Silica coating of silver nanoparticles using a modified Stober method.
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.
Kobayashi
Yoshio
Y
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
Katakami
Hironori
H
Mine
Eiichi
E
Nagao
Daisuke
D
Konno
Mikio
M
Liz-Marzán
Luis M
LM