Water-phase synthesis method of nano silver wire with high length-diameter ratio

Abstract

The invention discloses a high-length-diameter-ratio nano silver wire water phase synthesis method which comprises the following steps: 1, dissolving fructose, sodium citrate and 1-butyl-1-methylpyrrolidine chloride in deionized water to obtain a solution A; 2, dissolving silver nitrate in deionized water to obtain a solution B; 3, adding the solution B into the solution A to obtain a mixed solution C; 4, after the mixed solution C is subjected to a heating reaction, silver wire mother liquor is obtained; and 5, processing the silver wire mother liquor to obtain the nanometer silver wire. The water-phase synthesis method of the nano silver wire with the high length-diameter ratio has the advantages that the length-diameter ratio can be easily and accurately controlled, the synthesis process is simple, the yield is high, and environmental protection is achieved, the obtained nano silver wire has the advantages that no residual macromolecules exist on the surface of the silver wire, the length-diameter ratio is uniform, particularly, the diameter of the silver wire can be accurately controlled, and the water-phase synthesis method of the nano silver wire with the high length-diameter ratio is suitable for large-scale production. The error of the obtained silver wire diameter distribution range is + / -3nm, which is far beyond that of other aqueous phase synthesis methods.

Description

Technical Field

[0001] The invention belongs to the field of nano-metal conductive material production and relates to a method for preparing nano-silver wires with precisely controllable aspect ratio in an aqueous phase. Background Art

[0002] With the development and progress of the times, various smart devices have been integrated into various fields and play an important role in various fields, so the manufacture of smart devices has received more and more attention from people. As the input component of smart devices, the touch screen is mainly composed of protective glass, conductive film, touch chip, optical glue and other components. At present, the ITO conductive film with excellent conductivity and light transmittance is the mainstream transparent conductive film material on the market, and the indium tin oxide (ITO) conductive film technology is mature, so the ITO conductive film occupies more than 90% of the market share of small-size touch screens. However, the shortcomings of ITO transparent conductive film are also obvious. First, the In in the ITO conductive film is a rare metal, which is expensive and has the problem of increasing depletion. Second, the preparation process is complicated. It is mainly prepared by depositing on a substrate such as PET through a process such as magnetron sputtering. The obtained ITO conductive film has defects such as low yield of large-size products, excessive resistance, and poor bending resistance, which greatly limits its application in the direction of large-size touch screens and flexible touch screens. Nano silver wire is a good material that combines electrical and optical properties. Due to its good photoelectric properties, it is hailed as one of the most ideal materials that is most likely to surpass ITO thin film in the 21st century. Nano silver wire has important applications in the fields of conductivity, catalysis, biomedicine, antibacterial and optics due to its high conductivity, high light transmittance, strong bending resistance and low production cost.

[0003] At present, the preparation methods of silver nanowires are mainly divided into two categories: physical synthesis method and chemical synthesis method. Among them, the template method and gas phase synthesis method belong to physical synthesis method; the polyol method and hydrothermal method belong to chemical synthesis method. In industry, the polyol method is currently the most common method for producing silver nanowires. It has the characteristics of simple process, easy control, high output, simple equipment, etc. However, the polyol method also has some limitations that affect its subsequent development, such as high reaction temperature, polyvinyl pyrrolidone attached to the surface of the silver wire is difficult to clean, and the reaction organic waste liquid is difficult to handle.

[0004] The aqueous synthesis method of silver nanowires is a new method for synthesizing silver nanowires in recent years and a new trend for the synthesis of silver nanowires in the future. Since the silver nanowires are synthesized in water and polyvinyl pyrrolidone is no longer used as a capping agent during the synthesis process, the aqueous synthesis method of silver nanowires has the advantages of mild reaction temperature, green environmental protection, and no residual polymer on the surface of the silver wires. However, the aqueous synthesis method of silver nanowires also has some disadvantages, such as the inability to accurately control the aspect ratio of the silver wires and low yield, which seriously affect its large-scale application. Summary of the invention

[0005] In view of the above technical problems, the present invention provides a new aqueous phase synthesis method for high aspect ratio nano silver wires. The new method has the advantages of mild reaction temperature, green environmental protection, simple synthesis process, no residual polymer on the surface of the silver wire, precise control of aspect ratio, and high yield.

[0006] The technical solution adopted by the present invention is: a method for synthesizing nano silver wires with a high aspect ratio in an aqueous phase, the method comprising the following steps:

[0007] (1) Weigh fructose, sodium citrate, and 1-butyl-1-methylpyrrolidino chloride and dissolve them in deionized water. Stir and dissolve to obtain solution A for later use.

[0008] (2) Weigh silver nitrate and dissolve it in deionized water. Stir and ultrasonically dissolve it to obtain solution B for later use.

