Surface enhanced Raman scattering substrate and preparation method thereof

Abstract

The invention discloses a surface-enhanced Raman scattering substrate and a preparation method thereof, and belongs to the technical field of Raman spectrums.The preparation method comprises the steps that PET fabric is sequentially subjected to ultrasonic cleaning in absolute ethyl alcohol and deionized water for 10 min and then placed in a 70 DEG C drying oven to be dried, the PET fabric is soaked in PDMS for 1 min and then taken out, then the PET fabric is placed on filter paper, redundant PDMS is leached out, and a PDMS coating is obtained; a PDMS coating is treated for 20 min through Ar plasma by using a plasma cleaning machine, a PDMS / PET substrate with a micro-wrinkle structure on the surface is obtained, Ag nanoparticles are deposited on the surface of the PDMS / PET substrate by using an evaporation coating system, a super-hydrophobic Ag / PDMS / PET substrate is obtained, and a three-dimensional micron-sized structure is constructed by using PET fabric and the micro-wrinkle PDMS coating. A micro-nano multi-level structure is formed by the nano-silver particles and the Ag nano-particles on the surface, so that the substrate is super-hydrophobic.

Description

Technical Field

[0001] The present invention belongs to the technical field of Raman spectroscopy, and in particular relates to a surface enhanced Raman scattering substrate and a preparation method thereof. Background Art

[0002] Surface-enhanced Raman scattering (SERS) is a powerful spectroscopic analysis technique. Its specific recognition of target molecules and extremely low detection limits give it broad application prospects in the detection of trace substances. The sensitivity of SERS technology depends primarily on the enhancement capability of the SERS substrate. Therefore, SERS substrates with low preparation costs, simple processes, and high enhancement factors are of great importance for research.

[0003] Traditional SERS substrates are usually processed on materials such as silicon or glass. Many traditional substrates require specific microstructures, resulting in high production costs and strict requirements on subsequent processing equipment and environment, which makes the templates expensive and difficult to preserve or reuse. The PET fabric template used in this patent is a common fabric on the market, which has the advantages of being safe, cheap, stable and easy to preserve. When the SERS substrate is used for liquid pollutant detection, it is usually necessary to drop the liquid to be tested onto the surface of the substrate. For SERS substrates that are not hydrophobic, the droplets will spread on the surface of the substrate and contact the surface over a large area, resulting in insufficient concentration of the probe molecules on the surface of the substrate, which is not conducive to the detection of low-concentration analytes. The SERS substrate with a super-hydrophobic surface used in the present invention effectively solves this problem. In addition, in actual applications, most SERS substrates are difficult to clean and reuse after use, while the SERS substrate proposed in this patent can be easily cleaned and reused due to its flexible fabric characteristics, thereby effectively saving consumption costs. Summary of the Invention

[0004] Technical issues solved:

[0005] In order to address the shortcomings of the prior art, such as high cost, complex process and low reusability, the present application provides a surface-enhanced Raman scattering substrate and a preparation method thereof.

[0006] Technical solution:

[0007] To achieve the above objectives, this application is implemented through the following technical solutions:

[0008] A method for preparing a surface-enhanced Raman scattering substrate, comprising the following steps:

[0009] The first step is to clean the PET fabric: the PET fabric is ultrasonically cleaned in anhydrous ethanol and deionized water for 10 min at an ultrasonic frequency of 40 kHz, and then dried in an oven at 70 °C for 30 min.

[0010] The second step is to coat the PET fabric with PDMS: the PET fabric is soaked in the PDMS solution for 1 minute, then taken out and placed on filter paper to drain the excess PDMS to obtain a PDMS coating.

[0011] The third step is to treat the PDMS coating with Ar plasma: the PDMS coating is treated with Ar plasma using a plasma cleaning machine for 20 minutes to obtain a PDMS / PET substrate with a micro-wrinkled surface structure;

[0012] The fourth step is to deposit Ag nanoparticles on the surface of the PDMS / PET substrate: Ag nanoparticles are deposited on the surface of the PDMS / PET substrate using an evaporation coating system to obtain a superhydrophobic Ag / PDMS / PET substrate, namely a surface-enhanced Raman scattering substrate.

