Functionalized glass for sers detection and method of making the same

Abstract

The application relates to a functionalized glass for SERS detection and a preparation method thereof, characterized by the following steps: a. tetraethyl orthosilicate and oxalic acid are mixed into a 0.02-0.10 moL / L sol in anhydrous ethanol according to a molar ratio of 1:2-5, a stabilizer with a volume of 5-50% is added, and then the mixture is stirred and transferred into a four-necked flask; b. after being heated and stirred for 12-16 hours, an anhydrous ethanol emulsion of polystyrene small balls with a mass fraction of 5-20% and a volume of 6-18% is added; c. an anhydrous ethanol solution of a surfactant P123 with a total mass of 2-8% and a weight concentration of 3-8% is added, and then the mixture is stirred and aged; d. a wet film is prepared on a glass substrate, and then the wet film is dried and kept warm; (2) a nano-silver particle dispersion liquid with a concentration of 5-25 mg / mL is prepared; and (3) the glass substrate prepared in the step d is coated with the nano-silver particle dispersion liquid and dried. The application has the advantages of simple process and low cost; the surface of the porous structure silica nano-particles has a large number of nanoscale gap structures, which is beneficial to obtaining an enhanced silver nano-particle surface plasmon resonance electromagnetic field, and greatly enhances the Raman signal of the adsorbed molecules.

Description

Technical Field

[0001] This invention belongs to the fields of materials engineering and nanotechnology, and relates to a functionalized glass for SERS detection and its preparation method. Background Technology

[0002] Raman spectroscopy is generally a convenient method for identifying the composition of substances. However, many chemical substances cannot be detected directly by Raman spectroscopy, requiring Raman enhancement techniques to improve the signal-to-noise ratio and thus detect the Raman signal of the analyte. In recent years, surface-enhanced Raman scattering (SERS) technology has been widely used in material detection under various conditions. The preparation of SERS-active matrix materials is crucial for achieving its excellent detection performance.

[0003] Silver nanomaterials are a promising candidate for SERS substrates due to their excellent biocompatibility, environmental stability, and high electromagnetic field enhancement efficiency. Furthermore, research has shown that introducing a rough, porous substrate can further improve the surface electromagnetic field excitation efficiency of noble metal nanomaterials, thus enhancing the detection sensitivity of SERS technology. In addition, the use of inexpensive, commercially available materials to prepare SERS matrix materials is currently a research hotspot in this field. To date, there are no publicly available research reports on the preparation of Raman substrates with excellent SERS activity by combining glass substrates with porous silica nanospheres and silver nanoparticles with excellent SERS activity. Summary of the Invention

[0004] The purpose of this invention is to overcome the shortcomings of the prior art and provide a functionalized glass for SERS detection and its preparation method, which can significantly enhance the Raman signal of adsorbed molecules.

[0005] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0006] A functionalized glass for SERS detection includes a glass substrate, characterized by having the following structure: porous silica nanoparticles coated with silver nanospheres on the glass substrate.

[0007] Furthermore, the diameter of the porous silica nanoparticles is 80–120 nm.

[0008] Furthermore, the diameter of the silver nanospheres is 20–40 nm.

[0009] A method for preparing functionalized glass for SERS detection, characterized by comprising the following steps:

[0010] (1) Preparation of porous silica nanoparticles:

[0011] a. Tetraethyl silicate (SiC8H) 20 O4) and analytical grade oxalic acid (C2H2O4) are dissolved in anhydrous ethanol at a molar ratio of 1:2 to 1:5. The mixture is stirred until all the raw materials are dissolved to prepare a SiO2 sol with a concentration of 0.02 to 0.10 mol / L. Then, 5 to 50% of the volume of the SiO2 sol is added as a stabilizer. After stirring for 20 to 30 minutes, the solution is transferred to a four-necked flask.

[0012] b. Place the four-necked flask in an oil bath at 100-120°C and heat and stir for 12-16 hours. Add an anhydrous ethanol emulsion containing polystyrene microspheres, wherein the mass percentage of the polystyrene microsphere emulsion is 5-20%, and control the amount of polystyrene microsphere emulsion added to be 6-18% of the total sol volume.

