In this work, we discuss the role that particle size plays in the manifestations of surface conduction on the dielectric response of colloidal dispersions. To that aim, experimental data on the dielectric constant of polystyrene suspensions of two different particle diameters (23 and 530 nm) are fir
Numerical Results for the Dielectric Dispersion Parameters of Colloidal Suspensions
β Scribed by C. Grosse; F.J. Arroyo; V.N. Shilov; A.V. Delgado
- Publisher
- Elsevier Science
- Year
- 2001
- Tongue
- English
- Weight
- 227 KB
- Volume
- 242
- Category
- Article
- ISSN
- 0021-9797
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β¦ Synopsis
Numerical spectra for the dielectric relaxation of colloidal suspensions of latex particles in aqueous KCl electrolyte solutions at 25 β’ C were obtained over a wide range of conditions: 10 ΞΆ potential values evenly distributed between 20 and 200 mV, and 11 ΞΊa values evenly distributed in logarithmic scale between 1 and 100. The data were used to determine the parameter values that characterize both the low-and high-frequency microscopic (dipolar coefficient) and macroscopic (complex conductivity) dispersions. The presented results make it possible to directly compare experimental data for suspensions of particles having any size with numerical predictions, without having to compute the numerical spectra. They also permit us to precisely define the range of applicability of the theoretical expression of Shilov and Dukhin (Colloid J. 32, 245 (1970)) combined with that of O'Konski (J. Phys. Chem. 64, 605 (1960)) for the representation of the dielectric behavior of colloidal suspensions in a broad frequency range.
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In this article, a systematic numerical study is described of the effect of the polydispersity of suspensions of spherical particles on their dielectric behavior, in both the frequency and time domains, starting from the model proposed by DeLacey and White (J. Chem. Soc., Faraday Trans. 2 77, 2007 (
A new technique for the determination of reflection coefficients arising in dispersive systems is presented. The method makes use of cepstral analysis, which relies on a single measured signal. In earlier studies cepstral methods have been applied to reflection coefficient determination for non-disp