期刊
JOURNAL OF COLLOID AND INTERFACE SCIENCE
卷 354, 期 2, 页码 887-890出版社
ACADEMIC PRESS INC ELSEVIER SCIENCE
DOI: 10.1016/j.jcis.2010.11.013
关键词
Core-shell; Nanoparticles; Silver; Silica; Sol-gel; Solvent effect
资金
- National Science Foundation (NSF) [CBET-0730990]
- Center for the Exploitation of Nanostructures for Energy and Sensor Applications [HRD-0833180]
- Direct For Education and Human Resources
- Division Of Human Resource Development [833180] Funding Source: National Science Foundation
Combining metal nanoparticles and dielectrics (e.g. silica) to produce composite materials with high dielectric constant is motivated by application in energy storage. Control over dielectric properties and their uniformity throughout the composite material is best accomplished if the composite is comprised of metal core - dielectric shell structured nanoparticles with tunable dimensions. We have synthesized silver nanoparticles in the range of 40-100 nm average size using low concentration of saccharide simultaneously as the reducing agent and electrostatic stabilizer. Coating these silver particles with silica from tetraalkoxysilanes has different outcomes depending on the alcoholic solvent and the silver particle concentration. A common issue in solution-based synthesis of core-shell particles is heterogeneous nucleation whereupon two populations are formed: the desired core-shell particles and undesired coreless particles of the shell material. We report the formation of Ag@SiO2 core-shell particles without coreless silica particles as the byproduct in 2-propanol. In ethanol, it depends on the silver surface area available whether homogeneous nucleation of silica on silver is achieved. In methanol and 1-butanol, core-shell particles did not form. This demonstrates the significance of controlling the tetraalkoxysilane hydrolysis rate when growing silica shells on silver nanoparticles. (C) 2010 Elsevier Inc. All rights reserved.
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