[0013] c. Continue to add 2-8% by weight of anhydrous ethanol solution of surfactant P123 (the mass concentration of surfactant P123 in anhydrous ethanol solution is 3-8%) to the four-necked flask, and continue stirring at room temperature until a uniform emulsion sol is formed, and let it stand for 8-24 hours.

[0014] d. Subsequently, a wet film (70-150 nm thick) of the aged sol was prepared on the glass substrate, dried in an oven at 100-150℃ for 10-30 min, and then kept at 450-650℃ for 20-30 min to obtain glass coated with porous silica nanoparticles.

[0015] (2) Preparation of silver nanosphere porous silica nanoparticle composite material: Add silver nanoparticles to the dispersant and stir thoroughly for 20-40 min to obtain silver nanoparticle dispersion, wherein the mass-volume ratio of silver nanoparticles to dispersant is 5-25 mg / mL and the diameter of silver nanoparticles is 20-40 nm.

[0016] (3) Preparation of functionalized glass: The silver nanoparticle dispersion obtained in step (2) is coated onto the glass substrate obtained in step (1) by spin coating and dried at room temperature to obtain functionalized glass loaded with silver nanosphere porous silica nanoparticle composite material for SERS detection.

[0017] Furthermore, the glass substrate is high-hardness display glass, microcrystalline glass, high-aluminum glass, ultra-thin flexible glass, etc.

[0018] Furthermore, the stabilizer is any one of n-propanol, monoethanolamine, diethanolamine, acetylacetone, N,N-dimethylformamide, and N,N-dimethylacetamide.

[0019] Furthermore, the methods for preparing the wet film mainly include spin coating, dip coating, blade coating, and roller coating.

[0020] Furthermore, the dispersant is mainly a mixture of one or more of anhydrous ethanol, isopropanol, and ethylene glycol methyl ether.

[0021] In this invention, polystyrene microspheres are used as the core, and a layer of silica solution is wrapped around them to form a spherical structure. The film is deposited on a glass substrate, and under high temperature firing, the polystyrene decomposes into organic matter, thus creating a hollow sphere structure. The size of the hollow spheres is at the nanometer level, that is, the porous silica nanoparticles.

[0022] Compared with the prior art, the advantages of the present invention are as follows:

[0023] 1. This invention uses glass as the substrate material and coats a composite material of silver nanospheres and porous silica nanoparticles onto the glass substrate, which is simple to manufacture and low in cost;

[0024] 2. The functionalized glass for SERS detection described in this invention has a simple composition and a large number of nanoscale gap structures on its surface, which is conducive to obtaining an enhanced surface plasmon resonance electromagnetic field of silver nanoparticles, greatly enhancing the Raman signal of adsorbed molecules; and the porous silica nanoparticles have a large surface area, which is conducive to the aggregation of silver nanoparticles and the adsorption of analyte molecules. Detailed Implementation

[0025] A method for preparing functionalized glass for SERS detection, the specific implementation steps of which are as follows:

[0026] Example 1

[0027] (1) Preparation of porous silica nanoparticles:

[0028] a. Add 30 mL of tetraethyl silicate (SiC8H) 20 24 g of analytical grade oxalic acid (C2H2O4) was dissolved in 300 mL of anhydrous ethanol and stirred until the raw materials were completely dissolved to prepare a SiO2 sol (SiC8H4O4) with a concentration of 0.04 mol / L. 20 The molar ratio of O4 to C2H2O4 is 1:2. Then, 3 mL of the stabilizer n-propanol is added, and the mixture is stirred for 20 min before being transferred to a four-necked flask.

[0029] b. Place the four-necked flask in a 100°C oil bath and heat and stir for 13 hours. Add 24 mL of anhydrous ethanol emulsion containing polystyrene microspheres, wherein the emulsion contains 6% polystyrene microspheres by mass.

[0030] c. Continue to add 30 mL of anhydrous ethanol solution of surfactant P123 with a mass fraction of 3% to the four-necked flask, and continue stirring at room temperature until a uniform emulsion sol is formed. Let it stand and age for 10 h.

