Mesostructured silica aerosol particles: comparison of gas-phase and powder deposit X-ray diffraction data.
Langmuir
; 27(9): 5542-8, 2011 May 03.
Article
em En
| MEDLINE
| ID: mdl-21466238
ABSTRACT
We report on the characterization of mesostructured aerosol silica particles in the gas phase using in situ synchrotron small-angle X-ray scattering (SAXS) in order to unveil the influence of the basic production parameters. The investigated system was based on tetraethylorthosilicate (TEOS) as the inorganic precursor and on cetyltrimethyl-ammonium bromide (CTAB) as the surfactant. The heating temperature, surfactant to silicate ratio, and particle flow rate were thoroughly investigated, and for this purpose, an in-house-built aerosol reactor equipped with a special X-ray observation chamber was used. Complementary fine structural analysis was applied on dried deposits of the silica aerosols comprising direct Fourier transforms as well as simple two-phase model fits. This resulted in robust estimates for the silica wall thickness and surfactant core radius of the hexagonally ordered mesostructure. The particle shape and size distribution were examined by scanning electron microscopy (SEM). The quality of the inner nanostructure was revealed from an analysis of the peak width. The comparison of data from the gas phase and powder deposit shows that, in general, slower drying conditions (heating temperature about 80 °C) and a medium surfactant to Si ratio (about 0.14) lead to nanostructures of the best quality in terms of well-defined long-range organization.
Texto completo:
1
Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Difração de Raios X
/
Dióxido de Silício
/
Gases
Idioma:
En
Revista:
Langmuir
Assunto da revista:
QUIMICA
Ano de publicação:
2011
Tipo de documento:
Article
País de afiliação:
Áustria