between the PI film and the glass substrate.

[0128] A heat release tape is evenly pasted on the PI film; the heat release tape here serves as an external force to assist in peeling the PI film from the glass substrate.

[0129] The heat release tape was heated at 110°C to complete the heat release process of the PI film, thereby preparing a quartz glass and PI film with an isotropic columnar nanostructure 4 surface.

[0130] The isotropic columnar nanostructures 4 of Examples 4, 5, and 6 were characterized.

[0131] The isotropic columnar nanostructures 4 of Examples 4, 5, and 6 were characterized by scanning electron microscopy and atomic force microscopy ( Figure 9 ), it can be observed that the period and height distribution of the structure are random, which fully proves that the structure cannot be cloned.

[0132] The isotropic columnar nanostructure 4 processed in specific embodiments 4, 5, and 6 is applied to anti-counterfeiting of articles, including the following steps:

[0133] (1) If Figure 5 The first level of anti-counterfeiting verification is performed as shown below: a layer of metal Pt is plated on the surface of quartz glass and PI film with (flake / columnar) nanostructures. The areas with the nanostructures will appear translucent black, which has a significant light-transmitting effect compared to the opaque silver surface. If this phenomenon occurs, proceed to step (2). If this effect is not seen, the product is judged to be fake.

[0134] (2) If Figure 6 As shown in (c) (the naming convention of the curve legend in the figure is: s-light oblique incident angle - glass placement angle), the third anti-counterfeiting verification is carried out using a UV-visible spectrophotometer: the glass with isotropic columnar nanostructures 4 has a large difference in reflectivity under oblique incidence of s-polarized light in different directions; compared with the original quartz glass substrate ( Figure 6(b)) show obvious differences. If such results are found by UV-Vis spectrophotometry, proceed to step (3).

[0135] (3) The fourth level of anti-counterfeiting verification: Figure 8 The results are shown in Figure 2. SEM and AFM were used to observe the

[0136] And extract the information of shape height, spacing, etc. Figure 10 As shown, the surface morphology data of the sample and the backup structure are processed and data matching is performed. If the matching results are consistent, it is true, and if the results do not match, it is false.

[0137] During the specific verification, if the anti-counterfeiting is true, it is necessary to go through the above three steps for verification. If the anti-counterfeiting is false, you can follow the steps during the verification and terminate if a false situation occurs.

[0138] Example 7

[0139] like Figure 11 As shown, a schematic structural diagram of a quartz glass having a biomimetic nanostructure layer 2 in the shape of NJUPT in this embodiment includes a quartz glass substrate and a biomimetic nanostructure layer 2 on the substrate, which includes anisotropic flaky nanostructures 3 in the shape of NJ and isotropic columnar nanostructures 4 in the shape of UPT. The quartz glass substrate has an area of 2 cm*2 cm and a thickness of 0.5 mm. The thickness of the anisotropic flaky nanostructures 3 is 190-210 nm, and the thickness of the isotropic columnar nanostructures 4 is 280-320 nm. The material is polyimide.

[0140] The isotropic columnar nanostructure 4 of this embodiment is prepared by the following process: Figure 2 :

[0141] A PI film was spin-coated and cured on a glass substrate to a thickness of approximately 20 µm. The specific operation and experimental parameters are as follows:

[0142] 1. Fix the glass substrate on the vacuum suction cup of the glue roller and apply an appropriate amount of 5000cp viscosity PI solution in the middle;

[0143] 2. Spin coating parameters are 400r / min*10s (acceleration 300) + 1000r / min*30s (acceleration 800);

[0144] 3. Leveling: Let the film stand for 60~90s;

[0145] 4. Soft baking: Place the sheet on a hot plate and heat at 120°C for 3 minutes;

[0146] 5. PI curing: Use gradient temperature to heat and cure PI, with the temperature and time set as 140℃*30 minutes + 200℃*30 minutes + 300℃*90 minutes;

[0147] An opaque aluminum alloy mask plate with a hollow NJUPT logo was attached to the side of the glass substrate where the PI film was not attached. First, the UPT pattern was covered with another mask plate, and the NJ pattern area was scanned unidirectionally using a UV laser. Then, the NJ pattern was covered with a mask plate, and the UPT pattern area was scanned bidirectionally using a UV laser. The specific operation and experimental parameters are as follows: the UV laser was aligned with the side of the glass substrate where the PI film was not attached, and the control area was the NJ pattern. The laser process parameters were: laser energy density 89mj / cm 2 The laser scanning frequency was 340 times, and the laser scanning direction was unidirectional (along the X-axis). Nanoscale cavitation occurred at the interface of the PI film in the laser scanning area, and the interface reached a sub-peeling state. At this time, nanofiber connection was generated at the interface of the PI film and the glass substrate. The laser irradiation position was adjusted, and the UV laser was used to scan the area with the UPT pattern. The laser process parameters were controlled as follows: laser energy density was 89 mj / cm 2 The laser scans 62 times along the X-axis and Y-axis in a bidirectional (X-axis and Y-axis) direction, causing nanoscale cavitation at the PI interface in the laser scanning area, bringing the interface to a sub-peeling state. At this point, nanofibers form at the interface between the PI film and the glass substrate. A cut is made along the edge of the NJUPT letter, and a heat release tape is evenly applied to the PI film area with the NJUPT pattern. The heat release tape here acts as an external force to assist in peeling the PI film from the glass substrate.

