Please use this identifier to cite or link to this item: http://repositorio.unicamp.br/jspui/handle/REPOSIP/57214
Type: Artigo de periódico
Title: Core-and-shell nature of Strober silica particles
Author: Leite, CAP
de Souza, EF
Galembeck, F
Abstract: Two different samples of monodisperse Stober silica particles were examined in the analytical transmission electron microscope, using different imaging modes: bright-field, dark-field, energy-loss and elemental distribution maps. The particles (effective diameters = 141 and 36 nm) are formed by domains of variable O/Si ratio, which is consistent with a variable degree of hydration, and they coexist with particles with a high O/Si ratio measuring a few nanometers only, which appear dispersed in the picture background. Bright-field and energy-loss images of the larger particles show a core-and-shell morphology, and the shells have a higher amount of high-O/Si domains as well as contaminating carbon compounds. On the other hand, the smaller particles (effective diameter = 36 nm) are also formed by distinct domains, but their morphology is neither spherical or core-and-shell. The mechanisms for particle formation presented in the literature are discussed, considering the present findings.
Subject: colloidal silica
transmission electron microscopy
energy-filtered imaging
silica particle microchemistry
Country: Brasil
Editor: Soc Brasileira Quimica
Rights: aberto
Identifier DOI: 10.1590/S0103-50532001000400013
Date Issue: 2001
Appears in Collections:Unicamp - Artigos e Outros Documentos

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