[0009] (3) Slowly add solution B into solution A while stirring to obtain a milky white suspension mixture C for standby use;

[0010] (4) taking out the polytetrafluoroethylene liner in the hydrothermal synthesis kettle, slowly pouring the mixed solution C into the liner, putting the liner back into the hydrothermal synthesis kettle, and tightening the lid of the hydrothermal synthesis kettle;

[0011] (5) placing the hydrothermal synthesis kettle in an oil bath for heating to carry out a water-phase synthesis reaction of nano silver wires, and obtaining a silver wire mother solution D after a period of reaction;

[0012] (6) treating the silver wire mother solution D by centrifugation with deionized water and ethanol to obtain nano silver wires;

[0013] In the steps 1 and 2, the preferred mass ratio of 1-butyl-1-methylpyrrolidine chloride: sodium citrate: fructose: silver nitrate is 1: (1-20): (2-20): (1-10);

[0014] In step 5, the preferred oil bath temperature is 80 to 120° C., and the preferred reaction time is 5 to 30 hours;

[0015] In step 6, the obtained silver wire has a diameter of 15 to 60 nm and a length of 10 to 60 μm.

[0016] The present invention proposes a method for synthesizing nano silver wires in an aqueous phase with a high aspect ratio, using fructose as a reducing agent, sodium citrate as a surfactant, and 1-butyl-1-methylpyrrolidine chloride as a nucleation control agent. The method can synthesize nano silver wires in an aqueous phase at a relatively low synthesis temperature and a relatively short reaction time. The method has the advantages of easy and accurate control of the aspect ratio, simple synthesis process, high yield, and green environmental protection. The obtained nano silver wires have the characteristics of no residual polymer on the surface of the silver wire and uniform aspect ratio. In particular, the diameter of the silver wire can be accurately controlled, and the error of the distribution range of the diameter of the silver wire is obtained to be ±3nm, which is far beyond the reach of other aqueous phase synthesis methods. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 This is a high-magnification transmission electron microscopy image of the silver nanowires prepared in Example 1 of the present invention.

[0018] Figure 2 This is a low-magnification transmission electron microscopy image of the silver nanowires prepared in Example 1 of the present invention.

[0019] Figure 3 This is a high-magnification transmission electron microscopy image of the nanosilver wire prepared in Example 2 of the present invention.

[0020] Figure 4 This is a low-magnification transmission electron microscopy image of the silver nanowires prepared in Example 2 of the present invention.

[0021] Figure 5 This is a high-magnification transmission electron microscopy image of the nanosilver wire prepared in Example 3 of the present invention.

[0022] Figure 6 This is a low-magnification transmission electron microscopy image of the nanosilver wire prepared in Example 3 of the present invention. DETAILED DESCRIPTION

[0023] The embodiments of the present invention are described in detail. The embodiments are implemented on the premise of the technical solution of the present invention, and detailed implementation methods and specific operation processes are given, but the protection scope of the present invention is not limited to the following embodiments.

[0024] Embodiment 1: The technical solution adopted by the present invention is: a method for synthesizing nano silver wires with a high aspect ratio in an aqueous phase, the method comprising the following steps:

[0025] (1) Weigh 0.6 g of fructose, 0.5 g of sodium citrate, and 0.2 g of 1-butyl-1-methylpyrrolidino chloride and dissolve them in 100 g of deionized water. Stir and dissolve to obtain solution A for later use.

[0026] (2) Weigh 0.3 g of silver nitrate and dissolve it in 10 g of deionized water. Stir and ultrasonically dissolve the solution to obtain solution B for later use.

[0027] (3) Slowly add solution B into solution A while stirring to obtain a milky white suspension mixture C for standby use;

[0028] (4) taking out the polytetrafluoroethylene liner in the hydrothermal synthesis kettle, slowly pouring the mixed solution C into the liner, putting the liner back into the hydrothermal synthesis kettle, and tightening the lid of the hydrothermal synthesis kettle;

[0029] (5) placing the hydrothermal synthesis reactor in an oil bath at 100° C. and heating it to perform a water-phase synthesis reaction of nano silver wires for 10 hours to obtain a silver wire mother solution D;

[0030] (6) The silver wire mother solution D was centrifuged with deionized water and ethanol to obtain nano silver wires. Transmission electron microscopy showed that the obtained silver wires had a diameter of 20 nm and a length of 23 μm. Figure 1 , 2 shown.

[0031] Embodiment 2: The technical solution adopted by the present invention is: a method for synthesizing nano silver wires with a high aspect ratio in an aqueous phase, the method comprising the following steps:

[0032] (1) Weigh 1 g of fructose, 0.5 g of sodium citrate, and 0.3 g of 1-butyl-1-methylpyrrolidino chloride and dissolve them in 100 g of deionized water. Stir and dissolve to obtain solution A for later use.

