Preparation method of one-dimensional ordered flexible micro-nano controllable characteristic parameter wrinkle structure

Abstract

The application discloses a preparation method of a one-dimensional ordered flexible micro-nano controllable characteristic parameter wrinkle structure. After SU8 photoresist is diluted by cyclopentanone to obtain SU8 photoresist with different dilution ratios, the SU8 photoresist is spin-coated on a PDMS substrate by a three-section spin-coating method, and a one-dimensional ordered flexible micro-nano wrinkle structure is obtained after exposure and heating. The application adjusts the concentration of cyclopentanone, accurately controls the wrinkle parameters of the hard film-soft substrate double-layer structure, and achieves the micro-nano wrinkle structure with high parallelism, no crack, good order and high repeatability.

Description

Technical Field

[0001] This invention relates to a technology in the field of nanostructures, specifically a method for preparing one-dimensional ordered flexible micro / nano-scale wrinkled structures with controllable characteristic parameters. Background Technology

[0002] Ordered wrinkled structures on hard-film soft substrates are micro / nanostructures with high flexibility and plasticity. Due to their ability to bend and deform, they have various applications in fields such as tunable gratings, flexible displays, flexible electronics, and biomedicine. Currently, ordered wrinkled micro / nanostructures on hard-film soft substrates are mainly prepared using methods such as casting, pre-stretching, heating, and nanoimprinting. However, current fabrication methods still have some drawbacks. Casting methods have long production cycles, high production costs, limited precision, and are difficult to mass-produce. Pre-stretching and heating methods suffer from defects such as poor orderliness of the wrinkles and cracks in the micro / nanostructures. The disadvantages of nanoimprinting for manufacturing ordered wrinkled structures include high template costs, short template lifespan, limited material availability, and poor flexibility. Summary of the Invention

[0003] This invention addresses the shortcomings of existing methods, such as limited precision, difficulty in mass production, and poor orderliness. It proposes a method for preparing one-dimensional ordered flexible micro / nano-scale wrinkled structures with controllable characteristic parameters. By adjusting the concentration of cyclopentanone, the wrinkle parameters of the hard film-soft substrate bilayer structure can be precisely controlled, achieving micro / nano-scale wrinkled structures with high parallelism, no cracks, good orderliness, and high repeatability.

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

[0005] This invention relates to a method for preparing one-dimensional ordered flexible micro / nano-shaped wrinkled structures with controllable characteristic parameters. The method involves diluting SU8 with cyclopentanone to obtain SU8 photoresist with different dilution ratios, then spin-coating it onto a PDMS substrate using a three-stage spin-coating method, and finally obtaining a one-dimensional ordered flexible micro / nano-shaped wrinkled structure after exposure and heating.

[0006] The aforementioned one-dimensional order refers to a periodic wavy pattern.

[0007] The period is preferably a wavelength of 29.7 μm and an amplitude of 1.243 μm.

[0008] The different dilution ratios refer to: diluting SU8 photoresist with cyclopentanone, and mixing the cyclopentanone solution and SU8 photoresist at different volume ratios by shaking to form a homogeneous solution. Technical effect

[0009] This invention utilizes the properties of SU8 photoresist negative resist (after ultraviolet light irradiation, the exposed polymer crosslinks, thus increasing hardness) to prepare a high-perpendicularity, high-quality structure with alternating hard and soft phases, creating favorable boundary conditions. Stress is then applied through heating and cooling to fabricate a highly ordered wrinkled structure. This invention also utilizes cyclopentanone to dilute the SU8 photoresist, changing the SU8 concentration and consequently altering the wavelength and amplitude of the wrinkled structure, thus enabling the fabrication of a controllable wrinkle micro / nano structure with controllable wrinkle characteristic parameters. The method for fabricating one-dimensional ordered flexible micro / nano wrinkled structures using the SU8 photoresist hard film / soft substrate system provided by this invention effectively eliminates common defects in existing hard film / soft substrate wrinkled micro / nano structure fabrication, such as poor wrinkle order and cracks. Attached Figure Description

[0010] Figure 1 This is a flowchart of the present invention;

[0011] In the figure: 1 PDMS substrate, 2 PDMS substrate curing agent, 3 PDMS substrate after cutting, 4 plasma cleaner, 5 SU8 photoresist, 6 spin coating, 7 photomask, 8 UV light generated by UV exposure machine, 9 heating, 10 cooling to room temperature;

[0012] Figure 2 A three-dimensional laser scanning confocal microscope image of a wrinkled structure fabricated with undiluted SU8 photoresist, as shown in the example.

