A fast-response surface multi-level wrinkle, its preparation method and application

Abstract

The application discloses a kind of fast response surface multistage corrugation and its preparation method and application.The preparation method includes the following steps: (1) acrylic polyurethane, octadecyl acrylate is added to reaction vessel, then crosslinking agent, photo-initiator are added to obtain transparent solution, which is poured into the surface of polytetrafluoroethylene film, and is cured under ultraviolet lamp to obtain shape memory material SMP;(2) polydimethylsiloxane is stirred uniformly with curing agent, coated on the upper surface of SMP and cured to obtain SMP-PDMS, which is modified using dopamine to obtain dopamine modified SMP-PDMS;(3) by gas-liquid self-organization method, microspheres are self-assembled on water surface, dopamine modified SMP-PDMS is stretched into water, and is naturally air-dried after being fished up to obtain Ms-SMP-PDMS;(4) Ms-SMP-PDMS is heated, stretched deformation is fixed, and the deformation is released to original length after cooling to obtain surface multistage corrugation.The application combines two-dimensional photonic crystal structure with shape memory material corrugation structure, designs multistage corrugation, and realizes optical encryption.

Description

Technical Field

[0001] This invention relates to the field of smart responsive wrinkle materials technology, and in particular to a fast-response surface multi-level wrinkle, its preparation method, and its application. Background Technology

[0002] Optical information encryption technology involves functional material encryption methods, including metallic plasmon resonance encoding, photonic crystal structural color materials, surface micropattern structural color materials, and organic-nanomaterials with fluorescent anti-counterfeiting encryption functions. Traditional surface micropatterning technology is mainly achieved through laser etching (ZL202110524891.0), electrochemical etching (ZL201410269475.0), photolithography (ZL202010811304.1), flatbed printing, and imprinting. These methods are mature, stable, and reproducible, and have been industrialized, but the manufacturing equipment is expensive and the operation process is complex. Developing a method that does not rely on traditional etching technology and can dynamically control the shape, size, and surface properties of patterns has become an international hot topic. Early methods mainly utilized boundary effects to control the wrinkle morphology of metal / PDMS systems. The Whitesides team first deposited metal thin films on PDMS substrates with relief structures and induced wrinkling through heating / cooling. Subsequently, researchers attempted to prepare multi-level wrinkles using mechanical stretching release, plasma / UV irradiation, heat treatment, sol-gel drying, and solvent diffusion methods. The surface wrinkle micropatterns and anti-counterfeiting information do not have strict limitations on the choice of film / substrate materials; polydimethylsiloxane elastomer is typically used as the substrate material, and the elastic modulus is controlled by adjusting the ratio of prepolymer and crosslinking agent, curing temperature, and reaction time. Wrinkles can be achieved on both conventional rigid films and soft substrates by adjusting the elastic modulus, coefficient of thermal expansion, and solvent swelling capacity. Research methods mainly focus on film / substrate interface compatibility, material and process selection for rigid films, differences in elastic modulus and coefficient of thermal expansion between film and substrate, substrate selectivity, and control of wrinkle size and morphology. While one-dimensional ordering of wrinkles can be achieved, precise control of wrinkle orientation and position in two dimensions is difficult. Summary of the Invention

[0003] The purpose of this invention is to provide a fast-response surface multi-level wrinkle, its preparation method, and its application. Based on the construction of optical structural color thin films with two-dimensional micro-nano morphology, this invention studies the preparation of intelligent responsive optical composite materials and the interface structure control method. It achieves control over the size and morphological stability of wrinkles through thermal stimulation response, aiming to achieve optical encryption through intelligent control of wrinkle initiation / reduction. It has great prospects in smart windows, optically rewritable displays, and optical anti-counterfeiting.

[0004] This invention is achieved through the following technical solutions:

[0005] A method for preparing fast-response surface multi-level wrinkles includes the following steps:

[0006] (1) Add acrylic polyurethane and octadecyl acrylate in a mass ratio of 2:8-8:2 to a reaction vessel, then add crosslinking agent and photoinitiator in sequence, stir evenly at 50℃-70℃ to obtain a light yellow transparent solution, pour the transparent solution onto the surface of polytetrafluoroethylene film, and then cover both the solution surface and the lower surface of polytetrafluoroethylene film with a glass plate, and solidify it to obtain shape memory material SMP attached to the glass plate. Avoid air bubbles during the covering process and fix it with clips;

[0007] (2) Mix polydimethylsiloxane (Dow Corning DC184PDMS) and curing agent at a mass ratio of 9-11:1, stir evenly, take a certain amount and coat it on the surface of the shape memory material SMP, leave it overnight and cure naturally to obtain SMP-PDMS, immerse SMP-PDMS in a hydrochloric acid dopamine solution containing Tris-hydrochloric acid buffer, wash it after immersion, and obtain dopamine modified SMP-PDMS;

[0008] (3) Fill a container with water to 3 / 5-4 / 5 of its volume, fix a clean glass slide at an angle, and slowly drop the photonic crystal microsphere solution onto the surface of the glass slide. Under the action of gravity, the microsphere solution will self-assemble on the water surface through the gas-liquid self-organization method. Slowly insert the dopamine-modified SMP-PDMS into the water, then lift the photonic crystal upwards. Allow the material to air dry naturally to obtain Ms-SMP-PDMS.

