Polydispersity During the Formation and Growth of the Stober Silica Particles from Small-Angle X-Ray Scattering Measurements

Published

September 1, 2000

Author(s)

H Boukari, Gabrielle G. Long, M T. Harris

Abstract

The early stages of formation of Stober silica particles have been investigated in situ during the hydrolysis and condensation of tetraethylorthosilicate under base-ammonia conditions in different alcoholic solvents. Time=resolved ultra small-angle X-ray scattering by the entities produced in the solutions is used for structural characterization and monitoring of the growth kinetics of the particles. Our primary focus is to assess the polydispersity of the formed colloidal particles and its evolution as a function of time. We first applied a maximum entropy analysis of the scattering data to determine the size distribution and the time-evolution of the size distribution of the colloidal particles. Second, we extended the cumulant method to analyze our earlier small-angle X-ray scattering data described in (J. Colloid Interface Sci. 1997. 194. 311, and Chem. Meter. 1997.9, 2376) and search for the presence of a distribution of fractal particles. The maximum entropy analysis indicates that there is a continuous nucleation of particles during the synthesis, and that this takes place within a relatively narrow size distribution. The cumulant analysis shows that, except at later times, the data are not adequate to confirm conclusively the presence of a distribution of fractal dimension at any time during the experiment. We discuss the impact of these results on growth kinetic models proposed for this system.

Citation

Journal of Colloid and Interface Science

Volume

229

Issue

No. 1

Pub Type

Journals

Keywords

nucleation, SAXS, small-angle x-ray, stober particles, USAXS

Citation

Boukari, H. , Long, G. and Harris, M. (2000), Polydispersity During the Formation and Growth of the Stober Silica Particles from Small-Angle X-Ray Scattering Measurements, Journal of Colloid and Interface Science (Accessed May 4, 2024)