Flexible composite material as well as preparation method and application thereof in SERS (Surface Enhanced Raman Scattering) detection

Abstract

The invention belongs to the technical field of nano materials, and particularly relates to a flexible composite material and a preparation method and application thereof in SERS (Surface Enhanced Raman Scattering) detection. The preparation method comprises the following steps: carrying out surface roughening treatment on a flexible substrate, dipping the obtained pretreated flexible substrate in a mixed solution, and then dropwise adding a silver ion solution into the mixed solution at a first temperature higher than or equal to 170 DEG C for reaction to obtain a silver seed; rapidly cooling the first-stage reaction solution from the first temperature to room temperature; and then heat preservation treatment is carried out under the second temperature condition, the second temperature is smaller than or equal to 150 DEG C, nanowire-shaped silver nanoparticles are obtained on the flexible substrate, and the flexible composite material is obtained. The flexible composite material provided by the invention successfully grows on a flexible substrate to obtain uniformly dispersed silver nanowires. The successful preparation of the flexible composite material is expected to realize SERS detection of early myocardial infarction, and the flexible composite material can be popularized and applied to the fields of food safety, environmental protection and the like.

Description

Technical Field

[0001] The invention belongs to the technical field of nanomaterials, and in particular relates to a flexible composite material and a preparation method thereof and application in SERS detection. Background Art

[0002] Myocardial infarction (MI) is a cardiovascular emergency characterized by myocardial ischemia and necrosis caused by interruption of coronary blood flow. It has an acute onset and a high mortality rate. At present, early screening for acute myocardial infarction mainly uses electrocardiogram and angiography. However, both electrocardiogram and angiography need to be completed in the hospital, which is costly and time-consuming. Therefore, fast and accurate detection technology has become a hot research direction. Surface enhanced Raman spectroscopy (SERS) technology, with its nanoscale signal amplification effect and molecular fingerprint recognition capabilities, can be used in conjunction with the gold-labeled immunochromatographic myocardial infarction detection kit, and is becoming a cutting-edge solution in the field of early rapid detection of myocardial infarction.

[0003] SERS technology enhances the Raman signal of molecules adsorbed on the surface of metal nanoparticles (such as gold and silver) through the surface plasmon resonance effect. SERS detection has the advantages of being fast, efficient and simple to operate. However, due to the need to improve the sensitivity, SERS detection is still unable to detect the occurrence of ultra-early myocardial infarction in a timely manner.

[0004] The sensitivity of SERS detection is closely related to the substrate design. The physicochemical properties of the substrate directly affect the signal enhancement amplitude, stability and applicable scenarios. SERS active substrates are divided into two types: with carriers and without carriers. SERS substrates without carriers are generally composed of metal nanoparticles, which are not easy to store and are not conducive to rapid detection. SERS substrates with carriers can effectively solve these problems by loading the active components on the carrier. Generally speaking, the carriers of SERS substrates are mostly rigid materials such as silicon wafers or glass. Traditional rigid SERS substrates have insufficient contact with the actual sample surface, making them difficult to collect on irregular object surfaces, which is not conducive to on-site detection. Flexible substrates can bend and deform, adapt to various complex and irregular surfaces, and can fully contact the surface of the object to be tested, thereby improving detection efficiency and accuracy. At the same time, flexible substrates are very light, easy to carry and use, can be used for on-site detection, and have broader application prospects.

[0005] However, there are some common problems in loading precious metal particles on flexible materials. For example, metal nanoparticles tend to form irregular aggregates when adsorbed on flexible substrates, and cannot form uniformly dispersed films; and it is impossible to load special morphology (nanowire) particles with better enhancement effects on the surface of flexible substrates. Summary of the invention

[0006] The purpose of the present invention is to provide a flexible composite material, a preparation method thereof and an application in SERS detection. The flexible composite material provided by the present invention successfully grows uniformly dispersed silver nanowires on a flexible substrate, solving the current technical problem that metal nanoparticles are easily agglomerated during adsorption on a flexible substrate and nanowire-like morphology cannot be obtained. The flexible composite material has great application potential in the fields of food safety detection, biomedical detection, environmental pollution detection, etc.

