title: Silica coating of silver nanoparticles using a modified Stober method.
abstract: Silver nanoparticles prepared through a borohydride-reduction method were directly coated with silica by means of a seeded polymerization technique based on the Stober method. Various amine catalysts were used for initialization of a sol-gel reaction of TEOS with no need for a prior surface modification. Use of dimethylamine (DMA) as a catalyst was found to be necessary to obtain a proper coating. The silica shell thickness was varied from 28 to 76 nm for TEOS concentrations of 1-15 mM at 11.1 M water and 0.8 M DMA. The optical spectra of the core-shell silver-silica composite particles show a qualitative agreement with predictions by Mie theory.
authors.affiliation: Department of Chemical Engineering, Graduate School of Engineering, Tohoku University, 07 Aoba, Aramaki-aza, Aoba-ku, Sendai 980-8579, Japan. yoshio@mickey.che.tohoku.ac.jp
authors.forename: Yoshio
authors.initials: Y
authors.lastname: Kobayashi
authors.forename: Hironori
authors.initials: H
authors.lastname: Katakami
authors.forename: Eiichi
authors.initials: E
authors.lastname: Mine
authors.forename: Daisuke
authors.initials: D
authors.lastname: Nagao
authors.forename: Mikio
authors.initials: M
authors.lastname: Konno
authors.forename: Luis M
authors.initials: LM
authors.lastname: Liz-Marzán