[0013] Furthermore, the PET fabric in the first step is a PET fabric with a single fiber diameter of 0.01 mm.

[0014] Furthermore, the PDMS in the second step is a PDMS prepolymer with a model number of MW770.

[0015] Furthermore, the Ag nanoparticles in the fourth step are silver particles with a purity of ≥99.99%.

[0016] Furthermore, the plasma cleaning machine in the third step is SAT-5D.

[0017] Furthermore, during the treatment in the third step, the power is set to 150W, the air pressure in the cavity is 30Pa, and the air intake speed is 0.5L / min.

[0018] Furthermore, the evaporation coating system in the fourth step is JSD-300.

[0019] Furthermore, during the deposition process in the fourth step, the pressure in the evaporation coating system chamber is 8×10 -4 Pa, the deposition rate is 0.05 nm / s, and the deposition time is 30 min.

[0020] The present application also discloses a surface-enhanced Raman scattering substrate prepared by any of the above preparation methods.

[0021] Principle explanation: A polydimethylsiloxane (PDMS) layer is wrapped on the fiber surface of polyester fiber (PET) fabric, and a wrinkled structure is formed on its surface through plasma treatment to prepare a highly sensitive and uniform super-hydrophobic surface-enhanced Raman scattering (SERS) substrate for trace detection of target molecules. The present invention uses PET fabric as a template, first coating PDMS on the surface of the PET fabric, and then inducing gradient cross-linking of the PDMS coating through Ar plasma treatment, thereby forming a micron-scale wrinkled structure. Finally, Ag nanoparticles are further deposited on the structure through evaporation coating technology to introduce SERS "hot spots", and at the same time, together with the micro-wrinkled structure of the substrate, a micro-nano secondary roughness is formed to obtain a highly sensitive SERS substrate with super-hydrophobicity. The substrate has good hydrophobicity and high sensitivity, can realize low-concentration detection of target molecules, and has low preparation cost, low consumption, and simple process. In addition, the SERS substrate is reusable, economical and environmentally friendly.

[0022] Beneficial effects:

[0023] This application provides a surface-enhanced Raman scattering substrate and a preparation method thereof, which has the following advantages compared with the prior art:

[0024] 1. In the SERS substrate of this patent invention, a three-dimensional micron-scale structure is constructed using PET fabric and a micro-corrugated PDMS coating. Combined with evaporation coating technology, a large number of SERS "hotspots" are introduced, while Ag nanoparticles and the PDMS / PET substrate together form a micro-nano multi-level structure.

[0025] 2. The periodic structure of PDMS wrinkles ensures the uniformity of the surface-enhanced Raman scattering substrate. The large number of "hot spots" and three-dimensional structure ensure the high sensitivity of the substrate. The micro-nano multi-level structure provides the substrate with superhydrophobicity.

[0026] 3. The surface-enhanced Raman scattering substrate prepared in this application is low-cost, economical and environmentally friendly;

[0027] 4. The preparation process of surface-enhanced Raman scattering substrate is simple and does not require expensive instruments and equipment;

[0028] 5. The superhydrophobicity of the Ag / PDMS / PET substrate enables it to be used for low-concentration trace detection, overcoming the shortcomings of traditional SERS substrates, which are complex and costly to fabricate and have insufficient enrichment capacity for target molecules.

[0029] 6. While the Ag / PDMS / PET substrate exhibits high enhancement performance, its reusability is significantly improved compared to other SERS substrates. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1Figure 1 is a flow chart of the preparation of the Ag / PDMS / PET SERS substrate of the present application, wherein (a) shows the coating of PDMS on the surface of PET fabric, (b) shows the treatment of the PDMS coating with Ar plasma, and (c) shows the deposition of Ag nanoparticles on the surface of the PDMS / PET substrate.

