| 摘要 |
PROBLEM TO BE SOLVED: To prepare nano-sized fine gold particles having a high purity easily in a simple way without using a reducing agent by mixing chloroauric acid with a solution of polyethyleneimine as a protective polymer and heating and then drying the resultant mixture to disperse fine gold particles in the protective polymer. SOLUTION: Polyethyleneimine is a highly polar high-density polyamine having a branched structure comprising prim., sec., and tert, amines, is rich in reactivity, is liable to form covalent bonds or coordination bonds with gold atoms for forming fine gold particles, inhibits the growth of particles and the formation of secondary particles, and enhances the dispersibility of fine particles. When chloroauric acid and polyethyleneimine are mixed into water and an alcohol and then stirred under heating at 50-150 deg.C, gold ions are reduced by polyethyleneimine to gold atoms and agglomerate to fine particles with sizes of 1-100 nm. The polymer which forms a complex surrounds and protects the fine particles, inhibiting the growth of the particles, Preferably, 1-65 pts.wt. chloroauric acid is mixed with 100 pts.wt. polyethyleneimine.
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