Method for realizing silver nanocube pattern distribution based on Brush-Mat method

Abstract

The invention discloses a method for realizing silver nanocube pattern distribution based on a Brush-Mat method. The method specifically comprises the following steps: spin-coating a proper substrate with cross-linkable polyethylene; then carrying out heating pretreatment on the substrate to crosslink the crosslinkable polyethylene to obtain stable polyethylene, and taking the stable polyethylene as a Mat material; performing graphical processing on the Mat material; sulfydryl-terminated polyethylene glycol is used as a Brush material, and silver nanocubes are accurately distributed on a substrate according to a pattern on the basis of the Brush material. According to the invention, the positioning of the Ag nano-cube can be actively controlled, the high-resolution, accurate and controllable pattern distribution of the Ag nano-cube can be realized, and the stability of the pattern is ensured.

Description

Technical Field

[0001] The present invention belongs to the technical field of supersurfaces, and in particular relates to a method for realizing silver nanocube pattern distribution based on a Brush-Mat method. Background Art

[0002] In the construction of metasurface materials, precise control of the pattern distribution of nanomaterials is crucial for achieving specific optical, electrical, and other properties. However, existing techniques for controlling the pattern distribution of silver nanocubes (Ag nanocubes) suffer from low precision. Existing techniques for controlling the pattern distribution of Ag nanocubes include traditional photolithography and sputtering, a combination of photolithography and capillary-assisted deposition, random growth, and a combination of both. Traditional photolithography and sputtering suffer from high costs. EBL equipment is not only expensive but also extremely complex to operate, making the entire process extremely time-consuming. Furthermore, the shape of the Ag cubes produced by this method is significantly affected by process fluctuations, making it difficult to ensure consistent shape. More critically, these Ag cubes lack a coating and are easily oxidized in air, severely impacting their performance and lifespan. A combined photolithography and capillary-assisted deposition method combines EBL with silicon mastering to transfer the pattern to a PDMS mold. Capillary-assisted nanoparticle assembly (CAPA) is then used to inject and assemble colloidal, PVP-protected Ag nanocubes into specific locations on the template. This method can achieve single-particle resolution nanoparticle positioning, but the process is still very complex and relies solely on capillary-assisted passive positioning, resulting in low efficiency and poor stability. Random growth, the method of randomly growing Ag nanocubes protected by PVP coating from bottom to top through solution dip coating, although different from traditional methods in preparation, produces a random distribution of Ag nanocubes. This random distribution poses great difficulties for simulation and experimental comparison control, making it difficult to establish an accurate model, making it impossible for researchers to accurately attribute and analyze experimental results, and seriously hindering the in-depth development of related fields such as metamaterials and nano-optics. The combination of lithography and random growth methods is to form large-area patterns through traditional lithography from top to bottom, combined with the local random distribution of Ag nanocubes protected by PVP coating grown from bottom to top through solution dip coating. This achieves precise control of the layout of the bonded Ag nanocubes on multiple length scales (micrometer level). However, the local distribution of the Ag nanocubes is still random, and the accuracy and uniformity of their distribution are difficult to control. In the field of metamaterials research, the Brush-Mat method can be used to precisely control the distribution of gold nanospheres. However, while researchers are continuously refining these methods to improve the quality and controllability of Ag nanocube pattern distribution, there is currently no effective method that can simultaneously address the challenges of high-precision controllable distribution, cost and efficiency, and chemical stability. In fields such as metasurfaces and nano-optics, a mature technology that can achieve bottom-up growth and form high-precision patterned distribution of Ag cubes is urgently needed to meet the demand for high-precision, controllable nanostructures. Currently, this technology is still lacking. Summary of the Invention

[0003] Purpose of the invention: In order to solve the problems existing in the above-mentioned prior art, the present invention provides a method for realizing the distribution of silver nanocube patterns based on the Brush-Mat method.

