Azobenzene polymer material and its application in nanoimprint lithography

Abstract

The present invention discloses an azobenzene polymer material and its application in nanoimprint lithography. The present invention utilizes a simple, one-step ring-opening metathesis polymerization method to prepare the azobenzene polymer, endowing it with excellent thermal and photostability, capable of maintaining its superior performance under high-temperature and sunlight conditions. Compared to conventional nanoimprint photoresists, the nanoimprint photoresist of the present invention exhibits higher stability and precision during the nanoimprint process, effectively reducing issues such as imprinted pattern distortion and blurring, and ensuring the accuracy of nanostructure transfer. This improves product quality and production efficiency while reducing uncertainty and costs in the manufacturing process.

Description

Technical Field

[0001] The invention belongs to the technical field of photoresponsive polymer materials and nanoimprint lithography, and particularly relates to an azobenzene polymer material and application thereof in nanoimprint lithography. Background Art

[0002] With the rapid development of nanotechnology, nanoimprint lithography (NIL) has become a key technology in micro-nanofabrication due to its high resolution, low cost, and high efficiency. It is widely used in semiconductor manufacturing, optoelectronics, sensors, nanomaterials, and other fields. Nanoimprint lithography transfers fine patterns from a mold to a nanoimprint resist through mechanical imprinting. Therefore, the performance of the nanoimprint resist directly affects the transfer quality and accuracy of the pattern, as well as the reliability of the final product. In the NIL process, the nanoimprint resist must not only have excellent pattern replication capabilities but also maintain excellent performance stability under complex environments such as high temperatures and sunlight.

[0003] However, while existing nanoimprint photoresists (such as thermosetting resins and photocurable resins) can meet basic pattern transfer requirements under certain conditions, their stability is significantly insufficient, becoming a bottleneck restricting the development of the technology. First, traditional nanoimprint photoresists are prone to thermal degradation or crosslinking in high-temperature environments, affecting their performance and, in turn, the quality and precision of the pattern during nanoimprinting. Furthermore, nanoimprint photoresists are highly sensitive to light and are prone to photodegradation and performance degradation when exposed to UV light or sunlight for extended periods, resulting in blurred or distorted pattern details during nanoimprinting. Furthermore, many existing photoresists are susceptible to environmental factors (such as humidity and oxygen in the air) during storage and transportation, causing polymerization or decomposition reactions, resulting in changes in the chemical properties of the photoresist and affecting the quality and consistency of the finished product. These stability issues not only limit the application of existing photoresists in high-precision, high-reliability manufacturing but also significantly increase the complexity and cost of production.

[0004] Therefore, developing a nanoimprint photoresist with excellent stability and high precision has become the key to improving the quality of NIL process, reducing production costs and promoting the development of high-end manufacturing technology. Summary of the Invention

[0005] The present invention provides an azobenzene polymer material and its application in nanoimprint lithography, so as to solve the problem that existing nanoimprint photoresists may undergo polymerization, degradation or performance changes under high temperature or light irradiation conditions, resulting in pattern distortion or unstable quality during imprinting. The material is compatible with various micro-nano processing technologies and can economically and efficiently realize high-precision patterns with critical dimensions less than 25 nanometers.

[0006] The method for preparing the azobenzene polymer material of the present invention comprises the following steps:

[0007] Step 1: A coupling reaction is performed on the aromatic amine compound represented by Formula I-a to obtain a compound represented by Formula I-b;

[0008] Step 2: reacting the compound represented by formula I-b with the halohydrin represented by formula I-c to obtain the compound represented by formula I-d;

[0009] Step 3: reacting the compound represented by formula I-e with I-f to obtain the compound represented by formula I-g;

[0010] Step 4: Esterification reaction of the compound represented by formula I-g with I-d to obtain the compound represented by formula I-h;

[0011] Step 5: The compound represented by Formula I-h is subjected to a ring-opening metathesis polymerization reaction to obtain a photoinduced solid-liquid transition azobenzene polymer, the general structure of which is shown in Formula I below.

[0012]

[0013] Where n represents the degree of polymerization, which ranges from 5 to 500. The molecular weight is preferably around 20,000.