[0007] In order to achieve the above object, the present invention provides the following technical solutions:

[0008] The present invention provides a method for preparing a flexible composite material, comprising the following steps:

[0009] Performing a surface roughening treatment on the flexible substrate to obtain a pretreated flexible substrate;

[0010] The pretreated flexible substrate is immersed in a mixed solution, wherein the mixed solution includes a chloride salt and an organic solvent, and then a silver ion solution is added dropwise to the mixed solution under a first temperature condition to react, wherein the first temperature is ≥170° C., and a silver seed is obtained on the pretreated flexible substrate to obtain a first-stage reaction solution;

[0011] The first-stage reaction solution is cooled from a first temperature to room temperature, and the cooling rate is ≥20°C / min; then, heat preservation treatment is performed under a second temperature condition, and the second temperature is ≤150°C, silver nanoparticles are obtained on the flexible substrate, and the shape of the silver nanoparticles is nanowires, so as to obtain the flexible composite material.

[0012] Preferably, the flexible substrate is an organic fiber cloth.

[0013] Preferably, the organic fiber cloth is polyethylene terephthalate fiber cloth.

[0014] Preferably, the first temperature is 170-180°C;

[0015] The second temperature is 140-150° C.;

[0016] The cooling rate is 20-60°C / min.

[0017] Preferably, the chloride salt comprises an alkali metal chloride, and the organic solvent comprises a polyol; and the molar concentration of the chloride salt in the mixed solution is 0.2 to 0.4 mmol / L.

[0018] Preferably, the mixed solution further comprises an organic dispersant, and the molar concentration of the organic dispersant in the mixed solution is 0.1 to 0.5 mol / L.

[0019] Preferably, the silver ion solution comprises an inorganic silver salt and a polyol, and the molar concentration of silver ions in the silver ion solution is 0.1 to 0.2 mol / L;

[0020] The molar ratio of chloride ions in the chloride salt to silver ions in the silver ion solution is 1:(100-150).

[0021] Preferably, the dripping speed is 0.8 to 1.2 mL / min; the reaction time after the dripping is completed is 30 to 60 min;

[0022] The time of the heat preservation treatment is 1 to 2 hours.

[0023] The present invention provides a flexible composite material prepared by the preparation method described in the above technical solution, comprising a flexible substrate and silver nanoparticles grown on the flexible substrate, wherein the silver nanoparticles are in the shape of nanowires.

[0024] The present invention provides a flexible composite material described in the above technical solution which can be used in SERS detection.

[0025] The present invention provides a method for preparing a flexible composite material, comprising the following steps: performing a surface roughening treatment on a flexible substrate to obtain a pre-treated flexible substrate; immersing the pre-treated flexible substrate in a mixed solution, the mixed solution comprising a chloride salt and an organic solvent, then dropping a silver ion solution into the mixed solution under a first temperature condition for reaction, the first temperature being ≥170°C, obtaining a silver seed on the pre-treated flexible substrate, and obtaining a first-stage reaction solution; cooling the first-stage reaction solution from the first temperature to room temperature, the cooling rate being ≥20°C / min; then performing a heat preservation treatment under a second temperature condition, the second temperature being ≤150°C, obtaining silver nanoparticles on the flexible substrate, the shape of the silver nanoparticles being nanowires, and obtaining the flexible composite material. The present invention forms an uneven surface on the flexible substrate through a surface roughening treatment; then, under the first temperature condition, the silver seed is adsorbed on the uneven surface of the flexible substrate through the dual adsorption of the uneven surface and chloride ions; then, the silver seed is effectively fixed through a cooling process to avoid disordered growth of the silver seed; and finally, under the second temperature condition, the silver seed is slowly grown into nanowire-shaped silver particles. Therefore, the present invention utilizes the step temperature method to successfully control the growth of silver nanoparticles on the flexible substrate through the coordination of different step temperatures, and successfully loads the silver nanowires evenly on the surface of the flexible substrate.

