CN106525808B - Preparation method of flexible surface-enhanced Raman substrate based on polymer - Google Patents

Abstract

The invention relates to the technical field of Raman detection, and provides a method for preparing a flexible surface-enhanced Raman substrate using a polymer as a substrate, including: 1. preparing a polymer film doped with a reducing agent; 2. configuring a polymer film containing silver 3. Add the polymer film prepared in 1 to the solution prepared in 2 to modify the surface of the silver particles; take it out and dry it to obtain a flexible surface reinforced pulley. Mandi. The beneficial effects of the present invention are: through the combination of the polymer and the reducing agent, the polymer that does not have reducing properties can be used as a substrate for surface-enhanced Raman, and the metal layer on the surface of the polymer is obtained through the action of the reducing agent to form a polymer It is the metal nanostructure of the substrate, and this process plus additives are used to control the structure to obtain a surface-enhanced Raman substrate with excellent performance; the preparation method is simple, and the prepared surface-enhanced Raman substrate has high sensitivity and good repeatability.

Description

Preparation method of flexible surface-enhanced Raman substrate based on polymer

technical field

The invention relates to the technical field of Raman detection, in particular to a method for preparing a flexible surface-enhanced Raman substrate with a polymer as a substrate.

Background technique

Surface-enhanced Raman scattering has the characteristics of high sensitivity, low detection limit and providing molecular fingerprint signals, so it is widely used in the detection of pesticides, pollutants, additives and other chemical substances. The following conditions are required to generate surface-enhanced Raman signals: usually only a few metal surfaces can generate signals, and the effect of gold or silver is the best; metals need to have nanoscale surface structures and be relatively close to each other, so that Only enough hot spots are generated; the molecules to be tested can sufficiently contact the hot spot regions of these metals. From a practical point of view, in order to achieve the detection of chemical substances, in addition to high sensitivity and high repeatability, the difficulty of the preparation method of the substrate is also an important point to be considered.

Most surface-enhanced Raman substrates use silicon wafers or glass wafers as substrates, on which metal nanoparticles are controlled to assemble. Many preparation methods often involve liquid-phase solvent chemistry and surface chemistry for the regulation of the morphology and composition of metal nanoparticles. , high control precision, additional self-assembly of particles, controllable deposition or film formation operations are required, the process steps are complex, and the requirements for parameter control are high. Therefore, it is urgent to develop an efficient, flexible, low-cost, high-sensitivity, repeatable, uniform and stable preparation method for flexible surface-enhanced Raman scattering substrates. In recent years, polymer materials have attracted a lot of attention as substrates. Compared with traditional substrates, flexible substrates have the advantages of lightness, diversity, and easy tailoring. The surface-enhanced Raman substrate with a polymer as a substrate has great development potential as a flexible substrate. It is also well known that silver ions are reduced by reducing agents, but the present invention uses the combination of polymers and reducing agents, and the addition of additives. The simple method of reducing silver ions on the polymer surface leads to excellent substrates.

How to realize the effective combination of polymer and metal particles has always been a difficult point. The basic idea is through physical combination. One method is to directly reduce metal ions by using a polymer with a certain reducibility, but there are relatively few types of such polymers; the other method is to use ion sputtering, ion etching, etc. The method of etching or deposition combines the metal with the polymer in a physical combination. This method often requires high equipment requirements, is expensive, and has complicated processes.

In the invention patent CN104849259A, before depositing gold and silver nanoparticles on the surface of the flexible substrate, the flexible substrate is subjected to surface hydrophilic treatment and silanization treatment in sequence, and gold and silver nanoparticles are deposited to obtain a polymer surface-enhanced Raman substrate. The technical solution disclosed in this patent not only keeps the production cost of the surface-enhanced Raman substrate high, but also complicates the preparation process.

Contents of the invention

The purpose of the present invention is to overcome the deficiencies of the prior art, to provide a method for preparing a flexible surface-enhanced Raman substrate with a polymer as a substrate, which solves the shortcomings of the above-mentioned methods well, and makes itself non-reducible Polymers can be used as substrates for surface-enhanced Raman. The metal layer on the surface of the polymer is obtained through the action of a reducing agent to form a metal nanostructure with the polymer as the substrate. This process can be adjusted by adding additives to achieve performance. Excellent surface-enhanced Raman substrate.