[0009] (4) Heat Ms-SMP-PDMS below 45°C until the surface shows the color of photonic crystal structure, stretch it to 5%-100% of the original length, then fix the deformation and cool to room temperature, continue to heat to 45°C, and the sample releases the deformation to the original length to obtain a fast-response multi-level wrinkle on the surface.

[0010] SMP-PDMS was immersed in a dopamine hydrochloride solution containing Tris-hydrochloric acid buffer for 20-28 hours to allow a thin, light gray layer of dopamine to adhere to the surface of the SMP. The surface-deposited dopamine was gently rinsed with water and the solution was then ready for use to obtain dopamine-modified SMP-PDMS.

[0011] Preferably, the mass ratio of acrylic polyurethane and octadecyl acrylate in step (1) is 4:6-6:4. The curing conditions are as follows: place it in a UV curing apparatus and cure simultaneously for 10 minutes at UV wavelengths of 254nm and 365nm.

[0012] Preferably, the crosslinking agent in step (1) is selected from one or more of trimethylolpropane triacrylate, dipropylene glycol diacrylate and diethylene glycol diacrylate, and the crosslinking agent accounts for 0.5%-4% of the total mass of acrylic polyurethane and octadecyl acrylate.

[0013] Preferably, the photoinitiator in step (1) is selected from one or more of benzophenone, 2,2-dimethoxy-2-phenylacetophenone and phenylethylenedione, and the photoinitiator accounts for 0.5%-4% of the total mass of acrylic polyurethane and octadecyl acrylate.

[0014] Preferably, the dopamine hydrochloride solution containing Tris-hydrochloric acid buffer in step (2) is prepared by the following steps: dissolving dopamine hydrochloride in hydrochloric acid buffer at pH=8.5, and after the dopamine solid dissolves, a dopamine hydrochloride solution containing Tris-hydrochloric acid buffer is obtained, wherein the mass-volume ratio of dopamine hydrochloride to hydrochloric acid buffer is 0.05-6 g / mL.

[0015] Preferably, in the SMP-PDMS described in step (2), the thickness of the SMP is 0.02-0.5 mm and the thickness of the PDMS is 0.1-1 mm.

[0016] Preferably, the photonic crystal microsphere solution in step (3) is prepared by the following steps: mixing an aqueous solution of photonic crystal microspheres with n-propanol, wherein the volume ratio of the aqueous solution of photonic crystal microspheres to n-propanol is 1:4-4:1. The aqueous solution of photonic crystal microspheres and n-propanol are mixed, shaken evenly, and placed in an ultrasonic cleaner for 12 hours to disperse the microspheres evenly in the solvent n-propanol. Ice is added during the process to avoid the water temperature of the ultrasonic cleaner being too high, which would affect the dispersion effect of the microspheres.

[0017] Further preferred, in step (3), water is filled into the container to about 2 / 3 of its volume, and the clean glass plate is fixed at 45°.

[0018] Further preferably, the solid content of the photonic crystal microsphere aqueous solution in step (3) is 1%-10%, and the photonic crystal microspheres are silica microspheres or polystyrene microspheres. The size of the photonic crystal microspheres is 0.1-10 μm.

[0019] The fast-response surface multi-level wrinkles obtained by the above preparation method in this invention endow the surface shape memory material with ordered multi-level wrinkles.

[0020] This invention also protects the application of the aforementioned fast-response surface multi-level wrinkles in anti-counterfeiting and intelligent identification. The fast-response surface multi-level wrinkles are heated, and a pattern stamp is used to imprint the wrinkles. The surface is then slowly cooled to room temperature, and the pattern stamp is removed, resulting in a stamp pattern with photonic crystal structural colors. Further heating causes the pattern to disappear, achieving optical encryption. This invention, based on the thermal response of shape memory materials and combined with the structural colors of two-dimensional photonic crystals, achieves optical encryption through the intelligent control of wrinkle initiation / removal by preparing intelligent optically responsive composite materials and regulating the interface multi-level wrinkle structure. It shows great promise in areas such as smart windows, optically rewritable displays, and optical anti-counterfeiting.

[0021] Compared with the prior art, the beneficial effects of the present invention are:

[0022] (1) The present invention prepares two-dimensional surface wrinkles by uniaxially stretching a double-layer film of surface shape memory material / PDMS elastomer substrate and by adjusting the thickness of shape memory material and PDMS.