[0014] Specifically, the reaction process of each step includes the following:

[0015] Step 1: In an ice-water bath, dissolve compound I-a in concentrated hydrochloric acid, tetrahydrofuran, and ice water. Slowly add sodium nitrite solution dropwise and stir at -5 to 0°C for 30 minutes to generate the diazonium salt. In a separate beaker, dissolve phenol in sodium hydroxide, sodium bicarbonate, and ice water and slowly add the diazonium salt dropwise. Stir the reaction mixture for 2 hours and slowly warm to room temperature. Neutralize with hydrochloric acid to a pH of approximately 6. Filter the crude product, then wash with water. Dry the crude product, dissolve it in a small amount of toluene, and slowly add a large amount of n-hexane for recrystallization to obtain the compound represented by Formula I-b.

[0016] Step 2: Potassium carbonate, compound I-b, potassium iodide, compound I-c, and a magnetite were added to a flask and dissolved in N,N-dimethylformamide. The mixture was stirred vigorously at 110°C for 12 hours. The resulting mixture was cooled to room temperature and extracted with dichloromethane. The organic phase was collected. The solvent was removed using a rotary evaporator to obtain a crude product. The crude product was dissolved in dichloromethane and slowly recrystallized by adding a large amount of toluene to obtain the compound represented by Formula I-d.

[0017] Step 3: Add Compound I-e, Compound I-f, triethylamine, and toluene to a round-bottom flask equipped with a magnetic bar and a reflux condenser. Stir the mixture at 110°C for 19 hours, cool to room temperature, and remove the solvent using a rotary evaporator. Dissolve the remaining solid in dichloromethane, wash three times with distilled water, then three times with a saturated sodium chloride solution, and dry over anhydrous sodium sulfate. Filter and remove the solvent using a rotary evaporator to yield the compound represented by Formula I-g.

[0018] Step 4: Add Compound I-d, Compound I-g, 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride, N,N-diisopropylethylamine, 4-dimethylaminopyridine, dichloromethane, and a magnetic particle to a round-bottom flask and stir at room temperature for 24 hours. The reaction solution is washed three times with distilled water and three times with saturated sodium chloride solution, and dried over anhydrous sodium sulfate. After filtration, the solvent is removed using a rotary evaporator to obtain a crude yellow solid. Dissolve the solid in tetrahydrofuran and slowly add a large amount of methanol for recrystallization. Filter and obtain the compound represented by Formula I-h.

[0019] Step 5: Add compound I-h to a reaction tube. After three purges of nitrogen in the glove box transition chamber, place the tube back into the glove box. Add Grubbs's third catalyst, anhydrous dichloromethane, and a magnet. Stir the reaction at room temperature for 5 minutes. Add vinyl ethyl ether to terminate the reaction. Continue stirring for 15 minutes, remove from the glove box, dilute the reaction solution with tetrahydrofuran, and pass it through a basic alumina chromatography column to remove any residual Grubbs's third catalyst. After removing the solvent using a rotary evaporator, dissolve the polymer in a small amount of tetrahydrofuran and slowly add it dropwise to rapidly stirring methanol to precipitate the polymer. Centrifuge and discard the supernatant. Repeat the dissolution-precipitation steps twice more. Dry the mixture to obtain the polymer represented by Formula I.

[0020] Application of the azobenzene polymer material of the present invention in nanoimprint lithography.

[0021] Specifically, nanoimprinting is performed using the azobenzene polymer material as an imprint photoresist, comprising the following steps:

[0022] The azobenzene polymer material is dissolved in cyclopentanone to form a solution, and the solution is spin-coated on a square glass slide. The solvent is evaporated to obtain a nanoimprint film; the nanoimprint film is irradiated with ultraviolet LED light to liquefy the polymer film, and a certain pressure is applied to the nanoimprint mold with a microstructure so that the liquefied polymer fills the microstructure of the imprint mold. The nanoimprint mold and sample that have been fully in contact are placed in a vacuum oven for a period of time, and the residual air in the imprinted structure is removed at room temperature. Then, visible light LED light is used to solidify the polymer film, and the corresponding nanostructure is obtained after the imprint mold is removed.

[0023] The azobenzene polymer material is dissolved in cyclopentanone to form a solution, and the concentration of the polymer in the cyclopentanone is 20 mg / mL.

[0024] The wavelength of the ultraviolet LED is 365 nm, and the wavelength of the visible light LED is 530 nm.

