High-pressure liquid dispersion and fragmentation of flame-made silica agglomerates.

Wengeler R, Teleki A, Vetter M, Pratsinis SE, Nirschl H

Langmuir 22 (11) 4928-4935 [2006-05-23; online 2006-05-17]

The influence of primary particle diameter and the degree of agglomeration of flame-made silica agglomerate suspensions in aqueous solutions is studied by high-pressure dispersion (up to 1500 bar) through a nozzle with a 125 microm inner diameter. These particles were produced (4-15 g/h) by oxidation of hexamethyldisiloxane (HMDSO) in a coflow diffusion flame reactor. Their average primary particle size (10-50 nm) and degree of agglomeration were controlled by varying the oxygen and precursor flow rates. The particles were characterized by nitrogen adsorption, electron microscopy, and small-angle X-ray scattering. Hydrodynamic stresses break up soft agglomerates and yield hard agglomerate sizes in the range of 100-180 nm, as characterized by dynamic light scattering. Soft agglomerates exhibited decreasing light scattering diameters with increasing dispersion pressure, while hard agglomerates were insensitive.

Alexandra Teleki

QC bibliography QC xrefs

PubMed 16700577

DOI 10.1021/la053283n

Crossref 10.1021/la053283n