[0023] (2) Shape memory materials are controlled by thermal stimulation to achieve wrinkling / wrinkle removal through the crystallization melting temperature. Below the crystallization melting temperature, the reversible polymer chains are frozen, and the material is also in a frozen state. When the temperature rises to the crystallization melting temperature, the reversible polymer chain segments begin to move. When an external force is applied to the material, the material deforms. If this shape is maintained and cooled at the crystallization melting temperature, the polymer chains freeze, and the shape obtained by the material under the external force will be preserved. When the temperature rises above the crystallization melting temperature again, the polymer chains move again, the molecular chain segment orientation gradually disappears, and the material regains high elasticity. If no external force is applied to the material at this time, the material will return to its initial shape. This process is simple.

[0024] (3) This invention combines a two-dimensional photonic crystal structure with a shape memory material wrinkle structure to design multi-level wrinkles and achieve optical encryption. Attached Figure Description

[0025] Figure 1 The diagram shows the simplified steps of the fast-response surface multi-level wrinkle and its optical encryption preparation in Examples 1-4.

[0026] Figure 2 This is a microscopic image of the photonic crystal on the surface of the sample in Example 1 under an electron microscope.

[0027] Figure 3 This is a microscopic image of the multi-level wrinkles on the surface of Example 1 under a polarizing microscope.

[0028] Figure 4 The image shows the appearance of the stamp pattern with photonic crystal structure color in Example 2.

[0029] Figure 5 This is an image showing the appearance of the disappearance of the stamp pattern of the photonic crystal structure color in Example 2.

[0030] Figure 6 The image shows the apparent morphology of Ms-SMP-PDMS sample from Example 3 at room temperature.

[0031] Figure 7 The image shows the apparent morphology of Ms-SMP-PDMS sample from Example 3 after heating.

[0032] Figure 8 The image shows the appearance of the sample from Example 4 after it was stretched to 90% deformation and then fixed and cooled to room temperature.

[0033] Figure 9 The image shows the electron microscopy morphology of the self-organized photonic crystal on the surface of SMP-PDMS without dopamine modification, as shown in Comparative Example 1.

[0034] Figure 10 The image shows the microscopic morphology of the multi-level wrinkles on the surface of the sample in Comparative Example 2 under a polarizing microscope.

[0035] Figure 11 The image shows the microscopic morphology of the multi-level wrinkles on the surface of the sample in Comparative Example 3 under a polarizing microscope. Detailed Implementation

[0036] The present invention will be further described in detail below with reference to the embodiments. These embodiments are for illustrative purposes only and are not intended to limit the scope of the invention. Experimental methods in the following embodiments that do not specify specific conditions are generally performed under conventional conditions in the art or as recommended by the manufacturer; the raw materials and reagents used, unless otherwise specified, are considered to be commercially available through conventional markets. In the following embodiments, the curing agent is Corning DC184PDMS. The amounts of each component are expressed in parts by mass (g, mL).

[0037] Example 1

[0038] Reference Figure 1 A method for preparing fast-response surface multi-level wrinkles includes the following steps:

[0039] (1) Add acrylic polyurethane and octadecyl acrylate total monomers in a mass ratio of 3:7 to a 20mL small glass bottle, then add 4% of the total monomer mass of crosslinking agent trimethylolpropane triacrylate and 2% of the total monomer mass of photoinitiator benzophenone. Stir magnetically at 60℃ until homogeneous to obtain a light yellow transparent solution.

[0040] A certain amount of the prepared solution was poured onto the surface of a polytetrafluoroethylene (PTFE) film. Then, a glass plate was placed on both the surface of the solution and the underside of the PTFE film, avoiding any bubbling residue during the process. The plate was then fixed with clips and placed in a UV curing apparatus. The plate was simultaneously cured for 10 minutes at UV wavelengths of 254 nm and 365 nm to obtain a shape memory material (SMP) attached to the glass plate. The thickness of the SMP was 40 μm.

[0041] (2) Dow Corning DC184PDMS (polydimethylsiloxane) and Corning DC184PDMS curing agent were mixed at a mass ratio of 10:1 and stirred manually. A certain amount was coated on the surface of the above shape memory material and left to cure naturally overnight to obtain SMP-PDMS, wherein the thickness of PDMS was 0.1 mm. Take a clean 150 mL plastic beaker, add 5 g of dopamine hydrochloride, and then add 20 mL of hydrochloric acid buffer (pH = 8.5). After the dopamine solid dissolves, put SMP-PDMS into the beaker and soak for 24 h to make a thin layer of light gray dopamine adhere to the surface of SMP. Gently rinse the surface of the deposited dopamine with water and wash it clean for later use to obtain dopamine modified SMP-PDMS.