[0025] The nano-pattern obtained by the nano-imprinting has a multi-scale structure. The surface of the obtained nano-structure is subjected to gold spraying, and the nano-pattern is observed using a scanning electron microscope.

[0026] The present invention also provides a method for using the azobenzene polymer for nanoimprinting, and studies the stability and imprinting accuracy of the azobenzene polymer as a nanoimprinting photoresist.

[0027] The azobenzene polymer nanoimprint photoresist of the present invention exhibits excellent stability and high precision. The azobenzene polymer was subjected to different heat and sunlight exposure treatments (no treatment, treatment at 50°C for 1 hour, treatment at 100°C for 1 hour, treatment at 150°C for 1 hour, and sunlight exposure for 48 hours), and its performance as a nanoimprint photoresist was tested by nanoimprinting. The azobenzene polymer's performance as a nanoimprint photoresist remained unchanged after the different treatments.

[0028] In summary, the azobenzene polymer provided by the present invention can be used as a nanoimprint photoresist to simply and quickly develop a nanoimprint photoresist with excellent stability. At the same time, the nanoimprint photoresist has high imprint accuracy.

[0029] Compared with existing nanoimprint photoresists, the advantages of the present invention are specifically reflected in:

[0030] 1. The present invention uses ring-opening metathesis polymerization to prepare azobenzene polymer as a nanoimprint photoresist, and the preparation method is simple; the selected azobenzene polymer has a simple structure, and the raw materials are readily available, which is suitable for large-scale production.

[0031] 2. The azobenzene polymer of the present invention has excellent thermal stability and light stability when used as a nanoimprint photoresist, and can meet the needs of daily transportation, storage and use of daily nanoimprint photoresists.

[0032] 3. The azobenzene polymer of the present invention has high imprinting precision when used as a nanoimprint photoresist, making it crucial in many high-tech fields, especially semiconductors, optoelectronics, medical equipment, display technology, optical devices and quantum computing. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] The accompanying drawings are part of this application and are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention, but do not constitute an undue limitation of the present invention. Obviously, the drawings described below are only some embodiments. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without inventive effort. In the accompanying drawings:

[0034] Figure 1 UV-visible absorption spectrum of the prepared azobenzene polymer film.

[0035] Figure 2 This is a comparison chart of gel permeation chromatography of the prepared azobenzene polymer and the azobenzene polymer after different treatments.

[0036] Figure 3 This is a comparison chart of the hydrogen nuclear magnetic resonance spectra of the prepared azobenzene polymer and the azobenzene polymer after different treatments.

[0037] Figure 4 This is a comparison chart of the total reflection infrared spectra of the prepared azobenzene polymer and the azobenzene polymer after different treatments.

[0038] Figure 5 Scanning electron micrograph of the prepared azobenzene polymer with high-precision patterns prepared by nanoimprinting.

[0039] Figure 6 Scanning electron micrograph of the prepared azobenzene polymer without nanoimprinting.

[0040] Figure 7 This is a scanning electron microscopy image of the nanoimprint of the prepared azobenzene polymer after treatment at 50°C for 1 hour.

[0041] Figure 8 This is a scanning electron microscopy image of the nanoimprint of the prepared azobenzene polymer after treatment at 100°C for 1h.

[0042] Figure 9 This is a scanning electron microscopy image of the nanoimprint of the prepared azobenzene polymer after treatment at 150°C for 1h.

[0043] Figure 10 This is a scanning electron microscope image of the nanoimprint of the prepared azobenzene polymer after being treated with sunlight for 48 hours.

[0044] It should be noted that these drawings and textual descriptions are not intended to limit the conceptual scope of the present invention in any way, but rather to illustrate the concept of the present invention for those skilled in the art by referring to specific embodiments. DETAILED DESCRIPTION

[0045] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. The following embodiments are used to illustrate the present invention but are not used to limit the scope of the present invention.

