A Study of Colloidal Particle Brownian Aggregation by Light Scattering Techniques

Aggregation kinetics and aggregate structure are studied for monodisperse polystyrene latex particles of diameter 60 and 140 nm. The experimental part consists of measurements over a rather broad range of electrolyte concentrations (0.1 to 0.8MNaCl) and for particle volume fractions 10−6to 10−5, usi...

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Bibliographic Details
Published in:Journal of colloid and interface science 1997-11, Vol.195 (2), p.299-306
Main Authors: Kyriakidis, Athanasios S., Yiantsios, Stergios G., Karabelas, Anastasios J.
Format: Article
Language:English
Subjects:
Brownian aggregation
Chemistry
colloidal fractals
Colloidal state and disperse state
Exact sciences and technology
General and physical chemistry
light scattering
Physical and chemical studies. Granulometry. Electrokinetic phenomena
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Summary:Aggregation kinetics and aggregate structure are studied for monodisperse polystyrene latex particles of diameter 60 and 140 nm. The experimental part consists of measurements over a rather broad range of electrolyte concentrations (0.1 to 0.8MNaCl) and for particle volume fractions 10−6to 10−5, using dynamic and static light scattering techniques. The aggregation kinetics data obtained can be fitted into a single curve with a proper scaling of time and size for both particle sizes. For relatively long times, we observe power-law type kinetics, characteristic of diffusion limited aggregation (DLA). Fractal dimensions in all cases are close to 1.7 (as expected for DLA). The light scattering behavior of aggregates of arbitrary size is also studied numerically by employing computer simulations, and existing models (Linet al.,1990.J. Colloid Interface Sci.137,263) are tested and improved for certain conditions (large angles and/or large particles). The shape of the experimental kinetics curves is successfully described with numerical simulations, further suggesting that (under the conditions tested) DLA aggregation prevails for short times as well.
ISSN:0021-9797
1095-7103
DOI:10.1006/jcis.1997.5150