[0042] (3) A photonic crystal microsphere solution with a solid content of 4% silica photonic crystal microsphere aqueous solution was obtained by mixing with n-propanol. The microsphere size was 1 μm. The volume ratio of microsphere aqueous solution to n-propanol was 1:4. The solution was shaken evenly and placed in an ultrasonic cleaner for 12 hours to disperse the microspheres evenly in the solvent. Ice was added during the process to avoid the ultrasonic cleaner water temperature being too high, which would affect the microsphere dispersion effect. The photonic crystal microsphere solution was obtained.

[0043] (4) Fill a 12cm diameter petri dish with about 2 / 3 water. Fix a clean glass slide at 45°. Manually and slowly drop the photonic crystal microsphere solution onto the glass slide surface. Under the influence of gravity, the microsphere solution undergoes gas-liquid self-assembly, allowing the microspheres to self-assemble on the water surface. Use tweezers to slowly submerge the dopamine-modified SMP-PDMS in the water, then lift the photonic crystal out. Allow the material to air dry naturally to obtain Ms-SMP-PDMS. Measure the morphology of the Ms-SMP-PDMS photonic crystal using an electron microscope, as shown below. Figure 2 As shown, electron microscopy reveals that the microspheres are hexagonally close-packed and adhere to the substrate surface through a dopamine interlayer, with filamentous dopamine connectives visible between the microspheres.

[0044] (5) Ms-SMP-PDMS was heated at 45℃, and the sample surface exhibited a photonic crystal structure color. After stretching by 10% deformation, the deformation was fixed and cooled to room temperature. Heating was then repeated to 45℃, and the sample released its deformation to its original length, resulting in a fast-responding multi-level surface wrinkle, such as... Figure 3As shown, when observed with a polarizing microscope, the sample surface exhibits a regular multi-level wrinkled morphology due to the presence of a photonic crystal structure.

[0045] (6) Then heat the multi-level wrinkles on the surface obtained in step (5) to 45°C, use a pattern stamp to imprint the multi-level wrinkles on the surface, slowly cool down to room temperature, remove the pattern stamp, and obtain a stamp pattern with photonic crystal structure color. Continue heating to 45°C, the pattern disappears, and the optical encryption of the pattern is achieved.

[0046] Example 2

[0047] Reference Figure 1 A method for preparing fast-response surface multi-level wrinkles includes the following steps:

[0048] (1) Acrylic polyurethane and octadecyl acrylate monomers were added to a 20mL glass bottle at a mass ratio of 4:6. Then, 1% of the total monomer mass of trimethylolpropane triacrylate crosslinking agent, 1% of the total monomer mass of tripropylene glycol diacrylate crosslinking agent, and 4% of the total monomer mass of benzophenone photoinitiator were added sequentially. The mixture was magnetically stirred at 60℃ to obtain a pale yellow transparent solution. A certain amount of the prepared solution was poured onto the surface of a polytetrafluoroethylene (PTFE) film. A glass slide was then placed on both the solution surface and the underside of the PTFE film, avoiding air bubbles. The slide was fixed with clips and placed in a UV curing machine for 10 minutes. The UV wavelengths were 254nm and 365nm, resulting in a shape memory material (SMP) attached to the glass slide with a thickness of 80μm.

[0049] (2) Mix Dow Corning DC184PDMS (polydimethylsiloxane) and Corning DC184PDMS curing agent at a mass ratio of 10:1, stir manually, take a certain amount and coat it on the surface of the above shape memory material, leave it overnight and let it cure naturally to obtain SMP-PDMS, wherein the thickness of PDMS is 0.4mm.

[0050] Take a clean 150mL plastic beaker, add 20g of dopamine hydrochloride, and then add 60mL of hydrochloric acid buffer (pH=8.5). After the dopamine solid dissolves, put SMP-PDMS into the beaker and soak for 24h to allow a thin, light gray layer of dopamine to adhere to the surface of the SMP. Gently rinse the surface with water to remove the dopamine deposit, and then wash it clean for later use to obtain dopamine-modified SMP-PDMS.

[0051] (3) A photonic crystal microsphere solution with a solid content of 2% was obtained by mixing polystyrene photonic crystal microsphere aqueous solution with n-propanol. The microsphere size was 2μm. The volume ratio of microsphere aqueous solution to n-propanol was 1:4. The solution was shaken evenly and placed in an ultrasonic cleaner for 12h to disperse the microspheres evenly in the solvent. Ice was added during the process to avoid the ultrasonic cleaner water temperature being too high, which would affect the microsphere dispersion effect.

[0052] (4) Fill a 12cm diameter petri dish with about 2 / 3 water. Fix a clean glass slide at 45°. Manually and slowly drop the photonic crystal microsphere solution onto the surface of the glass slide. Under the action of gravity, the microsphere solution self-assembles on the water surface through a gas-liquid self-organization method. Use tweezers to slowly submerge the dopamine-modified SMP-PDMS in the water, then lift the photonic crystal out. Allow the material to air dry naturally to obtain Ms-SMP-PDMS.

