Silver nanorod and preparation method and application thereof

Abstract

The application discloses silver nanometer short rods which can be produced in batches, a preparation method and application thereof, and adopts a one-step polyol reduction method to prepare the silver nanometer short rods with a diameter of 30-150 nm and a length of 1-5 microns by comprehensively controlling the concentration of a silver source and a coating agent, the type and dosage of a nucleation control agent, the reaction temperature and time, the heating rate and the cooling rate of the reaction solution and other conditions. The silver nanometer short rods have a small size span, few byproducts, a moderate diameter, are convenient to purify and are not prone to agglomeration. The adding speed and dosage of each raw material in the preparation method do not need to be strictly controlled, which is favorable for reducing the influence of artificial operation on the reaction process; no external force such as stirring is applied in the oxidation-reduction reaction process, so that the reaction system is not sensitive to the volume, and thus the silver nanometer short rod product sizes in different reaction volumes are uniform by slightly adjusting the concentrations of the reactants and the reaction conditions.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of metal nanomaterials, and in particular to a batch-produced silver nanorod and a preparation method and application thereof. BACKGROUND

[0002] Micro-sized silver powder has an irreplaceable role in the field of electronic packaging, but its performance improvement space is limited and it has been unable to meet the development needs of high-thermal-conductivity and high-service-reliability of the thermal interface layer in the field of electronic packaging. Nano-silver material has a low melting point characteristic, and its composite addition or full replacement of micro-sized silver powder as conductive filler is an important research direction for performance improvement of the thermal interface material. The length of nano-silver wire can reach 30-50 μm, and the use process will block the needle or screen, which seriously affects the dispensing and printing performance. In addition, nano-silver particles are difficult to separate and purify, have high use cost, and are prone to agglomeration and have high organic content. Therefore, it has great theoretical research significance and application value to develop a batch-produced high-yield silver nanorod.

[0003] At present, the preparation process of nano-silver particles, nano-silver wires and nano-silver sheets is relatively mature, but the research on silver nanorods is still less. The existing preparation methods of silver nanorods have the problems of low yield, large size span (0.1-10 μm), many by-products (candle-shaped, cubic, particles, long wires), and small diameter leading to difficult separation and purification and easy agglomeration. SUMMARY

[0004] The present application provides a batch-produced silver nanorod and a preparation method and application thereof, which are used to overcome the defects of low yield, large size span, many by-products, and small diameter in the prior art.

[0005] To achieve the above-mentioned purpose, the present application provides a preparation method of a batch-produced silver nanorod, which comprises the following steps:

[0006] S1: under room temperature conditions, polyhydric alcohol, polyvinylpyrrolidone solution with a concentration of 0.5-3 mol / L, and nucleation control agent solution with a concentration of 0.01-10 mmol / L are added to an equal-diameter glass reaction container, the temperature is raised to 150-180℃ at a rate of 2-20℃ / min while stirring, the temperature field fluctuation of the reaction solution is less than 5℃, and the stirring device is turned off;

[0007] S2: silver nitrate solution with a concentration of 0.2-1.0 mol / L is added to the equal-diameter glass reaction container, and the reaction is carried out at 150-180℃ for 0.5-5 h, then the reaction solution is cooled at a rate of 1-40℃ / min, and filtration is performed to obtain silver nanorods.

[0008] In order to achieve the above object, the application further provides the silver nanometer short rod which can be produced in batches and is prepared by the preparation method.

[0009] In order to achieve the above object, the application further provides the application of the silver nanometer short rod which can be produced in batches, and the silver nanometer short rod prepared by the preparation method or the silver nanometer short rod is applied to the packaging interconnection field between ceramic, metal and glass electronic components in integrated circuits or printed circuits, the photocatalysis field and the antibacterial medical instrument.