[0033] (2) Weigh 0.8 g of silver nitrate and dissolve it in 10 g of deionized water. Stir and ultrasonically dissolve the solution to obtain solution B for later use.

[0034] (3) Slowly add solution B into solution A while stirring to obtain a milky white suspension mixture C for standby use;

[0035] (4) taking out the polytetrafluoroethylene liner in the hydrothermal synthesis kettle, slowly pouring the mixed solution C into the liner, putting the liner back into the hydrothermal synthesis kettle, and tightening the lid of the hydrothermal synthesis kettle;

[0036] (5) placing the hydrothermal synthesis reactor in an oil bath at 90° C. to heat the reaction vessel to perform aqueous synthesis of silver nanowires for 20 hours to obtain silver nanowire mother liquor D;

[0037] (6) The silver wire mother solution D was centrifuged with deionized water and ethanol to obtain nano silver wires. Transmission electron microscopy showed that the obtained silver wires had a diameter of 40 nm and a length of 45 μm. Figure 3 , 4 shown.

[0038] Embodiment 3: The technical solution adopted by the present invention is: a method for synthesizing nano silver wires with a high aspect ratio in an aqueous phase, the method comprising the following steps:

[0039] (1) Weigh 2 g of fructose, 1 g of sodium citrate, and 0.5 g of 1-butyl-1-methylpyrrolidine chloride and dissolve them in 100 g of deionized water. Stir and dissolve to obtain solution A for later use.

[0040] (2) Weigh 1.5 g of silver nitrate and dissolve it in 10 g of deionized water. Stir and ultrasonically dissolve the solution to obtain solution B for later use.

[0041] (3) Slowly add solution B into solution A while stirring to obtain a milky white suspension mixture C for standby use;

[0042] (4) taking out the polytetrafluoroethylene liner in the hydrothermal synthesis kettle, slowly pouring the mixed solution C into the liner, putting the liner back into the hydrothermal synthesis kettle, and tightening the lid of the hydrothermal synthesis kettle;

[0043] (5) placing the hydrothermal synthesis reactor in an oil bath at 100° C. and heating it to perform a water-phase synthesis reaction of nano silver wires for 25 hours to obtain a silver wire mother solution D;

[0044] (6) The silver wire mother solution D is centrifuged with deionized water and ethanol to obtain nano silver wires. Transmission electron microscopy test shows that the obtained silver wires have a diameter of 50 nm and a length of 50 μm. Figure 5 , 6 shown.

Claims

1. A method for synthesizing silver nanowires with a high aspect ratio in aqueous phase, characterized in that: The method comprises the following steps: (1) Weigh sodium citrate, fructose, and 1-butyl-1-methylpyrrolidino chloride and dissolve them in deionized water. Stir and dissolve to obtain solution A for later use. (2) Weigh silver nitrate and dissolve it in deionized water. Stir and ultrasonically dissolve it to obtain solution B for later use. (3) Slowly add solution B into solution A while stirring to obtain a milky white suspension mixture C for standby use; (4) taking out the polytetrafluoroethylene liner in the hydrothermal synthesis kettle, slowly pouring the mixed solution C into the liner, putting the liner back into the hydrothermal synthesis kettle, and tightening the lid of the hydrothermal synthesis kettle; (5) placing the hydrothermal synthesis kettle in an oil bath for heating to carry out a water-phase synthesis reaction of nano silver wires, and obtaining a silver wire mother solution D after a period of reaction; (6) The silver wire mother solution D is centrifuged with deionized water and ethanol to obtain nano silver wires.

2. The method for synthesizing silver nanowires with a high aspect ratio in aqueous phase according to claim 1, characterized in that: In the step (1), the mass ratio of 1-butyl-1-methylpyrrolidine chloride to sodium citrate is 1:(1-20).

3. The method for synthesizing silver nanowires with a high aspect ratio in aqueous phase according to claim 1, characterized in that: In the step (1), the mass ratio of 1-butyl-1-methylpyrrolidine chloride to fructose is 1:(2-20).

4. The method for synthesizing silver nanowires with a high aspect ratio in aqueous phase according to claim 1, characterized in that: In the step (2), the mass ratio of 1-butyl-1-methylpyrrolidine chloride to silver nitrate is 1:(1-10).

5. The method for synthesizing silver nanowires in aqueous phase with a high aspect ratio according to claim 1, characterized in that: The preferred oil bath temperature in step (5) is 80-120°C.

6. The method for synthesizing silver nanowires with a high aspect ratio in aqueous phase according to claim 1, characterized in that: The preferred reaction time in step (5) is 5 to 30 hours.

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