[0013] In the image: a is a three-dimensional image of the height of the one-dimensional ordered fold structure; b is a two-dimensional image of the height of the one-dimensional ordered fold pattern; c is... Figure 2 The height topology curve marked by the black line in b;

[0014] Figure 3 The volume ratio of cyclopentanone to SU8 photoresist in the example is 1:7, that is, a three-dimensional laser scanning confocal microscope image of the wrinkled structure made by SU8 photoresist diluted 1:7.

[0015] In the image: a is a 3D image of the height of a one-dimensional ordered fold pattern; b is a 2D image of the height of a one-dimensional ordered fold structure; c is... Figure 3 The height topology curve marked by the black line in b.

[0016] Figure 4 The volume ratio of cyclopentanone to SU8 photoresist in the example is 1:4, that is, the three-dimensional laser scanning confocal microscope image of the wrinkled structure made by SU8 photoresist diluted 1:4.

[0017] In the image: a is a three-dimensional image of the height of the one-dimensional ordered fold structure; b is a two-dimensional image of the height of the one-dimensional ordered fold pattern; c is... Figure 4 The height topology curve marked by the black line in b.

[0018] Figure 5 The volume ratio of cyclopentanone to SU8 photoresist in the example is 1:1, that is, the three-dimensional laser scanning confocal microscope image of the wrinkled structure made by the SU8 photoresist diluted 1:1.

[0019] In the image: a is a 3D image of the height of a one-dimensional ordered fold pattern; b is a 2D image of the height of a one-dimensional ordered fold structure; c is... Figure 5 The height topology curve marked by the black line in section a. Detailed Implementation

[0020] like Figure 1 As shown, this embodiment illustrates a method for fabricating a one-dimensional ordered flexible micro / nano-scale wrinkled structure with controllable characteristic parameters, comprising:

[0021] Step 1) Mix the PDMS substrate and curing agent at a mass ratio of 10:1 to prepare the PDMS substrate, and cut the PDMS substrate into 8×8mm pieces;

[0022] Step 2) Clean the PDMS substrate with a plasma cleaner for 20 seconds to change the wettability of PDMS, so that SU8 can be spin-coated onto the PDMS substrate.

[0023] The spin coating is preferably performed using a spin coater with a three-stage spin coating method, at a maximum spin coating speed of 5000 rpm for 60 seconds.

[0024] The plasma cleaning process is preferably performed using a plasma cleaner for 20 seconds.

[0025] Step 3) Undiluted SU8 photoresist is spin-coated to form a thin film on the upper surface of the PDMS soft substrate.

[0026] Step 4) Expose the area to ultraviolet light under the cover of a strip mask to form areas with alternating soft and hard surfaces.

[0027] The spacing and width of the strip-shaped mask are both 400 μm.

[0028] The ultraviolet exposure uses ultraviolet light with a wavelength of 365nm for 10 seconds, creating a 1:1 width ratio between the exposed and unexposed areas.

[0029] Step 5) Heating and cooling to room temperature will form a wrinkled morphology in the bilayer system.

[0030] The heating is preferably carried out at 110°C for 10 minutes.

[0031] This embodiment relates to a one-dimensional ordered flexible micro / nano-scale wrinkled structure with controllable characteristic parameters prepared by the above method, comprising: an undiluted SU8 / PDMS hard film-soft substrate bilayer system and a one-dimensional ordered wrinkled pattern on its surface. The pattern has a sinusoidal morphology with a wavelength of 29.7 μm and an amplitude of 1.243 μm. Figure 2 As shown in c, its data is shown in Table 1:

[0032] Table 1

[0033] The wavelength and amplitude of the wrinkled structure of the one-dimensional ordered wrinkled pattern vary depending on the dilution ratio of SU8 photoresist to cyclopentanone.

[0034] The one-dimensional ordered wrinkle pattern of SU8 photoresist after dilution of cyclopentanone and SU8 photoresist at a ratio of 1:7 refers to the one-dimensional ordered wrinkle pattern that appears in the hard-film-soft-substrate bilayer system of diluted SU8 / PDMS. Its morphology is sinusoidal, with a wavelength of 26.2 μm and an amplitude of 1.307 μm. Figure 3 As shown in c, the specific data is shown in Table 2.

[0035] Table 2

[0036] The one-dimensional ordered wrinkle pattern of SU8 photoresist after dilution of cyclopentanone and SU8 photoresist at a ratio of 1:4 refers to the one-dimensional ordered wrinkle pattern that appears in the hard-soft substrate bilayer system of diluted SU8 / PDMS. Its morphology is sinusoidal, with a wavelength of 25.8 μm and an amplitude of 1.737 μm. Figure 4 As shown in c, the specific data is shown in Table 3.