[0010] Compared with the prior art, the application has the following beneficial effects:

[0011] 1. The preparation method of the silver nanometer short rod which can be produced in batches provided by the application adopts one-step polyol reduction method, the adding speed and dosage of each raw material do not need to be strictly controlled, which is beneficial to reduce the influence of human operation on the reaction process; in addition, no external force such as stirring is applied in the oxidation-reduction reaction process, so that the reaction system is not sensitive to the volume, and thus the product size of the silver nanometer short rod of different reaction volumes can be uniform by adjusting the concentration of each reactant and the reaction condition. In addition, the one-step polyol reduction method has simple process, low equipment cost and process cost, good batch stability, uniform and controllable product size, can be produced in batches, has simple separation and purification process, and the yield is greater than 85%.

[0012] 2. The preparation method provided by the application can prepare the silver nanometer short rod with a diameter of 30-150 nm and a length of 1-5 μm by comprehensively adjusting the concentration of the silver source and the coating agent, the type and dosage of the nucleation control agent, the reaction temperature and time, the heating rate and the cooling rate of the reaction solution and other conditions. The silver nanometer short rod has small size span, few by-products, moderate diameter, is convenient for purification and is not easy to agglomerate. BRIEF DESCRIPTION OF DRAWINGS

[0013] In order to more clearly illustrate the technical solutions in the embodiments of the application or the prior art, the following will briefly introduce the drawings needed to be used in the embodiments or the prior art description. Obviously, the drawings in the following description only show some embodiments of the application, and for those skilled in the art, other drawings can also be obtained according to the structures shown in the drawings without creative labor.

[0014] Figure 1 It is a scanning electron microscope (SEM) photo of the silver nanowire prepared in Example 1, and the scale is 3 μm;

[0015] Figure 2 It is a scanning electron microscope (SEM) photo of the silver nanowire prepared in Example 1, and the scale is 1 μm;

[0016] Figure 3 A scanning electron microscope (SEM) photo of the silver nanowires prepared in Example 2, with a scale of 2 μm.

[0017] Figure 4 A scanning electron microscope (SEM) photo of the silver nanowires prepared in Example 2, with a scale of 1 μm.

[0018] Figure 5 A scanning electron microscope (SEM) photo of the silver nanowires prepared in Example 3, with a scale of 2 μm.

[0019] Figure 6 A scanning electron microscope (SEM) photo of the silver nanowires prepared in Example 3, with a scale of 1 μm.

[0020] The implementation, functional features and advantages of the present application will be further described with reference to the embodiments and the accompanying drawings. DETAILED DESCRIPTION

[0021] The technical solutions in the embodiments of the present application will be described clearly and completely below with reference to the accompanying drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments of the present application. Based on the embodiments in the present application, all the other embodiments obtained by a person of ordinary skill in the art without any creative work, fall within the protection scope of the present application.

[0022] In addition, the technical solutions in the embodiments of the present application can be combined with each other, but it must be based on the fact that a person of ordinary skill in the art can realize the combination. When the combination of technical solutions appears to be contradictory or unachievable, it should be considered that the combination of technical solutions does not exist, and is not within the protection scope of the present application.

[0023] Unless otherwise specified, the medicines / reagents used are commercially available.

[0024] The present application provides a preparation method of silver nanorods which can be mass-produced, comprising the following steps:

[0025] S1: under room temperature, polyhydric alcohol, polyvinylpyrrolidone solution with a concentration of 0.5-3 mol / L, and nucleation control agent solution with a concentration of 0.01-10 mmol / L are added into an isodiametric glass reaction container, and the temperature is raised to 150-180 °C at a rate of 2-20 °C / min while stirring, and then the stirring device is turned off;

[0026] S2: adding silver nitrate solution with a concentration of 0.2-1.0 mol / L into an equal-diameter glass reaction container, reacting at 150-180 ℃ for 0.5-5 h, then cooling the reaction solution at a rate of 1-40 ℃ / min, filtering, and obtaining silver nanorods.

[0027] The equal-diameter glass reaction container is used to control the temperature field fluctuation of the reaction solution to be ≤5 ℃. The silver nanorods are very sensitive to the reaction temperature, and the temperature fluctuation must be strictly controlled to obtain uniform size. In general, the polyol method for preparing silver nanorods is to place the reaction container in an oil bath or to use an external heating circulation device. When the external temperature field is large enough or the power of the reaction equipment is large, the temperature fluctuation of the reaction solution can be controlled in a very small range.