[0004] Technical solution: The present invention discloses a method for realizing the distribution of silver nanocube patterns based on the Brush-Mat method, which specifically includes the following steps:

[0005] The cross-linkable polyethylene is spin-coated onto a suitable substrate; the substrate is then pre-heated to cross-link the cross-linkable polyethylene to obtain a stable polyethylene, which is used as a Mat material;

[0006] Perform graphic processing on Mat material;

[0007] Thiol-terminated polyethylene glycol is used as the brush material, and based on the brush material, the silver nanocubes are accurately distributed on the substrate according to the pattern.

[0008] Furthermore, based on the Brush material, the silver nanocubes are accurately distributed on the substrate according to the pattern. Specifically, the Brush material is fully mixed with the silver nanocube solution protected by the PVP coating; the silver nanocubes are firmly adsorbed on the thiol-terminated polyethylene glycol; and the Brush material adsorbed with the silver nanocubes is brought into contact with a polyethylene mat with pattern stabilization, so that the silver nanocubes are accurately distributed on the substrate according to the pattern with the help of the Brush material.

[0009] Furthermore, the method also includes an adsorption performance test, specifically: after the Brush material is fully mixed with the silver nanocubes protected by the PVP coating, the reaction is carried out for a period of time T, where T is a preset time. The structural morphology after adsorption is observed using an instrument to evaluate the adsorption effect, and then the energy spectrum analysis method is used to detect the changes in the elemental composition before and after adsorption, and the changes are used to confirm whether the adsorption is firm.

[0010] Furthermore, based on the Brush material, the silver nanocubes are accurately distributed on the substrate according to the pattern. Specifically, the Brush material is spin-coated on a stable polyethylene mat so that the Brush material is positioned only in the patterned area of the mat. Then, annealing treatment is performed in a nitrogen environment to form a Brush-Mat pattern. Then, a silver nanocube solution protected by a PVP coating is deposited so that the silver nanocubes are adsorbed by the Brush material, thereby ensuring that the silver nanocubes are accurately distributed on the substrate according to the pattern.

[0011] Furthermore, photolithography or printing is used for patterning.

[0012] Furthermore, the method for preparing the cross-linkable polyethylene is: monomers, ligands, an appropriate amount of a cross-linking agent and an initiator are uniformly mixed in a preset ratio; the monomers include: styrene, glycidyl methacrylate; the initiator is ethyl α-bromoisobutyrate; and the ligand includes pentamethyldiethylenetriamine.

[0013] Furthermore, the method also includes product testing, specifically: detecting the morphology of the metasurface of the silver nanocubes with a patterned distribution, and testing its chemical properties using a spectrometer; ensuring that the performance indicators of the metasurface of the silver nanocubes with a patterned distribution meet expectations.

[0014] Furthermore, the method also includes testing the adsorption performance of the patterned Mat material surface through an adsorption experiment: placing the prepared silver cube solution on the surface of the Mat material to observe whether adsorption occurs. If there is no adsorption within the specified time, it meets the requirements.

[0015] A super surface material is prepared by the above method.

[0016] Beneficial effects:

[0017] 1) The present invention aims to provide a new and efficient Brush-Mat method to overcome the problems of insufficient controllability of Agnanocube distribution, poor stability and high cost in the prior art. The method actively controls the positioning of Ag nanocubes, and can achieve high-resolution, precisely controllable pattern distribution of Agnanocubes while ensuring the stability of the pattern; including arbitrary sizes and arbitrary shapes, reaching nanoscale distribution. Compared with the previous randomly distributed Ag cubes, the present invention can carry out experiments with more controllable positions, such as perfect attraction, second-order resonance generation, third-order resonance generation, laser generation, etc., providing a high-performance and highly controllable nanomaterial preparation solution for research in related fields, thereby meeting the high performance requirements of metasurface materials in different application fields (such as optical filters, sensors, etc.).

