Abstract
Different results from recent communications on the hydrodynamic characterization of ultrasonicated silica (®Aerosil) hydrosols led to a critical reappraisal of the data.
It can be concluded that the degree of dispersion achievable in pyrogenic (Aerosil) hydrosols by ultrasonication is highly sensitive to the detailed parameters of the dispersion process. Characterization in terms ofabsolute numbers of a limiting particle morphology, corresponding to minima of aggregate size, porosity and number of primary particles in the aggregate is not possible.
The most straightforward approach for hydrodynamic characterization seems to be a combination of sedimentation and diffusion data.
Other approaches using a combination of sedimentation and viscosity data underestimate the particle dimensions. Moreover, they are quite arbitrary since the final result depends upon the proper choice between several equations for fitting the viscosity concentration dependence; the most rigorous approach seems to be an extended Einstein equation which has recently been adapted to particle aggregates.
This is a preview of subscription content, log in via an institution to check access.
Similar content being viewed by others
Literature
Strenge K, Pilgrimm H (1983) The disaggregation of solid particle aggregates by ultrasonication, Colloid & Polymer Sci 261:855
Strenge K (1978) Zur Bestimmung der Dicke immobiler Wasserschichten auf SiO2-OberflÄchen mit Hilfe der relativen ViskositÄt verdünnter Suspensionen, Z phys Chemie, Leipzig 259:102
Eisenlauer J (1978) Der Einflu\ von Polymeradsorption auf die StabilitÄt kolloidaler Dispersionen, Ph D Thesis, Technische UniversitÄt München (1978)
Eisenlauer J, Killmann E (1980) Stability of Colloidal Silica (Aerosil) Hydrosols I Preparation and characterization of Silica (Aerosil) Hydrosols, J Colloid Interface Sci 74:108
Killmann E, Eisenlauer J, Kaniut P (1979) Charakterisierung von Silika (Aerosil) Hydrosolen durch Photonenkorrelationsspektroskopie, Z. Naturforsch 34a:68
Gillespie T (1976) (ed) Kerker M, in Colloid and Interface Sci Vol IV: Hydrosols and Rheology, Academic Press, New York, p 465
Gillespie T (1983) The Effect of Aggregation and Particle Size Distribution on the Viscosity of Newtownian Suspensions, J Colloid Interface Sci 94:166
Auweter H, Unterforsthuber K, Horn D (1983) Teilchengrö\enanalyse kolloiddisperser Systeme durch Photonenkorrelationsspektroskopie, 31. Hauptversammlung der Kolloidgesellschaft e. V., Bayreuth, detailed publication is in preparation
Elias HG (1981) Makromoleküle, Hüthig & Wepf, Heidelberg, 4. Auflage p 259:318
Eisenlauer J, Korn M, Killmann E (1980) Stability of Colloidal Silica (Aerosil) Hydrosols, II Influence of the pH Value and the Adsorption of Polyethyleneglycols, J Colloid Interface Sci, 74:120
Happel J (1957) Viscosity of Suspensions of Uniform Spheres J Appl Physics 28:1288
Mewis J, Spaull AJB (1976) Rheology of Concentrated Dispersions, Adv. Colloid Interface Sci 6:173
Author information
Authors and Affiliations
Rights and permissions
About this article
Cite this article
Eisenlauer, J. A critical reappraisal of recent communications on the hydrodynamic characterization of silica (aerosil) hydrosols. Colloid & Polymer Sci 262, 906–910 (1984). https://doi.org/10.1007/BF01452223
Received:
Accepted:
Issue Date:
DOI: https://doi.org/10.1007/BF01452223