Method for manufacturing silver nanowires
Provided is a method for producing Ag nanowires, including, heating a precursor solution that includes: an Ag salt; a water-soluble polymer; a surfactant, or a halide of metal ions having a standard reduction potential of −0.1 to −0.9V as a metal catalyst; and a reduction solvent, to produce the Ag nanowires. According to this method, a time for synthesizing nanowires may be considerably decreased, and an amount of Ag precursor discarded without reaction may be effectively reduced. As a result, the Ag nanowires may be produced with high efficiency and mass-production thereof through a simple scale-up may be successfully achieved.
1. A method for producing Ag nanowire, comprising:
(a) preparing a first solution that contains an Ag salt and a first reduction solvent, and a second solution that contains a water-soluble polymer, a surfactant, a viscosity enhancer and a second reduction solvent;
(b) heating the second solution; and
(c) introducing the first solution to the second solution, to produce Ag nanowires, wherein among the second solution in operation (a), a content of the water-soluble polymer ranges from 1 to 15 wt. % and a content of the surfactant ranges from 0.005 to 1 wt. %,
in operation (c), the first and the second solutions are mixed, so that a ratio by weight of the Ag salt of the first solution:the surfactant of the second solution ranges from 100:0.01 to 100:15,
a content of the viscosity enhancer in the second solution is an amount such that a viscosity of a mixture containing the viscosity enhancer, the first reduction solvent and the second reduction solvent is 1.1 to 10 times a viscosity of a mixture of the first reduction solvent and the second reduction solvent at 25° C., and
operation (c) is carried out under a non-agitated state in which no artificial agitation is performed, and a variation in flow rate or turbulence is not caused by an external device.
2. The method of claim 1 , wherein the surfactant is at least one selected from the group consisting of an anionic surfactant, a cationic surfactant and an amphoteric surfactant.
3. The method of claim 2 , wherein the anionic surfactant is at least one selected from the group consisting of sodium laureth sulfate, sodium (C14-C16) olefin sulfonate and sodium dodecyl benzene sulfonate.
4. The method of claim 1 , wherein the water-soluble polymer is at least one selected from the group consisting of polyvinylpyrrolidone, polyvinylalcohol, polyacrylamide, polyacrylic acid and copolymers thereof.
5. The method of claim 4 , wherein a molecular weight (Mw) of the water-soluble polymer ranges from 50,000 to 1,500,000.
6. The method of claim 1 , wherein the temperature of the second solution after step (b) and before step (c) satisfies the following Relation 2:
0.6 T b <T h <0.9 T b (Relation 2)
wherein T h is a heating temperature ° C. of the second solution, and T b is a boiling point ° C. of the second reduction solvent at atmospheric pressure.
7. The method of claim 6 , wherein, when the first solution is introduced in step (c), a variation in the temperature of the second solution satisfies the following Relation 3:
0≦Δ T 2 ≦0.1× T 2 (Relation 3)
wherein T 2 is the temperature ° C. of the second solution after the heating step in (b), and ΔT 2 is a variation in the temperature of the second solution while introducing the first solution to the second solution.
8. The method of claim 1 , wherein a content of the Ag salt of the first solution in step (a) ranges from 15 to 40 wt. %.
9. The method of claim 1 , wherein the Ag salt is at least one selected from the group consisting of silver nitrate, silver acetate, silver perchlorate and silver chloride.
10. The method of claim 1 , wherein the first reduction solvent and the second reduction solvent are polar solvents containing at least one oxygen atom.
11. The method of claim 1 , wherein the first reduction solvent and the second reduction solvent are each independently at least one selected from the group consisting of ethylene glycol, 1,2-propyleneglycol, 1,3-propyleneglycol, diethyleneglycol (DEG)(2-hydroxyethyl ether), glycerol and glucose.
12. The method of claim 1 , wherein the viscosity enhancer is polyethylene glycol.