[0028] Preferably, the molar ratio of the silver nitrate solution and the polyvinylpyrrolidone solution is 1:4-1:8. The ratio of the silver source and the coating agent is controlled to better control the size of the obtained silver nanorods.

[0029] Preferably, the molecular weight of the polyvinylpyrrolidone is 30,000-1,500,000. The polyvinylpyrrolidone is oriented to coat on the specific crystal face of silver to make it grow in a direction, and when the molecular weight of the polyvinylpyrrolidone is too small, effective coating cannot be achieved, and the product is a particle; when the molecular weight of the polyvinylpyrrolidone is too large, the molecular chain is too long, and all the crystal faces of silver are wrapped, and the product is still a particle.

[0030] Preferably, the polyol is analytical pure and does not contain impurities such as alcohol, methanol, and halide.

[0031] Preferably, the solvent of the polyvinylpyrrolidone solution is polyol, and the solvent of the nucleation control agent solution is polyol.

[0032] Preferably, the nucleation control agent is at least one of sodium chloride, sodium bromide, potassium chloride, potassium bromide, potassium iodide, copper chloride, iron chloride, and manganese chloride.

[0033] Preferably, in step S1, the stirring rate is 50-200 r / min.

[0034] Preferably, in step S2, the adding rate of the silver nitrate solution is 1-6 L / min. The adding speed of silver nitrate directly affects the reduction and growth speed of silver ions and greatly affects the change of the reaction solution temperature, so the adding speed needs to be considered comprehensively.

[0035] The application further provides a batch-produced silver nanorod prepared by the above preparation method. The silver nanorod has a diameter of 30-150 nm, a length of 1-5 μm, and a yield of greater than 85%.

[0036] This invention also proposes an application of mass-producible silver nanorods, which can be applied to the packaging and interconnection of electronic components such as ceramics, metals and glass in integrated circuits or printed circuits, photocatalysis, and antibacterial medical devices.

[0037] Example 1

[0038] This embodiment provides a method for preparing silver nanorods that can be mass-produced, including the following steps:

[0039] At room temperature, ethylene glycol, a 1.5 mol / L ethylene glycol solution of polyvinylpyrrolidone (PVP), and a 1 mmol / L ethylene glycol solution of FeCl3 were added simultaneously to a cylindrical glass reaction vessel. The vessel was then placed in an oil bath at 150°C, and the components were thoroughly mixed under stirring at 100 rpm. Once the reaction solution reached 150°C, the stirring was stopped, and a 0.3 mol / L silver nitrate solution was rapidly added to the reaction solution at a rate of 2 L / min. The reaction time was 0.5 h. After the oil bath was allowed to cool naturally (at a cooling rate of 1-5°C / min), a mother liquor of nanorods was obtained. After filtration, silver nanorods were obtained with a yield of approximately 93%. Figure 1 and Figure 2 This is a scanning electron microscope (SEM) image of the silver nanorods prepared in this embodiment. Figure 1 The scale bar is 3 μm, and the length of the nanorods is 1-5 μm. Figure 2 The scale bar is 1 μm, and the diameter of the nanorods is 80-150 nm.

[0040] Example 2

[0041] This embodiment provides a method for preparing silver nanorods that can be mass-produced, including the following steps:

[0042] At room temperature, ethylene glycol, a 1.5 mol / L ethylene glycol solution of polyvinylpyrrolidone (PVP), a 1 mmol / L ethylene glycol solution of CuCl2, and a 0.5 mmol / L ethylene glycol solution of KBr were added simultaneously to a cylindrical glass reaction vessel. The vessel was then placed in an oil bath at 150°C, and the components were thoroughly mixed under stirring at 100 rpm. Once the reaction solution reached 150°C, the stirring was stopped, and a 0.3 mol / L silver nitrate solution was rapidly added to the reaction solution at a rate of 1 L / min. The reaction time was 2 h. The reaction solution was then removed and cooled with water at room temperature (cooling rate approximately 30-40°C / min) to obtain a mother liquor of nanorods. After filtration, silver nanorods were obtained with a yield of approximately 85%. Figure 3 andFigure 4 This is a scanning electron microscope (SEM) image of the silver nanorods prepared in this embodiment. Figure 3 The scale bar is 2 μm, and the length of the nanorods is 1-2 μm. Figure 4 The scale bar is 1 μm, and the diameter of the nanorods is 30-60 nm.