[0031] d. Subsequently, a wet film (80 nm thick) of the aged sol was prepared on the glass substrate by spin coating, dried in an oven at 120 °C for 30 min, and then kept at 500 °C for 20 min to obtain glass coated with porous silica nanoparticles.

[0032] (2) Preparation of silver nanosphere porous silica nanoparticle composite material: 0.32g of silver nanoparticles with a diameter of 25nm were added to 30mL of dispersant (ethylene glycol methyl ether) and stirred for 25min to obtain a silver nanoparticle dispersion with a mass-volume ratio of 8mg / mL.

[0033] (3) Preparation of functionalized glass: The silver nanoparticle dispersion obtained in step (2) is coated onto the glass substrate obtained in step (1) by spin coating and dried at room temperature to obtain functionalized glass loaded with silver nanosphere porous silica nanoparticle composite material for SERS detection.

[0034] Example 2

[0035] (1) Preparation of porous silica nanoparticles:

[0036] a. Add 60 mL of tetraethyl silicate (SiC8H) 20 72g of analytical grade oxalic acid (C2H2O4) was dissolved in 300mL of anhydrous ethanol and stirred until the raw materials were completely dissolved to prepare a SiO2 sol (SiC8H4O4) with a concentration of 0.08mol / L. 20 The molar ratio of O4 to C2H2O4 is 1:2.5. Then, 7.5 mL of stabilizer (diethanolamine) is added, and the solution is stirred for 30 min before being transferred to a four-necked flask.

[0037] b. Place the four-necked flask in a 120°C oil bath and heat and stir for 14 hours. Add 36 mL of anhydrous ethanol emulsion containing polystyrene microspheres, wherein the mass percentage of the polystyrene microsphere emulsion is 15%.

[0038] c. Continue to add 20 mL of anhydrous ethanol solution of surfactant P123 with a mass fraction of 5% to the four-necked flask, and continue stirring at room temperature until a uniform emulsion sol is formed. Let it stand and age for 16 hours.

[0039] d. Subsequently, a wet film (100 nm thick) of the aged sol was prepared on the glass substrate by spin coating, dried in an oven at 130 °C for 20 min, and then kept at 600 °C for 25 min to obtain glass coated with porous silica nanoparticles.

[0040] (2) Preparation of silver nanosphere porous silica nanoparticle composite material: 0.48 g of silver nanoparticles with a diameter of 30 nm were added to 30 mL of dispersant (ethylene glycol methyl ether) and stirred for 30 min to obtain a silver nanoparticle dispersion with a mass-volume ratio of 12 mg / mL.

[0041] (3) Preparation of functionalized glass: The silver nanoparticle dispersion obtained in step (2) is coated onto the glass substrate obtained in step (1) by spin coating and dried at room temperature to obtain functionalized glass loaded with silver nanosphere porous silica nanoparticle composite material for SERS detection.

[0042] Example 3

[0043] (1) Preparation of porous silica nanoparticles:

[0044] a. Add 75 mL of tetraethyl silicate (SiC8H) 20 Dissolve 84g of analytical grade oxalic acid (C2H2O4) in 300mL of anhydrous ethanol and stir until the raw materials are completely dissolved to prepare a 0.1mol / L SiO2 sol (SiC8H2O4). 20 The molar ratio of O4 to C2H2O4 is 1:5. Then, 15 mL of stabilizer (N,N-dimethylformamide) is added, and the solution is stirred for 30 min before being transferred to a four-necked flask.

[0045] b. Place the four-necked flask in a 120°C oil bath and heat and stir for 15 hours. Add 36 mL of anhydrous ethanol emulsion containing polystyrene microspheres, wherein the emulsion contains 20% polystyrene microspheres by mass.

[0046] c. Continue to add 15 mL of anhydrous ethanol solution of surfactant P123 with a mass fraction of 7.5% to the four-necked flask, and continue stirring at room temperature until a uniform emulsion sol is formed. Let it stand and age for 10 h.

[0047] d. Subsequently, a wet film (130 nm thick) of the aged sol was prepared on the glass substrate by spin coating, dried in an oven at 150 °C for 15 min, and then kept at 650 °C for 20 min to obtain glass coated with porous silica nanoparticles.