A method for preparing a flexible surface-enhanced Raman substrate with a polymer as a substrate of the present invention comprises the following steps:

Step 1, preparing a polymer film doped with a reducing agent; adding polymer powder and a reducing agent to the solvent, mixing uniformly, and volatilizing the solvent to prepare a polymer film doped with a reducing agent;

Step 2, configure a solution containing silver ions, and add a certain amount of protonic acid or surfactant in the solution;

Step 3, adding the reducing agent-doped polymer film prepared in step 1 to the solution prepared in step 2 to modify the surface of silver particles; take it out and dry it to obtain the flexible surface-enhanced Raman base.

Further, the contents of the polymer powder and the reducing agent added to the solvent in step 1 are 1wt%-50wt% and 0.1wt%-20wt%, respectively.

Further, the solvent in step one is water, methanol, ethanol, acetonitrile, n-hexane, n-octane, benzene, toluene, xylene, sulfoxide, dimethylimine, diethylimine one, or a mixture of several components.

Further, the polymer in step one is polyethylene, polypropylene, polystyrene, polybutadiene, polycarbonate, polymethyl methacrylate, polydimethylsiloxane, polypyrrole, poly One of thiophene, polyaniline, polyacrylonitrile, polyamide, or a mixture of several components.

Further, the reducing agent in step 1 is one of sodium borohydride, sodium bisulfite, formaldehyde solution, paraformaldehyde, fructose, galactose, glucose, sodium citrate, or a mixture of several components.

Further, the preparation temperature of the reducing agent-doped polymer film in step 1 is 20°C-200°C, and the preparation time is 1-24 hours.

Further, the solution containing silver ions in step 2 is silver nitrate solution or silver ammonia solution.

Further, the protonic acid in step 2 is one of malic acid, phosphoric acid, p-toluenesulfonic acid, succinic acid, lactic acid, or a mixture of several compositions; the surfactant is twelve Sodium Alkylbenzene Sulfonate, Sodium Lauryl Sulfonate, Cetyl Trimethyl Ammonium Bromide, Cetyl Trimethyl Ammonium Chloride, Lauryl Mercaptan, Polyvinylpyrrolidone, Stearic Acid, One of lecithin, fatty acid glycerides, polysorbate, oleic acid, lauric acid, or a mixture of several components.

Further, when configuring the solution containing silver ions in step 2, when adding protonic acid in the solution, the concentration of protonic acid is 0.1wt%-5wt%; when adding surfactant in the solution, the surface The concentration of the active agent is 0.1wt%-5wt%.

Further, the time for surface modification of the silver particles in step three is 10 minutes to 5 hours.

The beneficial effects of the present invention are: through the combination of the polymer and the reducing agent, the polymer that does not have reducing properties can be used as a substrate for surface-enhanced Raman, and the metal layer on the surface of the polymer is obtained through the action of the reducing agent to form a polymer It is the metal nanostructure of the substrate, and this process plus additives are used to control the structure to obtain a surface-enhanced Raman substrate with excellent performance; the preparation method is simple, and the prepared surface-enhanced Raman substrate has high sensitivity and good repeatability.

Description of drawings

FIG. 1 is a flowchart of a method for preparing a flexible surface-enhanced Raman substrate using a polymer as a substrate according to Example 1 of the present invention.

FIG. 2 shows the topography of the polyacrylonitrile film surface modified with silver nanoparticles in Example 1 by a scanning electron microscope.

Fig. 3 shows the topography of the scanning electron microscope after the surface of the polyacrylonitrile film is modified with silver nanoparticles in Example 2.

Fig. 4 shows the Raman graphs of rhodamine 6G solutions with different concentrations performed on the surface-enhanced Raman substrate in Example 2.

Fig. 5 is a graph showing the repeatability detection of the surface-enhanced Raman substrate in Example 2 (10 points are randomly selected).

Detailed ways

Specific embodiments of the present invention will be described in detail below in conjunction with specific drawings. It should be noted that the technical features or combinations of technical features described in the following embodiments should not be regarded as isolated, and they can be combined with each other to achieve better technical effects. In the drawings of the following embodiments, the same reference numerals appearing in each drawing represent the same features or components, which can be applied in different embodiments.