[0046] Example 1: Preparation of Compound I-b

[0047] To a 500 mL beaker, add 4-decylaniline (9 g, 38.55 mmol), 9 mL of concentrated hydrochloric acid (36%), ice (10 g), water (20 mL), a magnet, and tetrahydrofuran (20 mL). Stir vigorously to dissolve the solution and place in an ice-salt bath. To a separate 100 mL beaker, add water (10 mL), ice (5 g), and sodium nitrite (2.88 g, 41.73 mmol). Stir thoroughly to dissolve the solution and slowly add the solution dropwise to the aniline solution. Stir at -5 to 0°C for 30 min to generate the diazonium salt. To a separate 500 mL beaker, add phenol (3.96 g, 42.09 mmol), sodium hydroxide (1.8 g, 45.0 mmol), sodium bicarbonate (5.4 g, 9.06 mmol), ice (10 g), and water (20 mL) and slowly add the diazonium salt dropwise. The reaction mixture was stirred for 2 hours and slowly warmed to room temperature. The mixture was neutralized with hydrochloric acid to a pH of approximately 6 and then filtered and washed with water. The crude product was dried, dissolved in a small amount of toluene (10 mL), and recrystallized by slowly adding a large amount of n-hexane (200 mL). Compound I-b was obtained as a reddish-brown solid. The yield was 80.1%.

[0048] Example 2: Preparation of Compound I-d

[0049] A 250 mL flask was charged with potassium carbonate (6.12 g, 44.28 mmol), compound I-b (12.5 g, 36.9 mmol), potassium iodide (306 mg, 1.845 mmol), 6-chloro-1-hexanol (6.03 g, 44.4 mol), and a magnet. N,N-dimethylformamide (60 mL) was added as solvent and the reaction was stirred vigorously at 110°C for 12 h. The resulting mixture was cooled to room temperature and extracted with dichloromethane (150 mL). The organic phase was collected. The solvent was removed using a rotary evaporator to obtain the crude product. The crude product was dissolved in dichloromethane (10 mL) and slowly added with toluene (200 mL) for recrystallization and purification. Compound I-d was obtained as a reddish-brown solid with a yield of 83.1%.

[0050] Example 3: Preparation of Compound I-g

[0051] cis-5-norbornene-exo-2,3-dicarboxylic anhydride (8.2 g, 50.0 mmol), 6-aminohexanoic acid (6.55 g, 50 mmol), triethylamine (0.7 mL, 5.0 mmol), and toluene (100 mL) were added to a round-bottom flask equipped with a magnetic bar and a reflux condenser. The mixture was stirred at 110°C for 19 h, cooled to room temperature, and the solvent was removed using a rotary evaporator. The remaining solid was dissolved in dichloromethane (200 mL), washed three times with distilled water (200 mL), then three times with saturated sodium chloride solution (200 mL), and dried over anhydrous sodium sulfate. After filtration, the solvent was removed using a rotary evaporator to obtain compound I-g as a white solid. The yield was 90.5%.

[0052] Example 4: Preparation of Compound I-h

[0053] Compound I-g (9.15 g, 33.0 mmol), compound 3-7 (10.65 g, 30.0 mmol), 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride (6.9 g, 36.0 mmol), N,N-diisopropylethylamine (5.94 mL, 36.0 mmol), 4-dimethylaminopyridine (0.33 g, 3.0 mmol), dichloromethane (150 mL), and a magnetic separator were added to a 500 mL round-bottom flask. The reaction was stirred at room temperature for 24 h. The reaction solution was washed three times with distilled water (200 mL) and three times with saturated sodium chloride solution (200 mL), and then dried over anhydrous sodium sulfate. After filtration, the solvent was removed using a rotary evaporator to obtain a crude yellow solid. The solid was dissolved in tetrahydrofuran (30 mL) and slowly recrystallized by adding methanol (500 mL). After filtration and drying, compound I-h was obtained as a reddish-brown solid with a yield of 81%.

[0054] Example 5: Preparation of Azobenzene Polymer I (n=30)

[0055] Compound I-h (1000 mg) and a magnetic particle were added to a reaction tube. After three purgings of nitrogen in the transition chamber, the tube was placed in a glove box and 4.0 mL of anhydrous dichloromethane was added to dissolve the monomer. In another vial in the glove box, Grubbs's third catalyst (53.2 mg) and dichloromethane (600 μL) were added. 400 μL of the Grubbs's third catalyst solution was rapidly added to the reaction tube. After 5 minutes of reaction, the reaction was terminated by the addition of 5 drops of ethyl vinyl ether. Stirring was continued for 15 minutes before removal from the glove box. The reaction solution was diluted with tetrahydrofuran and passed through a basic alumina chromatography column to remove any residual Grubbs's third catalyst. After removing the solvent using a rotary evaporator, the polymer was dissolved in 4 mL of tetrahydrofuran and slowly added dropwise to 80 mL of rapidly stirring methanol to precipitate the polymer. Centrifuge at 10,000 rpm for 5 minutes, and the supernatant was discarded. The dissolution-precipitation procedure was repeated two more times. The solid was dried in a vacuum oven at 45°C for 12 hours. Polymer I was obtained as a yellow solid with a yield of 92%.