[0026] The present invention successfully grows uniformly dispersed nanowire-shaped silver particles on a flexible substrate using a temperature gradient method. The nanowire-shaped silver particles can optimize the thermoelectric properties of the surface when used as a SERS substrate, thereby obtaining a highly active SERS substrate, which has the characteristics of stable signal and high sensitivity as a SERS substrate. It can stably and sensitively detect markers of early myocardial infarction, and has great application potential in the fields of biomedical testing, food safety testing, environmental pollution testing, etc.

[0027] At the same time, the preparation method provided by the present invention is easy to operate, has simple equipment, uses low-cost reagents, is non-toxic, is environmentally friendly, and is more suitable for industrial application.

[0028] The present invention provides a flexible composite material prepared by the preparation method described in the above technical solution, comprising a flexible substrate and silver nanoparticles grown on the flexible substrate, wherein the silver nanoparticles are in the shape of nanowires. The flexible composite material prepared by the present invention has good stability and is easy to store. It has high detection sensitivity as a SERS substrate and has great application potential in the fields of biomedical detection, food safety detection, environmental pollution detection, etc. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 This is an electron microscope photograph of blank fibers of the polyester fiber cloth used in Example 1 of the present invention;

[0030] Figure 2 This is an electron microscope photograph of the polyester fiber cloth loaded with nanowires prepared in Example 1 of the present invention;

[0031] Figure 3 This is an electron microscope photograph of the nanowire-shaped silver particles prepared in Example 1;

[0032] Figure 4 This is an electron microscope photograph of nanowire-shaped silver particles prepared in Example 2;

[0033] Figure 5 This is an electron microscope photograph of the silver nanoparticles prepared in Comparative Example 1;

[0034] Figure 6 This is an electron microscope photograph of the silver nanoparticles prepared in Comparative Example 2. DETAILED DESCRIPTION

[0035] The present invention provides a method for preparing a flexible composite material, comprising the following steps:

[0036] Performing a surface roughening treatment on the flexible substrate to obtain a pretreated flexible substrate;

[0037] The pretreated flexible substrate is immersed in a mixed solution, wherein the mixed solution includes a chloride salt and an organic solvent, and then a silver ion solution is added dropwise to the mixed solution under a first temperature condition to react, wherein the first temperature is ≥170° C., and a silver seed is obtained on the pretreated flexible substrate to obtain a first-stage reaction solution;

[0038] The first-stage reaction solution is cooled from a first temperature to room temperature, and the cooling rate is ≥20°C / min; then, heat preservation treatment is performed under a second temperature condition, and the second temperature is ≤150°C, silver nanoparticles are obtained on the flexible substrate, and the shape of the silver nanoparticles is nanowires, so as to obtain the flexible composite material.

[0039] In the present invention, unless otherwise specified, all preparation raw materials / components are commercially available products well known to those skilled in the art.

[0040] The present invention performs a surface roughening treatment on a flexible substrate to obtain a pretreated flexible substrate. In the present invention, the flexible substrate is preferably an organic fiber cloth. The organic fiber cloth is preferably a polyethylene terephthalate (PET, polyester) fiber cloth. In the present invention, the surface roughening treatment preferably includes the following steps: immersing the flexible substrate in an alkali solution for alkali treatment to obtain an alkali treatment solution; adding an acid solution to the alkali treatment solution for neutralization and soaking; after the neutralization and soaking are completed, taking out the treated flexible substrate and washing and drying it in sequence to obtain a pretreated flexible substrate. In the present invention, the alkali solution is preferably an aqueous sodium hydroxide solution, and the molar concentration of the aqueous sodium hydroxide solution is preferably 0.1 to 0.2 mol / L. The temperature of the alkali treatment is preferably room temperature, and the time is preferably 10 to 15 min. The acid solution is preferably hydrochloric acid, and the molar concentration of the hydrochloric acid is preferably 0.05 to 0.1 mol / L. The water washing is preferably carried out with deionized water to remove ions in the treated flexible substrate, and the washing is preferably rinsing. The drying is preferably drying.