[0043] Example 3

[0044] This embodiment provides a method for preparing mass-producible nanorods, including the following steps:

[0045] At room temperature, glycerol, a 3 mol / L solution of polyvinylpyrrolidone (PVP) in glycerol, and an 8 mmol / L solution of NaCl in glycerol were added simultaneously to a cylindrical glass reaction vessel. The vessel was then placed in an oil bath at 170°C, and the components were thoroughly mixed under stirring at 200 rpm. Once the reaction solution reached 170°C, the stirring was stopped, and a 1.0 mol / L silver nitrate solution was rapidly added to the reaction solution at a rate of 4 L / min. The reaction time was 0.5 h. After cooling at a rate of 1-5°C / min, a mother liquor of nanorods was obtained. The solution was filtered to obtain silver nanorods with a yield of approximately 85%. Figure 5 and Figure 6 This is a scanning electron microscope (SEM) image of the silver nanorods prepared in this embodiment. Figure 5 The scale bar is 2 μm, and the length of the nanorods is 1-2 μm. Figure 6 The scale bar is 1 μm, and the diameter of the nanorods is 50-100 nm.

[0046] The above description is merely a preferred embodiment of the present invention and does not limit the patent scope of the present invention. Any equivalent structural transformations made using the contents of the present invention's specification and drawings under the inventive concept of the present invention, or direct / indirect applications in other related technical fields, are included within the patent protection scope of the present invention.

Claims

1. A method for preparing mass-producible nanorods, characterized in that, Includes the following steps: S1: At room temperature, add polyol, polyvinylpyrrolidone solution with a concentration of 0.5~3 mol / L, and nucleation control agent solution with a concentration of 0.01~10 mmol / L to a glass reaction vessel of equal diameter. While stirring, raise the temperature to 150~180℃ at a rate of 2~20℃ / min. The stirring rate is 50~200 r / min. The temperature fluctuation of the reaction solution is less than 5℃. Then turn off the stirring device. The solvent for the polyvinylpyrrolidone solution is a polyol; The solvent for the nucleation control agent solution is a polyol; The nucleation control agent is at least one of sodium chloride, sodium bromide, potassium chloride, potassium bromide, potassium iodide, copper chloride, ferric chloride, and manganese chloride. S2: A silver nitrate solution with a concentration of 0.2~1.0 mol / L is added to a glass reaction vessel of equal diameter. The molar ratio of the silver nitrate solution to the polyvinylpyrrolidone solution is 1:4~1:

8. The molecular weight of the polyvinylpyrrolidone is 30,000~1,500,000. The silver nitrate solution is added at a rate of 1~6 L / min. The reaction is carried out at 150~180℃ for 0.5~5 h. Then the reaction solution is cooled at a rate of 1~40℃ / min and filtered to obtain silver nanorods with a diameter of 30~150 nm and a length of 1~5 μm, and a yield greater than 85%.

2. The method for preparing mass-producible nanorods according to claim 1, characterized in that, The polyol is either ethylene glycol or glycerol, both of which are analytical grade.

3. A mass-producible silver nanorod, characterized in that, The silver nanorods are prepared by a method for mass production of nanorods as described in claim 1 or 2; the diameter of the silver nanorods is 30~150nm and the length is 1~5μm.

4. An application of a mass-producible silver nanorod, characterized in that, The silver nanorods prepared by the method for preparing mass-producible nanorods according to claim 1 or 2, or the silver nanorods according to claim 3, can be applied to the fields of packaging and interconnection between ceramic, metal and glass electronic components in integrated circuits or printed circuits, photocatalysis, and antibacterial medical devices.

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