[0053] (5) Ms-SMP-PDMS is heated at 45°C. The sample surface exhibits photonic crystal structure color. It is stretched to 40% deformation, then the deformation is fixed and cooled to room temperature. It is then heated to 45°C again, and the sample releases the deformation to its original length, resulting in a fast-response multi-level surface wrinkle.

[0054] (6) Heat to 45℃, use a pattern stamp to imprint the multi-level wrinkles on the surface, slowly cool to room temperature, remove the pattern stamp, and obtain a stamp pattern with photonic crystal structure colors, such as Figure 4 As shown, the sample surface exhibits a green spherical pattern. Upon further heating to 45°C, the spherical pattern disappears. Figure 5 As shown, optical encryption of the pattern is achieved.

[0055] Example 3

[0056] Reference Figure 1 A method for preparing fast-response surface multi-level wrinkles includes the following steps:

[0057] (1) Acrylic polyurethane and octadecyl acrylate monomers were added to a 20mL glass bottle at a mass ratio of 8:2. Then, 0.5% of the total monomer mass of diethylene glycol diacrylate crosslinking agent, 1% of the total monomer mass of benzophenone photoinitiator, and 0.5% of the total monomer mass of photoinitiator diphenyl glycol ketone were added sequentially. The mixture was magnetically stirred at 60℃ to obtain a pale yellow transparent solution. A certain amount of the prepared solution was poured onto the surface of a polytetrafluoroethylene film. A glass plate was then placed on both the surface of the solution and the underside of the polytetrafluoroethylene film, avoiding any bubbling residue. The plate was fixed with clips and placed in a UV curing machine to cure for 10 minutes at UV wavelengths of 254nm and 365nm, resulting in a shape memory material (SMP) attached to the glass plate with a thickness of 200μm.

[0058] (2) Dow Corning DC184PDMS (polydimethylsiloxane) and Corning DC184PDMS curing agent were mixed at a mass ratio of 10:1 and stirred manually. A certain amount was coated on the surface of the above shape memory material and left to cure naturally overnight to obtain SMP-PDMS, wherein the thickness of PDMS was 0.6 mm. Take a clean 150 mL plastic beaker, add 50 g of dopamine hydrochloride, and then add 100 mL of hydrochloric acid buffer (pH = 8.5). After the dopamine solid dissolves, put SMP-PDMS into the beaker and soak for 24 h to make a thin layer of light gray dopamine adhere to the surface of SMP. Gently rinse the surface of the deposited dopamine with water and wash it clean for later use to obtain dopamine modified SMP-PDMS.

[0059] (3) A photonic crystal microsphere solution with a solid content of 8% was obtained by mixing polystyrene photonic crystal microsphere aqueous solution with n-propanol. The microsphere size was 200 nm. The volume ratio of microsphere aqueous solution to n-propanol was 2:1. The solution was shaken evenly and placed in an ultrasonic cleaner for 12 hours to disperse the microspheres evenly in the solvent. Ice was added during the process to avoid the ultrasonic cleaner water temperature being too high, which would affect the microsphere dispersion effect.

[0060] (4) Fill a 12cm diameter petri dish with about 2 / 3 water. Fix a clean glass slide at 45°. Manually and slowly drop the photonic crystal microsphere solution onto the glass slide surface. Under the influence of gravity, the microsphere solution undergoes gas-liquid self-assembly, allowing the microspheres to self-assemble on the water surface. Use tweezers to slowly submerge the dopamine-modified SMP-PDMS in the water, then lift the photonic crystal out. Allow the material to air dry naturally to obtain Ms-SMP-PDMS. Figure 6 As shown.

[0061] (5) When Ms-SMP-PDMS is heated at 45℃, the sample surface exhibits photonic crystal structure colors, such as... Figure 7 As shown, the sample is stretched to 60% deformation, then fixed and cooled to room temperature, and then heated to 45°C. The sample is then released to its original length, resulting in a fast-responding multi-level wrinkle on the surface.

[0062] (6) Heat to 45°C, use a pattern stamp to imprint the multi-level wrinkles on the surface, slowly cool down to room temperature, remove the pattern stamp, and obtain a stamp pattern with photonic crystal structure color. Continue heating to 45°C, the pattern disappears, and the optical encryption of the pattern is achieved.

[0063] Example 4

[0064] Reference Figure 1 A method for preparing fast-response surface multi-level wrinkles includes the following steps:

[0065] (1) Acrylic polyurethane and octadecyl acrylate monomers were added to a 20mL glass bottle at a mass ratio of 6:4. Then, 2% of the total monomer mass of trimethylolpropane triacrylate crosslinking agent, 0.5% of the total monomer mass of dipropylene glycol diacrylate crosslinking agent, and 3% of the total monomer mass of photoinitiator benzophenone were added sequentially. The mixture was magnetically stirred at 60℃ to obtain a pale yellow transparent solution. A certain amount of the prepared solution was poured onto the surface of a polytetrafluoroethylene film. A glass slide was then placed on both the surface of the solution and the underside of the polytetrafluoroethylene film, avoiding any bubbling residue. The slide was fixed with clips and placed in a UV curing machine to cure for 10 minutes at UV wavelengths of 254nm and 365nm, resulting in a shape memory material (SMP) attached to the glass slide with a thickness of 500μm.

