Metal nanoparticles formed around a nucleus and scalable processes for producing same

Patent metadata

Field	Value
Publication number	US-2016067776-A1
Application number	US-201314028487-A
Country	US
Kind code	A1
Filing date	Sep 16, 2013
Priority date	Sep 27, 2012
Publication date	Mar 10, 2016
Grant date	—

Abstract

Metal nanoparticles and compositions derived therefrom can be used in a number of different applications. Methods for making metal nanoparticles can include providing a first metal salt in a solvent; converting the first metal salt into an insoluble compound that constitutes a plurality of nanoparticle seeds; and after forming the plurality of nanoparticle seeds, reacting a reducing agent with at least a portion of a second metal salt in the presence of at least one surfactant and the plurality of nanoparticle seeds to form a plurality of metal nanoparticles. Each metal nanoparticle can include a metal shell formed around a nucleus derived from a nanoparticle seed, and the metal shell can include a metal from the second metal salt. The methods can be readily scaled to produce bulk quantities of metal nanoparticles.

First claim

What is claimed is the following:

1 . A method comprising:
providing a first metal salt in a solvent; converting the first metal salt into an insoluble compound, the insoluble compound comprising a plurality of nanoparticle seeds; and after forming the plurality of nanoparticle seeds, reacting a reducing agent with at least a portion of a second metal salt in the presence of at least one surfactant and the plurality of nanoparticle seeds to form a plurality of metal nanoparticles, each metal nanoparticle comprising a metal shell formed around a nucleus derived from a nanoparticle seed, and the metal shell comprising a metal from the second metal salt.

2 . The method of claim 1 , wherein converting the first metal salt into an insoluble compound comprises reducing the first metal salt to form the insoluble compound.

3 . The method of claim 2 , wherein the first metal salt and the second metal salt are the same.

4 . The method of claim 2 , wherein the first metal salt and the second metal salt are different.

5 . The method of claim 2 , wherein at least the first metal salt comprises a copper (II) salt.

6 . The method of claim 5 , wherein the first metal salt and the second metal salt each comprise a copper (II) salt.

7 . The method of claim 2 , wherein the first metal salt is reduced by a first portion of the second metal salt.

8 . The method of claim 2 , wherein the first metal salt is reduced by a sugar comprising an oxidizable group.

9 . The method of claim 2 , wherein the first metal salt is reduced by a third metal salt.

10 . The method of claim 9 , further comprising:
separating the insoluble compound from the third metal salt or an oxidation product thereof, prior to reacting the reducing agent with the second metal salt.

11 . The method of claim 1 , wherein the first metal salt is present in an amount ranging between about 0.05 and about 0.25 stoichiometric equivalents relative to the second metal salt.

12 . The method of claim 1 , wherein the nanoparticle seeds are converted to a zero-valent metal while reacting the second metal salt with the reducing agent.

13 . The method of claim 1 , wherein converting the first metal salt into an insoluble compound comprises forming a metal carboxylate, a metal sulfide, colloidal sulfur, a metal hydroxide, a metal chalcogenide, or a metal complex from the first metal salt.

14 . The method of claim 1 , wherein the second metal salt comprises a mixture of two or more metal salts and the plurality of metal nanoparticles produced therefrom comprises alloy nanoparticles.

15 . A method comprising:
providing a first metal salt in a solvent, the first metal salt comprising a copper (II) salt; reducing the first metal salt to form an insoluble copper (I) compound, the insoluble copper (I) compound comprising a plurality of nanoparticle seeds; and after forming the plurality of nanoparticle seeds, reacting a reducing agent with a second metal salt in the presence of at least one surfactant and the plurality of nanoparticle seeds to form a plurality of metal nanoparticles, each metal nanoparticle comprising a metal shell formed around a nucleus derived from a nanoparticle seed, and the metal shell comprising a metal from the second metal salt.

16 . The method of claim 15 , wherein the first metal salt is reduced by a first portion of the second metal salt.

17 . The method of claim 15 , wherein the first metal salt is reduced by a third metal salt.

18 . The method of claim 17 , further comprising:
separating the insoluble copper (I) compound from the third metal salt or an oxidation product thereof, prior to reacting the reducing agent with the second metal salt.

19 . The method of claim 17 , wherein the second metal salt comprises a copper (II) salt.

20 . The method of claim 15 , wherein the first metal salt is present in an amount ranging between about 0.05 and about 0.25 stoichiometric equivalents relative to the second metal salt.

21 . The method of claim 15 , wherein the nanoparticle seeds are converted to a zero-valent metal while reacting the second metal salt with the reducing agent.

22 . A method comprising:
providing a copper (II) salt in a solvent; reducing the copper (II) salt to form an insoluble copper (I) salt having a particle size of about 10 nm or less; after forming the insoluble copper (I) salt, adding at least one surfactant and a reducing agent thereto; and reacting the reducing agent with the insoluble copper (I) salt in the presence of the at least one surfactant to form a plurality of copper nanoparticles.

23 . A metal nanoparticle composition comprising:
metal nanoparticles comprising a metal shell formed around a nucleus derived from a copper (I) nanoparticle seed; and a surfactant coating disposed on the metal shell, the surfactant coating comprising at least one surfactant.

24 . The metal nanoparticle composition of claim 23 , wherein the metal shell comprises copper.

25 . The metal nanoparticle composition of claim 24 , wherein the at least one surfactant comprises a first surfactant comprising a C6-C18 primary alkylamine and a second surfactant comprising an N,N′-dialkylethylenediamine.

26 . The metal nanoparticle composition of claim 24 , wherein the metal nanoparticles range from about 1 nm to about 10 nm in size.

Assignees

• Lockheed Corp

Inventors

• Zinn Alfred A

Classifications

• B82Y40/00

  Manufacture or treatment of nanostructures · CPC title

• B01J13/02

  Making microcapsules or microballoons {(for medical preparations A61K9/50)} · CPC title

• B22F9/18

  with reduction of metal compounds · CPC title

• B22F1/06

  Metallic powder characterised by the shape of the particles (nanosized particles B22F1/054) · CPC title

• B22F1/102

  Metallic powder coated with organic material · CPC title