Abstract: Silver nanoparticles can be synthesized in liquid crystal systems formed by nonionic surfactant AEO7 and AgNO3 aqueous solution. The surfactant AEO-7 acts as both reductive and protective agent in the synthetic process. In the system of surfactant with ethoxyl groups, it is believed that ethoxyl groups can form hydroperoxides, and these hydroperoxides endow the surfactant the ability of reduction. The effects of reaction time, concentration,temperature and the characters of the liquid crystal system have all been studied. Silver nanoparticles stop growing with the prolonging of reaction time to certain period. This indicates that the particle′s enlarging is due to self-growing process, but not aggregating of particles. And the average diameters of silver particles obtained are all smaller than 10 nm.

Key words: Nanoparticle, Silver, Lyotropic liquid crystal, Nonionic surfactant