[0041] After obtaining the pretreated flexible substrate, the present invention immerses the pretreated flexible substrate in a mixed solution, the mixed solution includes a chloride salt and an organic solvent, and then drops a silver ion solution into the mixed solution under a first temperature condition for reaction, the first temperature is ≥170°C, and a silver seed is obtained on the pretreated flexible substrate to obtain a first-stage reaction solution. In the present invention, the chloride salt preferably includes an alkali metal chloride, which may be sodium chloride in an embodiment. The organic solvent preferably includes a polyol, which is preferably a reducing polyol. In an embodiment, it may be ethylene glycol (EG). The molar concentration of the chloride salt in the mixed solution is preferably 0.2 to 0.4 mmol / L, preferably 0.2 to 0.3 mmol / L. The mixed solution preferably also includes an organic dispersant. The organic dispersant is preferably polyvinyl pyrrolidone (PVP). The molar concentration of the organic dispersant in the mixed solution is preferably 0.1 to 0.5 mol / L, preferably 0.2 to 0.45 mol / L. The first temperature is preferably 170 to 180°C.

[0042] In the present invention, the preparation method of the mixed solution preferably comprises the following steps: under a first temperature condition, the pretreated flexible substrate, the organic dispersant and part of the organic solvent are mixed for a first heat preservation to obtain a first solution; under the first temperature condition, the first solution, the chloride salt and the remaining organic solvent are mixed for a second heat preservation to obtain the mixed solution. The time of the first heat preservation is preferably 20 to 30 minutes. The time of the second heat preservation is preferably 20 to 30 minutes. The organic dispersant and part of the organic solvent are mixed in the form of an organic dispersant solution, and the chloride salt and the remaining organic solvent are mixed in the form of a chloride salt solution. The volume ratio of the organic dispersant solution to the chloride salt solution is preferably 20:0.5. The molar concentration of the organic dispersant solution is preferably 0.2 to 0.5 mol / L, more preferably 0.225 to 0.45 mol / L. The molar concentration of the chloride salt solution is preferably 8 to 12 mmol / L, more preferably 10 mmol / L.

[0043] In the present invention, the silver ion solution preferably comprises an inorganic silver salt and a polyol. The inorganic silver salt is preferably silver nitrate. The polyol is preferably ethylene glycol (EG). The molar concentration of silver ions in the silver ion solution is preferably 0.1 to 0.2 mol / L. The molar ratio of chloride ions in the chloride salt to silver ions in the silver ion solution is preferably 1:(100 to 150). In the embodiment, it can be 1:120. In the present invention, the dripping speed is preferably 0.8 to 1.2 mL / min, and in the embodiment, it can be 1 mL / min. The reaction time after the dripping is completed is preferably 30 to 60 min.

[0044] After obtaining the first-stage reaction solution, the present invention cools the first-stage reaction solution from the first temperature to room temperature, and the cooling rate is ≥20°C / min; then, heat preservation treatment is performed under the second temperature condition, and the second temperature is ≤150°C, and silver nanoparticles are obtained on the flexible substrate, and the shape of the silver nanoparticles is nanowires, and the flexible composite material is obtained. In the present invention, the cooling is preferably carried out in an ice water bath. The cooling rate is preferably 20 to 60°C / min, and more preferably 50°C / min. The present invention can effectively control the crystallization behavior of the silver seed by the cooling step and controlling the cooling rate, so that the silver seed can grow into a nanowire morphology with uniform particle size in the subsequent steps, avoiding the irregular granular morphology, and also avoiding the irregular aggregation state.

[0045] In the present invention, the second temperature is preferably 140-150° C. The time of the heat preservation treatment is preferably 1-2 hours. The heat preservation treatment is preferably carried out in a muffle furnace.

[0046] In the present invention, after the heat preservation treatment is completed, the reaction solution obtained after the heat preservation treatment is cooled to room temperature, and then the flexible product is taken out from the reaction solution, and the flexible product is dried to obtain the flexible composite material. The drying is preferably vacuum drying.