[0031] Figure 2 This is a SEM image of the surface structure of the PET fabric of the present application;

[0032] Figure 3 is a SEM image of the PDMS / PET substrate after Ar plasma treatment in this application;

[0033] Figure 4 is a SEM image of Ag nanoparticles on the surface of the Ag / PDMS / PET substrate of the present application;

[0034] Figure 5 Fourier transform infrared spectra of the PET fabric and PDMS / PET substrate of this application;

[0035] Figure 6 This is the static contact angle diagram of the Ag / PDMS / PET substrate of this application;

[0036] Figure 7 Raman spectra of different concentrations of crystal violet on Ag / PDMS / PET substrate of this application;

[0037] Figure 8 For this application, the SERS substrate 10 -8 mol / L crystal violet and 10 on silicon wafer -1 Raman spectrum of mol / L crystal violet;

[0038] Figure 9 This is the SERS signal diagram of the SERS substrate that can still effectively capture malachite green after 10 cleaning-detection cycles, where (a) is the SERS signal of 10 -8 mol / L malachite green Raman spectrum, (b) is the SERS substrate measured 10 -8 Graph showing the changes in the intensity of the characteristic peaks of mol / L malachite green. DETAILED DESCRIPTION

[0039] In order to make the purpose, technical solutions and advantages of the present invention clearer, the present invention will be further described in detail in conjunction with specific embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and should not be used to limit the scope of protection of the present invention.

[0040] The plasma cleaning machine used in this application is SAT-5D; the evaporation coating system is JSD-300.

[0041] Example 1

[0042] like Figure 1 As shown, a method for preparing a surface enhanced Raman scattering substrate comprises the following specific steps:

[0043] The first step is to clean the PET fabric: the PET fabric is cleaned in anhydrous ethanol and deionized water at 40 kHz for 10 min, and then dried in a 70°C oven for 30 min. The PET fabric is a PET fabric with a single fiber diameter of 0.01 mm.

[0044] The second step is to coat PDMS on the surface of the PET fabric: soak the PET fabric in PDMS for 1 min, take it out, and then place it on filter paper to drain out excess PDMS to obtain a PDMS coating, such as Figure 1 As shown in (a), PDMS is a PDMS prepolymer with a model number of MW770;

[0045] The third step is to treat the PDMS coating with Ar plasma: the PDMS coating is treated with Ar plasma using a plasma cleaning machine for 20 minutes to obtain a PDMS / PET substrate with a micro-wrinkled surface structure, such as Figure 1 As shown in (b), during the treatment process, the power was set to 150 W, the pressure in the chamber was 30 Pa, and the air inlet speed was 0.5 L / min;

[0046] The fourth step is to deposit Ag nanoparticles on the surface of PDMS / PET substrate: Ag nanoparticles are deposited on the surface of PDMS / PET substrate using an evaporation coating system to obtain a super-hydrophobic Ag / PDMS / PET substrate, i.e., a surface-enhanced Raman scattering substrate. Figure 1 As shown in (c), the Ag nanoparticles are silver particles with a purity of ≥99.99%. During the deposition process, the pressure in the evaporation coating system chamber is 8×10 -4 Pa, the deposition rate is 0.05 nm / s, and the deposition time is 30 min.

[0047] Figure 2 This is a SEM image of the cleaned PET fabric raw material used in this patent.

[0048] Figure 3 This is the surface morphology of the PDMS / PET substrate after Ar plasma treatment.

[0049] Figure 4 It is the SEM image of the Ag / PDMS / PET substrate surface obtained after depositing Ag nanoparticles on the PDMS / PET substrate surface.

[0050] Figure 5The FTIR spectra of the PET fabric and PDMS / PET substrate were collected using a Nicolet IS10 Fourier transform infrared spectrometer. The characteristic peaks from PDMS are marked in the figure, confirming the successful coating of PDMS on the PET substrate surface.

[0051] Figure 6 This is the static contact angle of 25 μL of water on the Ag / PDMS / PET substrate, measured using a contact angle meter (Dataphysics OCA20, Germany). The substrate exhibits a static contact angle of 161.2 ± 1.7°, demonstrating superhydrophobicity.

[0052] Figure 7 The Raman spectrum was measured on the surface of the prepared Ag / PDMS / PET substrate using crystal violet as the probe molecule. The minimum detection concentration of this substrate can reach 10 -9 mol / L.