[0066] (2) Dow Corning DC184PDMS (polydimethylsiloxane) and Corning DC184PDMS curing agent were mixed at a mass ratio of 10:1 and stirred manually. A certain amount was coated on the surface of the above shape memory material and left to cure naturally overnight to obtain SMP-PDMS, wherein the thickness of PDMS was 1 mm. Take a clean 150 mL plastic beaker, add 30 g of dopamine hydrochloride, and then add 100 mL of hydrochloric acid buffer (pH = 8.5). After the dopamine solid dissolves, put SMP-PDMS into the beaker and soak for 24 h to make a thin layer of light gray dopamine adhere to the surface of SMP. Gently rinse the surface of the deposited dopamine with water and wash it clean for later use to obtain dopamine modified SMP-PDMS.

[0067] (3) A photonic crystal microsphere solution with a solid content of 6% silica photonic crystal microsphere aqueous solution was mixed with n-propanol to obtain a photonic crystal microsphere solution with a microsphere size of 500 nm. The volume ratio of microsphere aqueous solution to n-propanol was 1:2. The solution was shaken evenly and placed in an ultrasonic cleaner for 12 hours to disperse the microspheres evenly in the solvent. Ice was added during the process to avoid the ultrasonic cleaner water temperature being too high, which would affect the microsphere dispersion effect.

[0068] (4) Fill a 12cm diameter petri dish with about 2 / 3 water. Fix a clean glass slide at 45°. Manually and slowly drop the photonic crystal microsphere solution onto the surface of the glass slide. Under the action of gravity, the microsphere solution self-assembles on the water surface through a gas-liquid self-organization method. Use tweezers to slowly submerge the dopamine-modified SMP-PDMS in the water, then lift the photonic crystal out. Allow the material to air dry naturally to obtain Ms-SMP-PDMS.

[0069] (5) Ms-SMP-PDMS was heated at 45℃, and the sample surface exhibited a photonic crystal structure color. It was then stretched to 90% deformation, and the deformation was fixed and cooled to room temperature. Figure 8As shown. Further heating to 45°C caused the sample to release its deformation back to its original length, resulting in a rapidly responding multi-level surface wrinkle.

[0070] (6) Heat to 45°C, use a pattern stamp to imprint the multi-level wrinkles on the surface, slowly cool down to room temperature, remove the pattern stamp, and obtain a stamp pattern with photonic crystal structure color. Continue heating to 45°C, the pattern disappears, and the optical encryption of the pattern is achieved.

[0071] Comparative Example 1

[0072] A method for preparing surface wrinkles includes the following steps:

[0073] (1) Acrylic polyurethane and octadecyl acrylate monomers were added to a 20mL glass bottle at a mass ratio of 3:7. Then, 4% of the total monomer mass of the crosslinking agent trimethylolpropane triacrylate and 2% of the total monomer mass of the photoinitiator benzophenone were added sequentially. The mixture was magnetically stirred at 60℃ to obtain a pale yellow transparent solution. A certain amount of the prepared solution was poured onto the surface of a polytetrafluoroethylene film. A glass plate was then placed on both the surface of the solution and the underside of the polytetrafluoroethylene film, avoiding any bubbling residue. The plate was fixed with clips and placed in a UV curing machine to cure for 10 minutes at UV wavelengths of 254nm and 365nm, resulting in a shape memory material (SMP) attached to the glass plate with a thickness of 40μm.

[0074] (2) Mix Dow Corning DC184PDMS (polydimethylsiloxane) and Corning DC184PDMS curing agent at a mass ratio of 10:1, stir manually, take a certain amount and coat it on the surface of the above shape memory material, leave it overnight and let it cure naturally to obtain SMP-PDMS, wherein the thickness of PDMS is 0.1mm.

[0075] (3) A photonic crystal microsphere solution with a solid content of 4% silica photonic crystal microsphere aqueous solution was mixed with n-propanol to obtain a photonic crystal microsphere solution with a microsphere size of 1μm. The volume ratio of microsphere aqueous solution to n-propanol was 1:4. The solution was shaken evenly and placed in an ultrasonic cleaner for 12 hours to disperse the microspheres evenly in the solvent. Ice was added during the process to avoid the ultrasonic cleaner water temperature being too high, which would affect the microsphere dispersion effect.

