Production of metal nanoparticles

Abstract

A process for the production of metal nanoparticles. The process comprises a rapid mixing of a solution of at least about 0.1 mole of a metal compound that is capable of being reduced to a metal by a polyol with a heated solution of a polyol and a substance that is capable of being adsorbed on the nanoparticles.

1 - 271 . (canceled) 
     
     
         272 . A process for purifying a nanoparticle dispersion, comprising the step of:
 filtering a nanoparticle dispersion comprising nanoparticles, a liquid phase and impurities and/or contaminants through a membrane having a pore size of from about 0.01 μm to about 1 μm and/or a lumen of from about 0.1 mm to about 5 mm, wherein the membrane retains substantially all the nanoparticles in the liquid phase of the nanoparticle dispersion passes through the membrane.   
     
     
         273 . The process of  claim 272 , wherein the nanoparticles comprise metal nanoparticles. 
     
     
         274 . The process of  claim 273 , wherein the metal nanoparticles comprise a metal selected from the group consisting of gold, silver, copper, nickel, cobalt, palladium, platinum, iridium, osmium, rhodium, ruthenium, rhenium, vanadium, chromium, manganese, niobium, molybdenum, tungsten, tantalum, iron and cadmium. 
     
     
         275 . The process of  claim 272 , wherein at least 70% of impurities and/or contaminants in the liquid phase of the nanoparticle suspension pass through the membrane. 
     
     
         276 . The process of  claim 272 , wherein at least 80% of impurities and/or contaminants in the liquid phase of the nanoparticle suspension pass through the membrane. 
     
     
         277 . The process of  claim 272 , wherein at least 90% of impurities and/or contaminants in the liquid phase of the nanoparticle suspension pass through the membrane. 
     
     
         278 . The process of  claim 272 , wherein at least 95% of impurities and/or contaminants in the liquid phase of the nanoparticle suspension pass through the membrane. 
     
     
         279 . The process of  claim 272 , further comprising the step of washing the membrane retaining substantially all of the nanoparticles with a washing liquid to remove impurities and/or contaminants from the surfaces of the nanoparticles. 
     
     
         280 . The process of  claim 279 , wherein the step of washing is repeated more than once. 
     
     
         281 . The process of  claim 279 , wherein the washing liquid is water and/or an organic solvent. 
     
     
         282 . The process of  claim 279 , further comprising the step of removing the washing liquid. 
     
     
         283 . The process of  claim 282 , further comprising the step of drying the metal nanoparticles. 
     
     
         284 . The process of  claim 283 , wherein the dried nanoparticles are capable of being redispersed in a liquid phase. 
     
     
         285 . The process of  claim 272 , wherein the nanoparticles have an average particle size of about 10 nm to about 80 nm. 
     
     
         286 . The process of  claim 272 , wherein the membrane has a pore size of from about 0.01 μm to about 1 μm. 
     
     
         287 . The process of  claim 272 , wherein the membrane comprises a polymeric material. 
     
     
         288 . The process of  claim 287 , wherein the polymeric material comprises at least one of a polysulfone, a polyethersulfone, a sulfonated polysulfone, a polyamide, and a cellulose ester. 
     
     
         289 . The process of  claim 272 , wherein the membrane comprises a ceramic material. 
     
     
         290 . The process of  claim 289 , wherein the ceramic material comprises an oxide of at least one of titanium, zirconium, silicon and aluminum. 
     
     
         291 . The process of  claim 272 , wherein the membrane has a molecular weight cutoff in the range of from about 10,000 to about 1,000,000. 
     
     
         292 . The process of  claim 272 , further comprising the step of treating the surfaces of the nanoparticles of the nanoparticle dispersion with an absorptive substance prior to the step of filtering. 
     
     
         293 . The process of  claim 272 , further comprising the step of increasing the concentration of the nanoparticles in the nanoparticle dispersion prior to the filtering step. 
     
     
         294 . The process of  claim 293 , wherein the step of increasing the concentration of the nanoparticles is performed by drawing the nanoparticle dispersion though a membrane. 
     
     
         295 . The process of  claim 272 , wherein the nanoparticles are produced by rapid mixing of a solution of at least about 0.1 mole of a metal compound that is capable of being reduced to a metal by a polyol with a heated solution that comprises a polyol and a substance that is capable of being adsorbed on the nanoparticles. 
     
     
         296 . The process of  claim 295 , further comprising the step of precipitating the nanoparticles in the nanoparticle dispersion prior to the filtering step. 
     
     
         297 . The process of  claim 272 , wherein the nanoparticle dispersion further comprises one or more adhesion promoters and/or humectants. 
     
     
         298 . The process of  claim 272 , further comprising the step of creating a printing formulation, ink or paste from the filtered nanoparticle dispersion.