[0056] Example 6:

[0057] The azobenzene polymer is subjected to different treatments, and the specific steps are as follows:

[0058] The azobenzene polymer solid obtained in Example 5 was divided into five equal portions by mass. The first portion of the azobenzene polymer was stored in the dark at room temperature. The second portion of the azobenzene polymer was oven-cured at 50°C for 1 hour. The third portion of the azobenzene polymer was oven-cured at 100°C for 1 hour. The fourth portion of the azobenzene polymer was oven-cured at 150°C for 1 hour. The fifth portion of the azobenzene polymer was exposed to sunlight for 48 hours and then oven-cured at 40°C for 8 hours.

[0059] Example 7:

[0060] Gel permeation chromatograms of the azobenzene polymer in Test Example 5 initially and after different treatments.

[0061] Figure 2 is the gel permeation chromatogram of the azobenzene polymer after different treatments prepared in Example 5. Figure 2 It can be seen that the number average molecular weight of the first azobenzene polymer is 27880, and the polymerization distribution index is 1.13. The number average molecular weight of the second azobenzene polymer is 28610, and the polymerization distribution index is 1.13. The number average molecular weight of the third azobenzene polymer is 28442, and the polymerization distribution index is 1.15. The number average molecular weight of the fourth azobenzene polymer is 28296, and the polymerization distribution index is 1.18. The number average molecular weight of the fifth azobenzene polymer is 28103, and the polymerization distribution index is 1.14. From Figure 2 It can be seen that the molecular weight and molecular weight distribution of azobenzene polymer remain basically unchanged after different treatments.

[0062] Example 8:

[0063] H NMR spectra of the azobenzene polymer in Test Example 5, initially and after different treatments.

[0064] Figure 3 The following are the H NMR spectra of the azobenzene polymers prepared in Example 5 after different treatments. Figure 3 It can be seen that the polymer structure of azobenzene polymer remains unchanged after different treatments.

[0065] Example 9:

[0066] Total reflection infrared spectra of the azobenzene polymer in Test Example 5 initially and after different treatments.

[0067] Figure 4 The total reflection infrared spectra of the azobenzene polymers prepared in Example 5 after different treatments are shown in FIG. Figure 4 It can be seen that the polymer structure of azobenzene polymer remains unchanged after different treatments.

[0068] Example 10:

[0069] Prepare nanoimprintable azobenzene polymer films. The specific steps are as follows:

[0070] Take five parts of the azobenzene polymer from Example 6, then weigh 20 mg of each of the five parts of azobenzene polymer solid and dissolve them in 1 mL of cyclopentanone to form a solution. Finally, spin-coat the solution on a square glass slide and place it in a vacuum oven overnight to evaporate the solvent, thereby obtaining an azobenzene polymer film that can be nanoimprinted.

[0071] Example 11:

[0072] The ultraviolet-visible absorption spectrum of the nano-imprintable azobenzene polymer film prepared in Example 10 was tested under different external light conditions.

[0073] Figure 1 The UV-visible absorption spectrum of the untreated azobenzene polymer film prepared in Example 10 in the range of 250 nm to 800 nm. Figure 1 As can be seen in the figure, under 365 nm UV LED irradiation, the π-π* absorption peak of the azobenzene polymer film decreases while the n-π* absorption peak increases, indicating a transition from a trans- to a cis-structure. Subsequently, under 530 nm visible light LED irradiation, the π-π* absorption peak increases while the n-π* absorption peak decreases, indicating a reversion of the cis-structure of azobenzene to a trans-structure.