[0076] (4) Fill a 12cm diameter petri dish with about 2 / 3 water. Fix a clean glass slide at 45°. Manually and slowly drop the photonic crystal microsphere solution onto the glass slide surface. Under gravity, the microsphere solution undergoes gas-liquid self-assembly, allowing the microspheres to self-assemble on the water surface. Use tweezers to slowly submerge the SMP-PDMS in the water, then lift the photonic crystal out. Allow the material to air dry naturally. Observe the sample surface under an electron microscope. Since there is no dopamine-modified SMP-PDMS surface, the photonic crystal cannot adhere to the sample surface. Under the electron microscope, the sample surface is smooth. Figure 9 As shown.

[0077] Comparative Example 2

[0078] A method for preparing surface wrinkles includes the following steps:

[0079] (1) Acrylic polyurethane and octadecyl acrylate monomers were added to a 20mL glass bottle at a mass ratio of 3:7. Then, 4% of the total monomer mass of the crosslinking agent trimethylolpropane triacrylate and 2% of the total monomer mass of the photoinitiator benzophenone were added sequentially. The mixture was magnetically stirred at 60℃ to obtain a pale yellow transparent solution. A certain amount of the prepared solution was poured onto the surface of a polytetrafluoroethylene film. A glass plate was then placed on both the surface of the solution and the underside of the polytetrafluoroethylene film, avoiding any bubbling residue. The plate was fixed with clips and placed in a UV curing machine to cure for 10 minutes at UV wavelengths of 254nm and 365nm, resulting in a shape memory material (SMP) attached to the glass plate with a thickness of 40μm.

[0080] (2) Dow Corning DC184PDMS (polydimethylsiloxane) and Corning DC184PDMS curing agent were mixed at a mass ratio of 10:1 and stirred manually. A certain amount was coated on the surface of the above shape memory material and left to cure naturally overnight to obtain SMP-PDMS with a thickness of 0.1 mm. Take a clean 150 mL plastic beaker, add 5 g of dopamine hydrochloride, and then add 20 mL of hydrochloric acid buffer (pH = 8.5). After the dopamine solid dissolves, put SMP-PDMS into the tube and soak for 24 h to make a thin layer of light gray dopamine adhere to the surface of the SMP. Gently rinse the surface with water to remove the dopamine deposit, and wash it for later use to obtain dopamine modified SMP-PDMS.

[0081] (3) A photonic crystal microsphere solution with a solid content of 4% silica photonic crystal microsphere aqueous solution was mixed with n-propanol to obtain a photonic crystal microsphere solution with a microsphere size of 1μm. The volume ratio of microsphere aqueous solution to n-propanol was 1:4. The solution was shaken evenly and placed in an ultrasonic cleaner for 12 hours to disperse the microspheres evenly in the solvent. Ice was added during the process to avoid the ultrasonic cleaner water temperature being too high, which would affect the microsphere dispersion effect.

[0082] (4) Fill a 12cm diameter petri dish with about 2 / 3 water. Fix a clean glass slide at 45°. Manually and slowly drop the photonic crystal microsphere solution onto the surface of the glass slide. Under the action of gravity, the microsphere solution self-assembles on the water surface through a gas-liquid self-organization method. Use tweezers to slowly submerge the dopamine-modified SMP-PDMS in the water, then lift the photonic crystal out. Allow the material to air dry naturally to obtain Ms-SMP-PDMS.

[0083] (5) When Ms-SMP-PDMS is heated to 45℃, the sample surface exhibits a photonic crystal structure color. Stretching the sample by 10% under heating and then releasing the deformation to its original length does not produce a rapid-response multi-level surface wrinkle. Under an electron microscope, no wrinkle morphology is visible on the sample surface; the surface is smooth. Figure 10 As shown.

[0084] Comparative Example 3

[0085] A method for preparing surface wrinkles includes the following steps:

[0086] (1) Acrylic polyurethane and octadecyl acrylate monomers were added to a 20mL glass bottle at a mass ratio of 3:7. Then, 4% of the total monomer mass of the crosslinking agent trimethylolpropane triacrylate and 2% of the total monomer mass of the photoinitiator benzophenone were added sequentially. The mixture was magnetically stirred at 60℃ to obtain a pale yellow transparent solution. A certain amount of the prepared solution was poured onto the surface of a polytetrafluoroethylene film. A glass plate was then placed on both the surface of the solution and the underside of the polytetrafluoroethylene film, avoiding any bubbling residue. The plate was fixed with clips and placed in a UV curing machine to cure for 10 minutes at UV wavelengths of 254nm and 365nm, resulting in a shape memory material (SMP) attached to the glass plate with a thickness of 40μm.