[0047] The present invention provides a flexible composite material prepared by the preparation method described in the above technical solution, comprising a flexible substrate and silver nanoparticles grown on the flexible substrate, wherein the silver nanoparticles are in the shape of nanowires.

[0048] In the present invention, the flexible substrate is preferably an organic fiber cloth. The organic fiber cloth is composed of organic fibers. The silver nanoparticles are preferably loaded on the surface of the organic fibers to form a uniform silver film on the surface of the organic fibers. The silver film is formed by silver nanoparticles in the shape of nanowires, and a large number of small pores are formed between the silver nanoparticles of the silver film. The generation of these Raman hot spots will greatly increase the SERS activity of the flexible composite material.

[0049] The present invention provides a flexible composite material described in the above technical solution which can be used in SERS detection.

[0050] In the present invention, the application is preferably: using the flexible composite material as the SERS substrate.

[0051] In order to further illustrate the present invention, the technical solutions provided by the present invention are described in detail below in conjunction with embodiments, but they should not be construed as limiting the protection scope of the present invention.

[0052] Example 1

[0053] (1) The cut PET fiber cloth (3 cm × 3 cm) was soaked in 10 mL of 0.1 M sodium hydroxide solution for 10 min to roughen the surface; then 10 mL of 0.1 M dilute hydrochloric acid solution was added for neutralization for 5 min; the treated PET fiber cloth was taken out and rinsed with 100 mL of deionized water; and finally dried to obtain the pretreated PET fiber cloth.

[0054] (2) Place the pretreated PET fiber cloth into a flask.

[0055] (3) Add 20 mL of 0.225 M PVP-EG solution into the flask and preheat at 170 °C for 30 min.

[0056] (4) Add 0.5 mL of 10 mM NaCl ethylene glycol solution to the flask and preheat for 30 min.

[0057] (5) Add 5 mL of 0.12 MAgNO at a rate of 1.0 mL / min. 3 -EG solution, react for 30 minutes after the addition is completed to obtain a reaction solution.

[0058] (6) The reaction solution was rapidly cooled to room temperature in an ice-water bath at a cooling rate of 50°C / min.

[0059] (7) After preheating the muffle furnace to 140°C, place the reaction solution cooled to room temperature into the muffle furnace and keep it warm for 1 hour before taking it out.

[0060] (8) Taking out the PET fiber cloth from the reaction solution obtained in step (7), placing it in a vacuum drying oven and drying it for 30 minutes, thereby obtaining a flexible composite material.

[0061] The electron microscope photo of the blank fibers in the original state of the PET fiber cloth used in this embodiment is as follows: Figure 1 The electron microscope photo of the silver nanowire-loaded fiber in the flexible composite material prepared in this embodiment is shown in FIG. Figure 2 shown. Figure 3 This is an electron microscope photograph of the nanowire-shaped silver particles prepared in Example 1. Figure 3 The SEM image of the silver nanoparticles obtained in Example 1 was characterized by a scanning electron microscope (SEM, S-4800, Hitachi). Figure 3 It can be seen that the fiber surface is highly covered with nanosilver, and a large number of small pores are formed between the particles. The generation of these Raman hotspots will greatly increase the SERS activity of the flexible composite material.

[0062] Depend on Figure 1 , Figure 2 and Figure 3It can be seen that the flexible composite material is successfully prepared in this embodiment, and the flexible composite material includes PET fiber cloth and silver nanoparticles grown on the PET fiber cloth, and the shape of the silver nanoparticles is nanowires. In this embodiment, the silver nanoparticles grow uniformly on the fiber surface of the PET fiber cloth.

[0063] Example 2

[0064] (1) The cut PET fiber cloth (3 cm × 3 cm) was soaked in 10 mL of 0.1 M sodium hydroxide solution for 10 min to roughen the surface; then 10 mL of 0.1 M dilute hydrochloric acid solution was added for neutralization for 5 min; the treated PET fiber cloth was taken out and rinsed with 100 mL of deionized water; and finally dried to obtain the pretreated PET fiber cloth.

[0065] (2) Place the pretreated PET fiber cloth into a flask.

