Original scientific paper

Fractal Structures and Their Effects on the Dynamics of Supramolecular Aggregates Studied by Light and Thermodynamic Measurements

Francesco Mallamace ; Dipartimento di Fisica dell’Universita’ di Messina, 1-98166, Vill. S. Agata C.P. 55 (Messina) Italy
Norberto Micali ; Istituto di Tecniche Spettroscopiche del C.N.R., 1-98166, Vill. S. Agata (Messina) Italy

Abstract

We report a review on light scattering, viscosity, sound propagation and calorimetric data in aggregating disperse systems, i.e. colloidal suspensions of polystyrene latex spheres and water in oil microemulsions. By elastic (intensity) and quasielastic light scattering (dynamics) direct information is obtained on aggregated clusters being built with a fractal structure and on the corresponding different kinetic mechanisms. In particular, dynamic data, showing a well-defined sealing behaviour in the measured mean linewidth, confirm the picture proposed by intensity data and allow a rough estimate of the cluster dimension. All the thermodynamic data, discussed in terms of a two- fluid model (suspending fluid and disperse interacting system), give evidence of the main role played by the attractive interparticle interaction.
In fact, the typical features observed in viscosity and specific heat data and in the viscoelastic behaviour shown by these disperse systems can be connected to the long range structural order built by fractal aggregation processes. All the experimental data are consistent with the Derjaguin-Landau-Ver- wey-Overbeek theory on colloidal stability.

Keywords

Hrčak ID:

137181

URI

https://hrcak.srce.hr/137181

Publication date:

15.8.1992.

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