[0074] Example 12: Nanoimprinting Experiment

[0075] The untreated azobenzene polymer film obtained in Example 10 was irradiated with ultraviolet LED light (365 nm) for 5 min to liquefy the polymer film; a grating-type PDMS mold (period of 125 nm, stripe width of 25 nm) was used to imprint the film. After sufficient contact, the film was placed in a vacuum oven at room temperature for 15 min to remove the air remaining in the imprinted structure. The polymer film was then irradiated with visible light LED light (530 nm) through the PDMS mold for 5 min to solidify the polymer film. After removing the PDMS mold, the corresponding nanostructure was obtained.

[0076] The five types of azobenzene polymer films obtained in Example 10 were taken and irradiated with ultraviolet LED light (365 nm) for 5 min to liquefy the polymer film; a grating-type PDMS mold (period of 500 nm, stripe width of 200 nm) was used to imprint the film. After sufficient contact, the film was placed in a vacuum oven and evacuated at room temperature for 15 min to remove the air remaining in the imprinted structure. The PDMS mold was then irradiated with visible light LED light (530 nm) for 5 min to solidify the polymer film. After removing the PDMS mold, the corresponding nanostructure was obtained.

[0077] Example 13:

[0078] Scanning electron microscope image of the nanostructure obtained by nanoimprinting of the azobenzene polymer film in Test Example 12.

[0079] Figure 5 This is a scanning electron micrograph of a high-precision pattern obtained by nanoimprinting of the untreated azobenzene polymer film prepared in Example 12. The results show that the azobenzene polymer can be used as a nanoimprint photoresist to obtain high-precision patterns.

[0080] Figures 6-10 Scanning electron micrographs of the structures of the five types of azobenzene polymer films prepared by nanoimprinting in Example 12. The results show that the azobenzene polymer has excellent stability when used as a nanoimprint photoresist.

[0081] The above description is merely a preferred embodiment of the present invention and does not constitute any form of limitation to the present invention. Although the present invention has been disclosed as above in terms of a preferred embodiment, it is not intended to limit the present invention. Any technician familiar with this patent can make slight changes or modifications to equivalent embodiments using the above technical content without departing from the scope of the technical solution of the present invention. However, any simple modifications, equivalent changes, and modifications made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solution of the present invention are still within the scope of the solution of the present invention.

Claims

1. An azobenzene polymer material, characterized in that Its general structural formula is shown in the following formula I: ； Where n represents the degree of polymerization, which ranges from 5 to 500.

2. The method for preparing the azobenzene polymer material according to claim 1, characterized in that The steps include: Step 1: A coupling reaction is performed on the aromatic amine compound represented by Formula I-a to obtain a compound represented by Formula I-b; Step 2: reacting the compound represented by formula I-b with the halohydrin represented by formula I-c to obtain the compound represented by formula I-d; Step 3: reacting the compound represented by formula I-e with I-f to obtain the compound represented by formula I-g; Step 4: Esterification reaction of the compound represented by formula I-g with I-d to obtain the compound represented by formula I-h; Step 5: performing a ring-opening metathesis polymerization reaction on the compound represented by Formula I-h to obtain a photoinduced solid-liquid transition azobenzene polymer represented by Formula I; 。 3. Use of the azobenzene polymer material according to claim 1 in nanoimprint lithography.

4. The use according to claim 3, characterized in that: Nanoimprinting is performed using the azobenzene polymer material as an imprint photoresist.

5. The use according to claim 4, characterized in that The steps include: The azobenzene polymer material is dissolved in cyclopentanone to form a solution, the solution is spin-coated on a carrier, and the solvent is evaporated to obtain a nanoimprint film; the nanoimprint film is irradiated with ultraviolet LED light to liquefy the polymer film, a certain pressure is applied to the nanoimprint mold with the microstructure so that the liquefied polymer fills the microstructure of the imprint mold, the residual air in the imprint structure is removed at room temperature, and the polymer film is solidified using visible light LED light. After removing the imprint mold, the corresponding nanostructure is obtained.

6. The use according to claim 5, characterized in that: The azobenzene polymer material is dissolved in cyclopentanone to form a solution, and the concentration of the polymer in the cyclopentanone is 20 mg / mL.

7. The use according to claim 5, characterized in that: The wavelength of the ultraviolet LED is 365 nm.

8. The use according to claim 5, characterized in that: The wavelength of the visible light LED is 530 nm.

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