[0066] (3) Add 20 mL of 0.45 M PVP-EG solution into the flask and preheat at 180 °C for 30 min.

[0067] (4) Add 0.5 mL of 10 mM NaCl ethylene glycol solution to the flask and preheat for 30 min.

[0068] (5) Add 5 mL of 0.12 MAgNO at a rate of 1.0 mL / min. 3 -EG solution, react for 30 minutes after the addition is completed to obtain a reaction solution.

[0069] (6) Rapidly cool the reaction solution to room temperature in an ice-water bath at a cooling rate of 50°C / min.

[0070] (7) After preheating the muffle furnace to 150°C, the reaction solution cooled to room temperature was placed in the muffle furnace and kept warm for 1 hour before being taken out.

[0071] (8) Taking out the PET fiber cloth from the reaction solution obtained in step (7), placing it in a vacuum drying oven and drying it for 30 minutes, thereby obtaining a flexible composite material.

[0072] Figure 4 This is an electron microscope photograph of the nanowire-shaped silver particles prepared in Example 2. Figure 4 The SEM image of the silver nanoparticles obtained in Example 2 was obtained using a scanning electron microscope (SEM, S-4800, Hitachi). Figure 4It can be seen that the flexible composite material was successfully prepared in this embodiment, and the flexible composite material includes PET fiber cloth and silver nanoparticles grown on the PET fiber cloth, and the shape of the silver nanoparticles is nanowires. In this embodiment, the silver nanoparticles grow evenly on the fiber surface of the PET fiber cloth, the nanosilver coverage on the fiber surface is high, and a large number of small pores are formed between the nanowires. The generation of these Raman hotspots will greatly increase the SERS activity of the silver film.

[0073] Comparative Example 1

[0074] (1) The cut PET fiber cloth (3 cm × 3 cm) was soaked in 10 mL of 0.1 M sodium hydroxide solution for 10 min to roughen the surface; then 10 mL of 0.1 M dilute hydrochloric acid solution was added for neutralization for 5 min; the treated PET fiber cloth was taken out and rinsed with 100 mL of deionized water; and finally dried to obtain the pretreated PET fiber cloth.

[0075] (2) Place the pretreated PET fiber cloth into a flask.

[0076] (3) Add 20 mL of 0.45 M PVP-EG solution into the flask and preheat at 180 °C for 30 min.

[0077] (4) Add 0.5 mL of 10 mM NaCl ethylene glycol solution to the flask and preheat for 30 min.

[0078] (5) Add 5 mL of 0.12 MAgNO at a rate of 1.0 mL / min. 3 -EG solution, react for 30 minutes after the addition is completed to obtain a reaction solution.

[0079] (6) After preheating the muffle furnace to 180° C., the reaction solution at a temperature of 180° C. obtained in step (6) is directly placed in the muffle furnace and taken out after being kept warm for 1 hour.

[0080] (7) Taking out the PET fiber cloth from the reaction solution obtained in step (6), placing it in a vacuum drying oven and drying it for 30 minutes, thereby obtaining a flexible composite material.

[0081] Figure 5 This is an electron microscope photo of the silver nanoparticles prepared in Comparative Example 1. Figure 5 It can be seen that in Comparative Example 1, the silver seed is loaded at 180° C. and then grown directly at 180° C. The morphology of the obtained silver nanoparticles is irregular particles, and nanowire-shaped products cannot be formed.

[0082] Comparative Example 2

[0083] (1) The cut PET fiber cloth (3 cm × 3 cm) was soaked in 10 mL of 0.1 M sodium hydroxide solution for 10 min to roughen the surface; then 10 mL of 0.1 M dilute hydrochloric acid solution was added for neutralization for 5 min; the treated PET fiber cloth was taken out and rinsed with 100 mL of deionized water; and finally dried to obtain the pretreated PET fiber cloth.

[0084] (2) Place the pretreated PET fiber cloth into a flask.

[0085] (3) Add 20 mL of 0.45 M PVP-EG solution into the flask and preheat at 180 °C for 30 min.

[0086] (4) Add 0.5 mL of 10 mM NaCl ethylene glycol solution to the flask and preheat for 30 min.