[0018] 2) The periodic or randomly distributed Agnanocube metasurface structure prepared by the present invention maintains strict consistency with the simulation model, thereby accelerating the optimization process, effectively promoting the research progress of metamaterials and related fields, and promoting the development and application of new metasurface materials.

[0019] 3) This invention utilizes a relatively simple and low-cost Brush-Mat method, avoiding the expensive EBL equipment and complex processes, thus reducing production costs. Furthermore, the PVP coating protects the Agnanocube and precisely controls its distribution, effectively improving the material's stability and performance, extending its service life. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 Schematic diagram of the process flow for testing the non-adsorption of X-PS "Mat" to AgNanocube;

[0021] Figure 2 Schematic diagram of the process flow chart for the experiment of detecting Thiol-PEG “Brush” adsorption on AgNanocube;

[0022] Figure 3 Flowchart for implementation one;

[0023] Figure 4 SEM images of Ag-Nanocube patterned for Brush-Mat functional verification;

[0024] Figure 5 This is a flow chart of Example 2. DETAILED DESCRIPTION

[0025] The accompanying drawings, which constitute a part of the present invention, 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 and do not constitute improper limitations on the present invention.

[0026] The present invention selects cross-linkable polyethylene (X-PS) as the Mat material. This material has the property of not attracting (inert) the Agnanocube, which can ensure that the distribution of the Agnanocube will not be disturbed during subsequent operations, providing a stable foundation for the precise distribution of the Agnanocube. The experimental process and results of testing the inert property of cross-linkable polyethylene for Agnanocube are shown in the following figure. Figure 1 shown.

[0027] Thiol-terminated PEG (thiol-terminated polyethylene glycol) is used as the brush material. The thiol group at one end of the brush has strong reactivity and can effectively interact with the silver nanocubes protected by the PVP coating to achieve adsorption of the silver nanocubes, thereby achieving precise graphical distribution on the Mat. The process flow and results of the experiment to detect the adsorption of Thiol-terminated PEG on AgNanocube are shown below. Figure 2 shown.

[0028] Example 1, as Figure 3 As shown, the specific steps of the present invention are:

[0029] a) Mat Pretreatment and Patterning: X-PS is spin-coated onto a suitable substrate (such as a metal film or Si film) and pre-heated in an oven to crosslink it, forming a stable polyethylene Mat. Specific processes such as photolithography or printing are then used to form a specific pattern on the Mat substrate. During the crosslinking process, the progress of the crosslinking reaction is monitored using methods such as infrared spectroscopy (FTIR).

[0030] b) Brush-Agnanocube Bonding: Thiol-terminated PEG is reacted with PVP-coated silver nanocubes at a specific temperature (e.g., room temperature) and under stirring for a specific time to allow the silver nanocubes to fully adsorb onto the thiol-terminated PEG. The adsorption properties of the thiol groups in the thiol-terminated PEG allow the silver nanocubes to be firmly attached to the brush. During this process, the thiol groups may chemically react with the PVP coating on the silver nanocube surface, or form a strong physical adsorption interaction.

[0031] c) Realization of pattern distribution: The brush adsorbed with silver nanocubes is brought into contact with the mat on which a pattern has been formed. The interaction between the brush and the mat is utilized to enable the silver nanocubes to be accurately distributed on the substrate according to the pattern of the mat with the help of the brush.

[0032] d) Post-processing and stability assurance: The distributed silver nanocubes are then subjected to subsequent processing operations such as cross-linking and fixation to ensure the stability of their distribution and prevent displacement or shedding during subsequent applications. Further chemical treatment or physical means can be used to enhance the bonding between the silver nanocubes, the brush, and the mat.

[0033] Preparation process of cross-linkable polyethylene: Various monomers of cross-linkable polyethylene are mixed evenly with appropriate amounts of cross-linking agents, initiators, etc. in a certain proportion, and polymerization reaction is carried out to form cross-linkable polyethylene. This synthesis process is mainly based on atom transfer radical polymerization (ATRP). The chemical components include monomer styrene (styrene), monomer glycidyl methacrylate (glycidyl methacrylate GMA), initiator ethyl α-bromoisobutyrate ((CH3)2CBrCOOC2H5), and ligand N,N,N′,N″,N″-pentamethyldiethylenetriamine (pentamethyldiethylenetriamine PMDTA), etc., of which the content of GMA is 4%.