[0148] The heat release tape is heated at 110° C. to complete the heat release process of the PI film, thereby preparing the quartz glass and PI film with the bionic nanostructure layer 2.

[0149] Example 8

[0150] This example tests the effect of scanning direction on nanopillar clusters. Figure 12 As shown in the figure, when exploring the effect of laser scanning direction, a PI sample was divided into four areas. The laser scanning direction of area I was vertically upward, the scanning direction of area II was 45° upward, the laser scanning direction of area II was horizontally rightward and vertically upward, and the number of laser irradiation in each direction was half of the total number of irradiation. The scanning direction of area IV was horizontally rightward. All areas were scanned using the same laser parameters, with a laser energy density of 105 mJ / cm 2 , the number of laser irradiations is 40 times.

[0151] The surface of the peeled PI film was observed under an electron microscope, as shown in Figure 12 As shown in (a), four different scanning directions are divided into an area of about 2×2 mm. Figure 12 (a) The regions and Figure 12 The areas in the scanning direction marked in (b) correspond to each other. Figure 12 (c) is a detailed image of each region under a high magnification electron microscope. The surface morphology of the four regions appears to be randomly distributed nanopillar structures at the same density. Many nanopillars are clustered to form long strips, and these clusters appear to have directionality. The figure uses dotted boxes to mark some nanopillar clusters. Most of the nanopillar clusters in region I are horizontally adhered together, the cluster direction in region II is oblique, the clusters in region III are often shorter and the cluster direction is very random, and the cluster direction in region IV is mostly vertical. It was found that when the laser is scanned unidirectionally, the cluster direction of the nanopillars is perpendicular to the laser scanning direction. When the laser is cross-scanned, the nanopillars do not have a fixed cluster direction, the clusters are shorter, and the nanopillars tend to be independently distributed.

[0152] The biomimetic nanostructure layer of this embodiment achieves nanometer-scale optical resolution. This unique nanoscale optical resolution capability stems from the biomimetic reconstruction of biological micro- and nanostructures. The randomness of the structure can be used to construct physically unclonable anti-counterfeiting functional units, demonstrating significant technical advantages in areas such as micro- and nanoscale anti-counterfeiting identification and high-security information encryption. This innovative research provides an important theoretical basis and technical path for the development of a new generation of intelligent anti-counterfeiting materials.

[0153] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A physical unclonable anti-counterfeiting structure based on biomimetic nanostructures, characterized by: The invention comprises a substrate (1); a biomimetic nanostructure layer (2) is provided on the substrate (1); the biomimetic nanostructure layer (2) comprises anisotropic flaky nanostructures (3) and isotropic columnar nanostructures (4); the isotropic columnar nanostructures (4) are prepared by bidirectional scanning along the X-axis and Y-axis of the surface of the substrate (1) by ultraviolet laser, and the column spacing of the flaky structures in the anisotropic flaky nanostructures (3) is 100-240nm and the height is 120-260nm; the isotropic columnar nanostructures (4) are prepared by bidirectional scanning along the X-axis and Y-axis of the surface of the substrate (1) by ultraviolet laser. The anisotropic flaky nanostructure (3) is formed by peeling off after unidirectional scanning along the X-axis of the surface of the substrate (1) with an ultraviolet laser, and the columnar diameter of the isotropic columnar nanostructure (4) ranges from 40 to 45 nm, the height ranges from 160 to 320 nm, and the period ranges from 70 to 130 nm; the anisotropic flaky nanostructure (3) and the isotropic columnar nanostructure (4) are arranged in the same plane in a random multimodal manner; the random multimodal manner includes one or both of an adjustment arrangement manner and a proportional relationship manner.

2. The physical unclonable anti-counterfeiting structure based on biomimetic nanostructure according to claim 1, characterized in that: The thickness of the bionic nanostructure layer (2) is 120nm-320nm.

3. The physical unclonable anti-counterfeiting structure based on biomimetic nanostructure according to claim 1, characterized in that: The substrate (1) is a flexible PI film or a rigid quartz glass, and the substrate (1) using a flexible PI film is compatible with a rigid substrate or a flexible substrate.

4. The physical unclonable anti-counterfeiting structure based on biomimetic nanostructure according to claim 1, characterized in that: The material used for the bionic nanostructure layer (2) is polyimide.

5. The physical unclonable anti-counterfeiting structure based on biomimetic nanostructure according to claim 3, characterized in that: The rigid substrate is one of a quartz glass substrate and a silicon wafer, and the flexible substrate is one of PI, PDMS, and PVA.

6. The use of the physical unclonable anti-counterfeiting structure based on biomimetic nanostructure according to any one of claims 1 to 5, characterized in that: The anti-counterfeiting structure is applied to the anti-counterfeiting of articles, and the physical non-clonable anti-counterfeiting structure on the substrate (1) is affixed to the surface of an article as an anti-counterfeiting label.

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