Nanocrystalline Ag2S and Ag have been synthesized by a silane coupling agent (SCA) modified solvothermal method, followed by thermal treatment in N-2 atmosphere. The key of this method is to select bifunctional SCAs with HS- or NH2- ends, which easily couple Ag+ prior to the solvothermal process, while the (H3CO)(3)-Si- ends of SCA easily change into (HO)(3)-Si- ends by hydrolysis reactions. These factors are favorable for the production of nanocrystalline Ag2S and Ag with small nanoparticle size during the solvothermal processes, meanwhile distributed homogeneously in the networks resulting from the polymerization of (HO)(3)-Si- groups. The formed networks effectively inhibit the aggregation and growth of Ag2S and Ag crystallites and keep their monodispersion. The resulting spherical Ag2S and Ag nanoparticles with average diameter of about 10 nm are floatable in water, attributed to the small nanoparticle size and to the formed silane-coupling link. (c) 2012 Elsevier Ltd. All rights reserved.