[0034] The patterning process in step a) is specifically as follows: when patterning is performed using a photolithography process, a layer of photoresist is first spin-coated on the surface of the cross-linked polyethylene, and the designed pattern is transferred to the photoresist through steps such as mask exposure and development. Then, a plasma etching process is used to etch the pattern into the polyethylene layer. If printing technology is used, screen printing, inkjet printing, etc. can be selected to directly print the cross-linkable polyethylene material into the desired pattern.

[0035] In the present embodiment, if Thiol-terminated PEG is a finished product purchased, it needs to be subjected to purity testing and quality assessment. Analytical methods such as high performance liquid chromatography (HPLC) can be used to detect whether its purity meets the requirements and to check whether the activity of the sulfhydryl group is normal. If it is synthesized voluntarily, polyethylene glycol is used as a raw material and a sulfhydryl group is introduced at one end thereof by a suitable chemical reaction. For example, polyethylene glycol is reacted with a reagent containing a sulfhydryl group in the presence of a catalyst, and the reaction temperature, time, and raw material ratio are accurately controlled. After the reaction is completed, it is purified by methods such as column chromatography.

[0036] This embodiment also includes an adsorption performance test of a mixture of Brush and Ag nanocube: the prepared Thiol-terminated PEG is mixed with the silver nanocube protected by the PVP coating, and the mixture is reacted for a period of time under a certain temperature and stirring condition so that the silver nanocube is fully adsorbed on the Thiol-terminated PEG. The structural morphology after adsorption is observed using instruments such as a scanning electron microscope (SEM), a transmission electron microscope (TEM) or an atomic force microscope (AFM), and the adsorption effect is evaluated to ensure that the silver nanocube is uniformly and firmly adsorbed on the "Brush". The changes in the elemental composition before and after adsorption can be detected by means such as energy spectrum analysis to further confirm the adsorption situation. The two can also be spin-coated onto a substrate film (such as a metal film or a Si film, etc.) to check their adsorption on the Nanocube under the super surface condition.

[0037] When a thiol-terminated PEG brush adsorbed with silver nanocubes is brought into contact with a polyethylene mat with a pattern formed thereon, the contact time and pressure are controlled. At room temperature, the brush is gently pressed to ensure full contact for a specific number of minutes. Utilizing weak interaction forces such as van der Waals forces and hydrogen bonds between the brush and the mat, the silver nanocubes are distributed on the substrate according to the pattern of the mat with the help of the brush.

[0038] This example also includes performance testing of the patterned polyethylene "Mat," primarily to examine its lack of attraction to Ag nanocubes. This can be verified through a simple adsorption experiment: a small amount of prepared Ag nanocubes is placed on the "Mat" surface and observed for adsorption using a dark-field microscope or spectrometer. If no significant adsorption occurs within a certain period of time, the material meets the requirements.

[0039] The prepared metasurface with patterned Ag nanocubes is thoroughly inspected, including using scanning electron microscopy (SEM) or atomic force microscopy (AFM) to examine its surface morphology and using FTIR spectrometers to test its optical properties, to ensure that the product meets the expected performance indicators. Furthermore, accelerated aging experiments can be used to evaluate the product's stability and service life.

[0040] The SEM image of the Brush-Mat patterned Ag-Nanocube functional verification in this embodiment is shown in the figure below: Figure 4 shown

[0041] Example 2, as Figure 5 As shown, Example 2 is identical to steps a) and d) in Example 1. Regarding steps c) and b), Example 2 first spin-coats a brush solution onto a sample already patterned with a mat, positioning the brush only in areas without a mat-shaped three-dimensional pattern. Annealing is then performed in a nitrogen atmosphere to form a brush-mat pattern. Subsequently, a solution containing Ag nanocubes is brought into contact with the sample, allowing the Ag nanocubes to be captured by the brush, thereby forming a specific Ag nanocube distribution.