In an embodiment of the present invention, a method for preparing a flexible surface-enhanced Raman substrate using a polymer as a substrate includes the following steps:

Step 1, preparing a polymer film doped with a reducing agent; adding polymer powder and a reducing agent to the solvent, mixing uniformly, and volatilizing the solvent to prepare a polymer film doped with a reducing agent;

Step 2, configure a solution containing silver ions, and add a certain amount of protonic acid or surfactant in the solution;

Step 3, adding the reducing agent-doped polymer film prepared in step 1 to the solution prepared in step 2 to modify the surface of silver particles; take it out and dry it to obtain the flexible surface-enhanced Raman base.

Wherein, the contents of the polymer powder and the reducing agent added in the solvent in step 1 are 1wt%-50wt% and 0.1wt%-20wt% respectively; the solvent is water, methanol, ethanol, acetonitrile, n-hexane alkane, n-octane, benzene, toluene, xylene, disulfoxide, dimethylimine, diethylimine, or a mixture of several compositions; the polymer is polyethylene, poly One of acrylic, polystyrene, polybutadiene, polycarbonate, polymethyl methacrylate, polydimethylsiloxane, polypyrrole, polythiophene, polyaniline, polyacrylonitrile, polyamide, or a mixture of several compositions; the reducing agent is one of sodium borohydride, sodium bisulfite, formaldehyde solution, paraformaldehyde, fructose, galactose, glucose, sodium citrate, or a mixture of several compositions.

Preferably, the preparation temperature of the reducing agent-doped polymer film in step 1 is 20°C-200°C, and the preparation time is 1-24 hours.

The solution containing silver ions in step 2 is silver nitrate solution or silver ammonia solution; the protonic acid is one of malic acid, phosphoric acid, p-toluenesulfonic acid, succinic acid, lactic acid, or several The mixture of composition; The surfactant is sodium dodecylbenzenesulfonate, sodium dodecylsulfonate, cetyltrimethylammonium bromide, cetyltrimethylammonium chloride, One of lauryl mercaptan, polyvinylpyrrolidone, stearic acid, lecithin, fatty acid glycerides, polysorbate, oleic acid, lauric acid, or a mixture of several components.

Preferably, when configuring the solution containing silver ions in step 2, when protic acid is added in the solution, the concentration of protonic acid is 0.1wt%-5wt%; when surfactant is added in the solution, the surface The concentration of the active agent is 0.1wt%-5wt%.

Preferably, the time for surface modification of the silver particles in step 3 is 10 minutes to 5 hours.

Example 1

A method for preparing a surface-enhanced Raman substrate using a polymer as a substrate in this embodiment, the preparation process is shown in Figure 1, and includes the following steps in sequence:

a. Weigh 0.3g of glucose powder and dissolve it in a certain amount of dimethylimine solution. After it is completely dissolved, weigh 0.8g of polyacrylonitrile powder and add it to the above solution, and continue to stir for 3 hours;

b. Pour the solution obtained in step a into the film-making box. The thickness of the film needs to be kept uniform. Let the solvent evaporate at room temperature, take it out of the film-making box after 24 hours, and set aside;

c. Take 0.85g of silver nitrate, dissolve it in 50mL of deionized water, add ammonia water to it, the solution turns from clear to cloudy, continue to add dropwise until the solution becomes clear again, stop the dropwise addition, and obtain silver ammonia solution, and the solution is constant to 0.1M;

d. Take 2 mL of silver ammonia solution, and add 0.2 mL of polyvinylpyrrolidone with a mass fraction of 1% to it.

e. Put the polymer film prepared in step b into the solution obtained in step d, and take it out after one hour;

f. Rinse the film surface with deionized water and let it dry. The morphology of the scanning electron microscope is shown in Figure 2, and the silver particles evenly cover the surface of the polymer;

Example 2

A method for preparing a surface-enhanced Raman substrate using a polymer as a substrate in this embodiment, the specific implementation steps are as follows:

a. Weigh 0.3g of glucose powder and dissolve it in a certain amount of dimethylimine solution. After it is completely dissolved, weigh 0.8g of polyacrylonitrile powder and add it to the above solution, and continue to stir for 3 hours;

b. Pour the solution obtained in step a into the film-making box. The thickness of the film needs to be kept uniform. Let the solvent evaporate at room temperature, take it out of the film-making box after 24 hours, and set aside;

c. Weigh 0.85g of silver nitrate, dissolve it in 50mL of deionized water, add ammonia water to it, the solution changes from clear to cloudy, continue to drop until the solution becomes clear again, stop the drop to obtain silver ammonia solution, and make the solution to volume to 0.1M;