[0087] (5) Add 5 mL of 0.12 MAgNO at a rate of 1.0 mL / min. 3 -EG solution, react for 30 minutes after the addition is completed to obtain a reaction solution.

[0088] (6) After preheating the muffle furnace to 150° C., the reaction solution at 180° C. obtained in step (6) was placed in a muffle furnace at 150° C. and kept warm for 1 hour before being taken out.

[0089] (7) Taking out the PET fiber cloth from the reaction solution obtained in step (6), placing it in a vacuum drying oven and drying it for 30 minutes, thereby obtaining a flexible composite material.

[0090] Figure 6 This is an electron microscope photo of the silver nanoparticles prepared in Comparative Example 2. Figure 6 It can be seen that this comparative example only omits the step of rapid cooling to room temperature, and the obtained nanosilver contains nanowire-like products, but a large number of large particles of irregular nanosilver are mixed therein, indicating that this comparative example does not perform rapid cooling, and the obtained nanosilver product is uneven.

[0091] From the above examples, it can be seen that the method for preparing the flexible composite material provided by the present invention adopts simple equipment and is easy to operate. The reagents used are inexpensive and non-toxic, and the prepared flexible composite material has good repeatability and stability, and can successfully and evenly load nanosilver with special morphology (nanowires).

[0092] Although the above embodiment describes the present invention in detail, it is only a part of the embodiments of the present invention, not all of the embodiments. Other embodiments can be obtained based on this embodiment without creativity, and these embodiments all fall within the protection scope of the present invention.

Claims

1. A method for preparing a flexible composite material, characterized in that: The following steps are involved: Performing a surface roughening treatment on the flexible substrate to obtain a pretreated flexible substrate; The pretreated flexible substrate is immersed in a mixed solution, wherein the mixed solution includes a chloride salt and an organic solvent, and then a silver ion solution is added dropwise to the mixed solution under a first temperature condition to react, wherein the first temperature is ≥170° C., and a silver seed is obtained on the pretreated flexible substrate to obtain a first-stage reaction solution; The first-stage reaction solution is cooled from a first temperature to room temperature, and the cooling rate is ≥20°C / min; then, heat preservation treatment is performed under a second temperature condition, and the second temperature is ≤150°C, silver nanoparticles are obtained on the flexible substrate, and the shape of the silver nanoparticles is nanowires, so as to obtain the flexible composite material.

2. The preparation method according to claim 1, characterized in that: The flexible substrate is organic fiber cloth.

3. The preparation method according to claim 2, characterized in that: The organic fiber cloth is polyethylene terephthalate fiber cloth.

4. The preparation method according to claim 1, characterized in that: The first temperature is 170-180° C. The second temperature is 140-150° C.; The cooling rate is 20-60°C / min.

5. The preparation method according to claim 1, characterized in that: The chloride salt includes alkali metal chloride, and the organic solvent includes polyol; the molar concentration of the chloride salt in the mixed solution is 0.2-0.4 mmol / L.

6. The preparation method according to claim 1 or 5, characterized in that: The mixed solution also includes an organic dispersant, and the molar concentration of the organic dispersant in the mixed solution is 0.1-0.5 mol / L.

7. The preparation method according to claim 1, characterized in that: The silver ion solution comprises an inorganic silver salt and a polyol, and the molar concentration of silver ions in the silver ion solution is 0.1 to 0.2 mol / L; The molar ratio of chloride ions in the chloride salt to silver ions in the silver ion solution is 1:(100-150).

8. The preparation method according to claim 1, characterized in that: The dropping speed is 0.8-1.2 mL / min; the reaction time after the dropping is completed is 30-60 min; The time of the heat preservation treatment is 1 to 2 hours.

9. The flexible composite material prepared by the preparation method according to any one of claims 1 to 8, characterized in that: The invention comprises a flexible substrate and silver nanoparticles grown on the flexible substrate, wherein the silver nanoparticles are in the shape of nanowires.

10. Use of the flexible composite material according to claim 9 in SERS detection.

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