[0042] It should also be noted that the various specific technical features described in the above specific embodiments can be combined in any appropriate manner without contradiction. To avoid unnecessary repetition, the present invention will not further describe various possible combinations.

Claims

1. A method for achieving silver nanocube pattern distribution based on the Brush-Mat method, characterized in that: The specific steps include: The cross-linkable polyethylene is spin-coated onto a suitable substrate; the substrate is then pre-heated to cross-link the cross-linkable polyethylene to obtain a stable polyethylene, which is used as a Mat material; Perform graphic processing on Mat material; Thiol-terminated polyethylene glycol is used as the brush material, and based on the brush material, the silver nanocubes are accurately distributed on the substrate according to the pattern.

2. The method for achieving silver nanocube pattern distribution based on the Brush-Mat method according to claim 1, characterized in that: The silver nanocubes are accurately distributed on the substrate according to a pattern based on the brush material. Specifically, the brush material is fully mixed with a silver nanocube solution protected by a PVP coating; the silver nanocubes are firmly adsorbed on thiol-terminated polyethylene glycol; and the brush material adsorbed with the silver nanocubes is brought into contact with a polyethylene mat with pattern stabilization, so that the silver nanocubes are accurately distributed on the substrate according to a pattern with the help of the brush material.

3. The method for achieving silver nanocube pattern distribution based on the Brush-Mat method according to claim 2, characterized in that: The method also includes an adsorption performance test, specifically: after the Brush material is fully mixed with the silver nanocubes protected by the PVP coating, the reaction is carried out for a period of time T, where T is a preset time. The structural morphology after adsorption is observed using an instrument to evaluate the adsorption effect, and then the energy spectrum analysis method is used to detect the changes in the elemental composition before and after adsorption, and the changes are used to confirm whether the adsorption is firm.

4. The method for achieving silver nanocube pattern distribution based on the Brush-Mat method according to claim 1, characterized in that: The method involves spin-coating the brush material onto a stable polyethylene mat, positioning the brush material only in the patterned area of the mat. The material is then annealed in a nitrogen atmosphere to form a brush-mat pattern. A silver nanocube solution protected by a PVP coating is then deposited, allowing the silver nanocubes to be adsorbed by the brush material and accurately distributed on the substrate according to the pattern.

5. The method for achieving silver nanocube pattern distribution based on the Brush-Mat method according to claim 1, characterized in that: Patterning is performed using photolithography or printing.

6. The method for achieving silver nanocube pattern distribution based on the Brush-Mat method according to claim 1, characterized in that: The cross-linkable polyethylene preparation method comprises: uniformly mixing monomers, ligands, an appropriate amount of cross-linking agent and an initiator in a preset ratio; the monomers include styrene and glycidyl methacrylate; the initiator is ethyl α-bromoisobutyrate; and the ligand includes pentamethyldiethylenetriamine.

7. The method for achieving silver nanocube pattern distribution based on the Brush-Mat method according to claim 1, characterized in that: The method also includes product testing, specifically: detecting the morphology of the metasurface of the silver nanocubes with a patterned distribution and testing its chemical properties using a spectrometer; ensuring that the performance indicators of the metasurface of the silver nanocubes with a patterned distribution meet expectations.

8. The method for achieving silver nanocube pattern distribution based on the Brush-Mat method according to claim 1, characterized in that: The method also includes testing the adsorption performance of the patterned Mat material surface through an adsorption experiment: placing the prepared silver cube solution on the surface of the Mat material to observe whether adsorption occurs. If there is no adsorption within the specified time, it meets the requirements.

9. A metasurface material, characterized in that: The method is as described in any one of claims 1 to 8.

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