d, take 2mL of silver ammonia solution, add 0.2mL of dodecyltrimethylammonium bromide with a mass fraction of 1%;

e. Put the polymer film prepared in step b into the solution obtained in step d, and take it out after 1 hour;

f, rinse the film surface with deionized water, dry, and its scanning electron microscope morphology is as shown in Figure 3, and the silver particles evenly cover the polymer surface;

g. Prepare 10 ^-7 M, 10 ^-8 M, 10 ^-9 M rhodamine 6G solutions;

h. Cut the surface-enhanced Raman substrate prepared in step f into small pieces and put them into rhodamine 6G solutions with different concentrations, take them out after 2 hours, and dry them in the air;

Raman test parameters are as follows: 514nm excitation light source, 50x telephoto lens, confocal aperture size 10μm, 1800 grating, 10s acquisition time. Figure 4 is the Raman diagram of different concentrations of rhodamine 6G solutions carried out on the surface-enhanced Raman substrate. It can be seen from the figure that the substrate can clearly detect the characteristic peak of rhodamine 6G, and the detection limit is low; Figure 5 It is a repeatability test for the surface-enhanced Raman substrate. 10 points are randomly selected. It can be seen from Figure 5 that the signal intensity of each point is not much different, and the surface material has good repeatability.

The beneficial effects of the present invention are: through the combination of the polymer and the reducing agent, the polymer that does not have reducing properties can be used as a surface-enhanced Raman substrate without ion sputtering or deposition, and through the action of the reducing agent The metal layer on the surface of the polymer is obtained, and the metal nanostructure with the polymer as the substrate is formed. This process plus additives for structure regulation has obtained a surface-enhanced Raman substrate with excellent performance; the preparation method is simple, and the prepared surface-enhanced Raman The substrate has high sensitivity and good repeatability.

Although several embodiments of the present invention have been given herein, those skilled in the art should understand that the embodiments herein can be changed without departing from the spirit of the present invention. The above-mentioned embodiments are only exemplary, and the embodiments herein should not be used as limitations on the scope of rights of the present invention.

Claims (5)

1. enhancing the preparation method of Raman substrate using polymer as the flexible surface of substrate, which comprises the following steps:

Step 1: preparation has the thin polymer film of reducing agent doping: polymer powder and reducing agent, mixing being added in a solvent The thin polymer film with reducing agent doping is made in solvent flashing after uniformly；The polymer is polyacrylonitrile；The reducing agent For one of sodium borohydride, sodium hydrogensulfite, formalin, paraformaldehyde, fructose, galactolipin, glucose, sodium citrate, Or the mixture of several compositions；

Step 2: solution of the configuration containing silver ion, is added a certain amount of Bronsted acid or surfactant in the solution；Institute Stating the solution containing silver ion is silver nitrate solution or silver ammino solution；The Bronsted acid is malic acid, phosphoric acid, to methylbenzene sulphur The mixture of one of acid, succinic acid, lactic acid or several compositions；The surfactant be neopelex, Dodecyl sodium sulfate, cetyl trimethylammonium bromide, hexadecyltrimethylammonium chloride, lauryl mercaptan, polyvinyl pyrrole The mixing of one of alkanone, stearic acid, lecithin, fatty glyceride, polysorbate, oleic acid, moon silicic acid or several compositions Object；

Step 3: the thin polymer film with reducing agent doping described in preparing in step 1 is added in step 2 and prepares Argent grain surface modification is carried out in good solution；It takes out and dries, obtain the flexible surface enhancing Raman substrate.

2. preparation method as described in claim 1, which is characterized in that the polymer powder being added in a solvent in step 1 The content of the last and described reducing agent is respectively 1wt%-50wt% and 0.1wt%-20wt%.

3. preparation method as claimed in claim 1 or 2, which is characterized in that in step 1 it is described with reducing agent doping The preparation temperature of thin polymer film is 20 DEG C -200 DEG C, and preparation time is 1-24 hours.

4. preparation method as claimed in claim 1 or 2, which is characterized in that when configuring the solution containing silver ion in step 2, When Bronsted acid is added in the solution, the concentration of Bronsted acid is 0.1wt%-5wt%；When surface is added in the solution When activating agent, the concentration of surfactant is 0.1wt%-5wt%.

5. preparation method as described in claim 1, which is characterized in that the time of Argent grain surface modification described in step 3 is - 5 hours 10 minutes.