کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
610897 | 880661 | 2008 | 14 صفحه PDF | دانلود رایگان |
![عکس صفحه اول مقاله: The dielectric response of a colloidal spheroid The dielectric response of a colloidal spheroid](/preview/png/610897.png)
In this article, we present a theory for the dielectric behavior of a colloidal spheroid, based on an improved version of a previously published analytical theory [C. Chassagne, D. Bedeaux, G.J.M. Koper, Physica A 317 (2003) 321–344]. The theory gives the dipolar coefficient of a dielectric spheroid in an electrolyte solution subjected to an oscillating electric field. In the special case of the sphere, this theory is shown to agree rather satisfactorily with the numerical solutions obtained by a code based on DeLacey and White's [E.H.B. DeLacey, L.R. White, J. Chem. Soc. Faraday Trans. 2 77 (1981) 2007] for all zeta potentials, frequencies and κa⩾1κa⩾1 where κ is the inverse of the Debye length and a is the radius of the sphere. Using the form of the analytical solution for a sphere we were able to derive a formula for the dipolar coefficient of a spheroid for all zeta potentials, frequencies and κa⩾1κa⩾1. The expression we find is simpler and has a more general validity than the analytical expression proposed by O'Brien and Ward [R.W. O'Brien, D.N. Ward, J. Colloid Interface Sci. 121 (1988) 402] which is valid for κa≫1κa≫1 and zero frequency.
We derived the dipolar coefficients βiβi for an ellipsoidal colloid as a function of the different complex conductivities (KiKi) and depolarization factors (LiLi).Figure optionsDownload as PowerPoint slide
Journal: Journal of Colloid and Interface Science - Volume 326, Issue 1, 1 October 2008, Pages 240–253