[0037] Table 3

[0038] The one-dimensional ordered wrinkle pattern of SU8 photoresist after diluting cyclopentanone and SU8 photoresist at a 1:1 ratio refers to the one-dimensional ordered wrinkle pattern that appears in the diluted SU8 / PDMS hard-film-soft-substrate bilayer system. Its morphology is sinusoidal, with a wavelength of 17.976 μm and an amplitude of 1.120 μm. Figure 5 As shown in c, the specific data is shown in Table 4.

[0039] Table 4

[0040] Compared with existing technologies, this method utilizes a novel hard film material, SU8 photoresist, as the hard film to construct a thin film substrate structure, forming self-destabilizing wrinkles. Furthermore, by using cyclopentanone to prepare SU8 photoresist with different dilution ratios, wrinkle micro / nano structures with controllable wrinkle characteristic parameters (wavelength, amplitude) can be achieved.

[0041] The above-described specific implementations can be partially adjusted by those skilled in the art in different ways without departing from the principles and purpose of the present invention. The scope of protection of the present invention is defined by the claims and is not limited to the above-described specific implementations. All implementation schemes within the scope of the claims are bound by the present invention.

Claims

1. A method for fabricating one-dimensional ordered flexible micro / nano-scale wrinkled structures with controllable characteristic parameters, characterized in that, SU8 photoresists with different dilution ratios were obtained by diluting SU8 with cyclopentanone and then spin-coated onto a PDMS substrate using a three-stage spin-coating method. After exposure and heating, a one-dimensional ordered flexible micro / nano wrinkled structure was obtained, specifically including: Step 1) Mix the PDMS substrate and curing agent at a mass ratio of 10:1 to prepare the PDMS substrate, and cut the PDMS substrate into 8×8mm pieces; Step 2) Clean the PDMS substrate with a plasma cleaner for 20 seconds to change the wettability of PDMS, so that SU8 can be spin-coated onto the PDMS substrate. Step 3) Diluted SU8 photoresist is spin-coated onto the upper surface of the PDMS soft substrate to form a thin film layer; Step 4) Expose the area to ultraviolet light under the cover of a strip-shaped mask to form areas with alternating soft and hard surfaces; Step 5) Heating and cooling to room temperature will form a wrinkled morphology in the bilayer system.

2. The method for fabricating a one-dimensional ordered flexible micro / nano controllable characteristic parameter wrinkled structure according to claim 1, characterized in that, The aforementioned one-dimensional order refers to a periodic wavy pattern.

3. The method for fabricating a one-dimensional ordered flexible micro / nano controllable characteristic parameter wrinkled structure according to claim 2, characterized in that, The wavelength of the periodic wave pattern is 29.7 μm and the amplitude is 1.243 μm.

4. The method for fabricating a one-dimensional ordered flexible micro / nano controllable characteristic parameter wrinkled structure according to claim 1, characterized in that, The different dilution ratios refer to: diluting SU8 photoresist with cyclopentanone, and mixing the cyclopentanone solution and SU8 photoresist at different volume ratios by shaking to form a homogeneous solution.

5. The method for fabricating a one-dimensional ordered flexible micro / nano controllable characteristic parameter wrinkled structure according to claim 1, characterized in that, The spin coating is performed using a spin coater with a three-stage spin coating method, at a maximum spin coating speed of 5000 rpm, for 60 seconds.

6. The method for fabricating a one-dimensional ordered flexible micro / nano controllable characteristic parameter wrinkled structure according to claim 1, characterized in that, The plasma cleaning process involves using a plasma cleaner for 20 seconds.

7. The method for fabricating a one-dimensional ordered flexible micro / nano controllable characteristic parameter wrinkled structure according to claim 1, characterized in that, The spacing and width of the strip-shaped mask are both 400 μm.

8. The method for fabricating a one-dimensional ordered flexible micro / nano controllable characteristic parameter wrinkled structure according to claim 1, characterized in that, The ultraviolet exposure uses ultraviolet light with a wavelength of 365nm for 10 seconds, creating a 1:1 width ratio between the exposed and unexposed areas.

9. The method for fabricating a one-dimensional ordered flexible micro / nano controllable characteristic parameter wrinkled structure according to claim 1, characterized in that, The heating mentioned refers to heating at 110℃ for 10 minutes.

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