[0087] (2) Dow Corning DC184PDMS (polydimethylsiloxane) and Corning DC184PDMS curing agent were mixed at a mass ratio of 10:1, stirred manually, and a certain amount was coated onto the surface of the above shape memory material. The mixture was left to cure naturally overnight to obtain SMP-PDMS, where the PDMS thickness was 0.1 mm. The SMP-PDMS was heated to 45°C, and the sample surface exhibited a photonic crystal structure color. After stretching by 10% deformation, the deformation was fixed and cooled to room temperature. Heating was then repeated to 45°C, and the sample released its deformation to its original length, resulting in a fast-response surface wrinkle. Because no photonic crystals were assembled on its surface, no multi-level wrinkles were observed, such as... Figure 11 As shown.

[0088] The above description of the embodiments is only for the purpose of helping to understand the technical solution and core idea of ​​the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made to the present invention without departing from the principle of the present invention, and these improvements and modifications also fall within the protection scope of the claims of the present invention.

Claims

1. A method for producing a fast responding surface multi-stage corrugation, characterized by, It comprises the following steps: (1) adding acrylic polyurethane and octadecyl acrylate with a mass ratio of 2:8-8:2 into a reaction container, then adding a crosslinking agent and a photoinitiator in sequence, stirring uniformly at 50-70℃ to obtain a light yellow transparent solution, pouring the transparent solution onto the surface of a polytetrafluoroethylene film, covering a piece of glass on the surface of the solution and the lower surface of the polytetrafluoroethylene film, curing to obtain a shape memory material SMP attached to the glass; (2) mixing polydimethylsiloxane and a curing agent with a mass ratio of 9-11:1, stirring uniformly, taking a certain amount of the mixture and coating on the upper surface of the shape memory material SMP, naturally curing overnight to obtain SMP-PDMS, wherein the thickness of the SMP is 0.02-0.5mm and the thickness of the PDMS is 0.1-1mm, immersing the SMP-PDMS into a dopamine hydrochloride solution containing a Tris-hydrochloric acid buffer, washing after the immersion is completed to obtain dopamine modified SMP-PDMS; (3) filling 3 / 5-4 / 5 of the volume of the container with water, fixing a clean glass piece obliquely, slowly dropping a photonic crystal microsphere solution on the surface of the glass piece, and realizing self-assembly of the microsphere solution on the water surface by a gas-liquid self-organizing method under the action of gravity, slowly extending the dopamine modified SMP-PDMS into the water, and then taking out the photonic crystal, and naturally air-drying the material to obtain Ms-SMP-PDMS, wherein the photonic crystal microsphere solution is prepared by mixing a photonic crystal microsphere aqueous solution with n-propanol, the volume ratio of the photonic crystal microsphere aqueous solution to n-propanol is 1:4-4:1, the solid content of the photonic crystal microsphere aqueous solution is 1%-10%, and the photonic crystal microspheres are silica microspheres or polystyrene microspheres; (4) heating the Ms-SMP-PDMS below 45℃, stretching to a deformation of 5%-100% of the original length after the surface presents a photonic crystal structural color, fixing the deformation, cooling to room temperature, and continuing to heat to 45℃ to release the deformation of the sample to the original length to obtain a surface multi-level wrinkle with rapid response.

2. The production method according to claim 1, characterized by, The mass ratio of the acrylic polyurethane to the octadecyl acrylate in step (1) is 4:6-6:

4.

3. The production method according to claim 1 or 2, characterized by, The crosslinking agent in step (1) is selected from one or more of trimethylolpropane triacrylate, tripropyleneglycol diacrylate and diethylene glycol diacrylate, and the mass fraction of the crosslinking agent in the total mass of the acrylic polyurethane and the octadecyl acrylate is 0.5%-4%.

4. The production method according to claim 1 or 2, characterized by, The photoinitiator in step (1) is selected from one or more of benzophenone, 2,2-dimethoxy-2-phenylacetophenone and benzil, and the mass fraction of the photoinitiator in the total mass of the acrylic polyurethane and the octadecyl acrylate is 0.5%-4%.

5. The preparation method according to claim 1, characterized in that, The Tris-hydrochloric acid buffer solution containing hydrochloric acid dopamine solution prepared by the following steps: hydrochloric acid dopamine is dissolved in hydrochloric acid buffer solution with pH=8.5, after the dopamine solid is dissolved, the Tris-hydrochloric acid buffer solution containing hydrochloric acid dopamine solution is obtained, and the mass-volume ratio of hydrochloric acid dopamine to hydrochloric acid buffer solution is 0.05-6 g / mL.

6. The method of any one of claims 1-5, wherein the method produces a fast responding surface multi-level wrinkle.

7. Use of the fast responding surface multistage corrugation of claim 6 in anti-counterfeit marking and intelligent identification, characterized in that, The fast responding surface multi-level wrinkle is heated, a pattern stamp is used to emboss the surface multi-level wrinkle, the temperature is slowly lowered to room temperature, the pattern stamp is removed, a stamp pattern with a photonic crystal structural color is obtained, heating is continued, the pattern disappears, and optical encryption of the pattern is achieved.

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