This paper describes a novel self-assembly behavior of Ag2O nanoparticles to Ag2O nanowires. In the alkaline water-alcohol solution, Ag+ ions reacted with OH- ions on silica nanoparticles functionalized by N-(2-aminoethyl) 3-aminopropyl-trimethoxy-silane (AEAPTS) to form Ag2O nanoparticles. The Ag2O nanoparticles further self-assembled into Ag2O nanowires. The morphology of Ag2O nanowires could be controlled by adjusting Ag/Si molar ratios in the systems. With low Ag/Si molar ratio, uniform Ag2O nanowires were obtained with diameter of about 50 nm and length of tens micrometers. With the increase of Ag/Si molar ratio, Ag2O nanowires became thicker, shorter and irregular. It was shown by high-resolution transmission electron microscopy (HRTEM) that all Ag2O nanowires consisted of tiny Ag2O nanoparticles with diameter of 10-20 nm. The self-assembly of Ag2O nanoparticles into Ag2O nanowires was observed by transmission electron microscopy (TEM) and the corresponding growth mechanism was proposed. (C) 2007 Elsevier B.V. All rights reserved.