[0053] like Figure 8 As shown, by EF=(I SERS *C 0) / (I0*C SERS ) calculated that the enhancement factor of the SERS substrate prepared by the solution of this patent invention can reach 3.28×10 8 .

[0054] like Figure 9 As shown, after 10 cleaning-detection cycles, the SERS substrate prepared by the solution of this patent invention can still effectively capture the SERS signal of malachite green, and its signal attenuation rate is less than 30%.

[0055] The Ag / PDMS / PET substrate in this application not only exhibits high enhancement performance, but also has significantly improved reusability compared to other SERS substrates, as shown in the following table:

[0056]

[0057] [1]Samriti,Kumar P,Kuznetsov AY,et al.Sensitive,stable,andrecyclable ZnO / Ag nanohybrid substrates for surface-enhanced Raman scatteringmetrology[J].ACS Materials Au,2024,4(4):413-423.

[0058] [2]Peng S, Wang

[0059] [3]Zheng Y, Yin L, Jayan H, et al. In situ self-cleaning PAN / Cu2O@Ag / Au@Ag flexible SERS sensor coupled with chemometrics for quantitative detection of thiram residues on apples[J]. Food Chemistry, 2025,473:143032.

[0060] [4]Wang J, Liu D, Yu N, et al. Low-cost Ag / ZnO nanosheets arrays assensitive and recyclable surface-enhanced Raman scattering substrates[J]. Optical Materials, 2024,157:116187.

[0061] The examples selected in the above materials are intended to facilitate understanding and are not intended to limit the process. Those skilled in the art may readily modify the process or transfer it to other cases without inventive change. If such modifications fall within the same scope of claims or similar technologies as the present invention, the invention is intended to encompass such modifications.

Claims

1. A method for preparing a surface-enhanced Raman scattering substrate, characterized in that: The specific steps are: The first step is to clean the PET fabric: the PET fabric is ultrasonically cleaned in anhydrous ethanol and deionized water for 10 min at an ultrasonic frequency of 40 kHz, and then dried in an oven at 70 °C for 30 min. The second step is to coat the PET fabric with PDMS: the PET fabric is soaked in the PDMS solution for 1 minute, then taken out and placed on filter paper to drain the excess PDMS to obtain a PDMS coating. The third step is to treat the PDMS coating with Ar plasma: the PDMS coating is treated with Ar plasma using a plasma cleaning machine for 20 minutes to obtain a PDMS / PET substrate with a micro-wrinkled surface structure; The fourth step is to deposit Ag nanoparticles on the surface of the PDMS / PET substrate: Ag nanoparticles are deposited on the surface of the PDMS / PET substrate using an evaporation coating system to obtain a superhydrophobic Ag / PDMS / PET substrate, namely a surface-enhanced Raman scattering substrate.

2. The method for preparing a surface-enhanced Raman scattering substrate according to claim 1, characterized in that: The PET fabric in the first step is a PET fabric with a single fiber diameter of 0.01 mm.

3. The method for preparing a surface-enhanced Raman scattering substrate according to claim 1, wherein: The PDMS in the second step is a PDMS prepolymer with a model of MW770.

4. The method for preparing a surface-enhanced Raman scattering substrate according to claim 1, wherein: In the fourth step, the Ag nanoparticles are silver particles with a purity of ≥99.99%.

5. The method for preparing a surface-enhanced Raman scattering substrate according to claim 1, wherein: The plasma cleaning machine in the third step is SAT-5D.

6. The method for preparing a surface-enhanced Raman scattering substrate according to claim 1, wherein: During the treatment process in the third step, the power is set to 150W, the air pressure in the cavity is 30Pa, and the air intake speed is 0.5L / min.

7. The method for preparing a surface-enhanced Raman scattering substrate according to claim 1, characterized in that: The evaporation coating system in the fourth step is JSD-300.

8. The method for preparing a surface-enhanced Raman scattering substrate according to claim 1, wherein: During the deposition process in the fourth step, the pressure in the evaporation coating system chamber is 8×10 -4 Pa, the deposition rate is 0.05 nm / s, and the deposition time is 30 min.

9. A surface-enhanced Raman scattering substrate prepared by the preparation method according to any one of claims 1 to 8.

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