[0048] (2) Preparation of silver nanosphere porous silica nanoparticle composite material: 0.96g of silver nanoparticles with a diameter of 35nm were added to 30mL of dispersant (ethylene glycol methyl ether) and stirred for 40min to obtain a silver nanoparticle dispersion with a mass-volume ratio of 24mg / mL.

[0049] (3) Preparation of functionalized glass: The silver nanoparticle dispersion obtained in step (2) is coated onto the glass substrate obtained in step (1) by spin coating and dried at room temperature to obtain functionalized glass loaded with silver nanosphere porous silica nanoparticle composite material for SERS detection.

Claims

1. A method for the preparation of functionalized glass for SERS detection, comprising a glass substrate, characterized in that A porous silica nanoparticle coated with silver nanospheres on a glass substrate, having the following structure: The method comprises the following steps: (1) Preparation of the porous silica nanoparticle: a. Tetraethyl silicate (SiC8H 20 O4) and analytical pure oxalic acid (C2H2O4) were mixed in anhydrous ethanol at a molar ratio of 1:2-1:5, and stirred until all raw materials were dissolved, to prepare SiO2 sol with a concentration of 0.02-0.10 moL / L. Then, 5-50% of the volume of the SiO2 sol was added as a stabilizer, and the solution was transferred into a four-necked flask after stirring for 20-30 min. b. Place the four-necked flask in an oil bath heated at 100-120 °C and stir for 12-16 h. Add the polystyrene ball emulsion in anhydrous ethanol, wherein the mass percentage of the polystyrene ball emulsion is 5-20%, and the amount of the polystyrene ball emulsion added is 6-18% of the total sol volume; c. Continue to add 2-8% of the mixed solution of a 3-8% weight concentration of surfactant P123 in anhydrous ethanol to the four-necked flask, and continue to stir at room temperature until a uniform emulsion sol is formed. Let it stand for 8-24 h; d. Then prepare a wet film of the aged sol on a glass substrate, dry it in an oven at 100-150 °C for 10-30 min, and then heat it at 450-650 °C for 20-30 min to obtain the glass coated with porous silica nanoparticles; (2) Preparation of the silver nanosphere porous silica nanoparticle composite material: Add the silver nanoparticles to the dispersant and stir thoroughly for 20-40 min to obtain a silver nanoparticle dispersion, wherein the mass volume ratio of the silver nanoparticles to the dispersant is 5-25 mg / mL, and the diameter of the silver nanoparticles is 20-40 nm; (3) Preparation of the functionalized glass: Apply the silver nanoparticle dispersion prepared in step (2) to the glass substrate prepared in step (1) by spin coating, and dry it at room temperature to obtain the functionalized glass loaded with the silver nanosphere porous silica nanoparticle composite material for SERS detection. 2.The method for preparing functionalized glass for SERS detection according to claim 1, characterized in that: The diameter of the porous silica nanoparticles is 80-120 nm.

3. The method for preparing functionalized glass for SERS detection according to claim 1, characterized in that: The diameter of the silver nanospheres is 20-40 nm.

4. The method for preparing functionalized glass for SERS detection according to claim 1, characterized in that: The glass substrate is high-hardness display glass, microcrystalline glass, high-aluminum glass, or ultra-thin flexible glass.

5. The method for preparing functionalized glass for SERS detection according to claim 1, characterized in that: The stabilizer is any one of n-propanol, monoethanolamine, diethanolamine, acetylacetone, N,N-dimethylformamide, or N,N-dimethylacetamide.

6. The method of claim 1, wherein the functionalized glass for SERS detection is prepared by the steps of: The method for preparing the wet film mainly includes spin coating, pulling, scraping, and rolling.

7. The method for preparing functionalized glass for SERS detection according to claim 1, characterized in that: The thickness of the wet film is 70-150 nm.

8. A method for preparing functionalized glass for SERS detection according to any one of claims 1-7, characterized in that: The dispersant is mainly a mixture of one or more of anhydrous ethanol, isopropanol, and ethylene glycol methyl ether.