Approximate Analytic Expression for the Electrophoretic Mobility of a Spherical Colloidal Particle.
An approximate analytic expression for the electrophoretic mobility of a spherical colloidal particle in a symmetrical electrolyte solution is obtained. This mobility expression, which is correct to the order of the third power of the zeta-potential of the particle, considerably improves Henry's mobility formula (Proc. R. Soc. London Ser. A 133, 106 (1931)) and has a much simpler form than similar mobility formulas expressed in powers of zeta derived by Overbeek (Kolloid-Beihefte 54, 287 (1943)) and by Booth (Proc. R. Soc. London Ser. A 203, 514 (1950)). Comparison with the exact computer calculation by O'Brien and White (J. Chem. Soc. Faraday Trans. 2 74, 1607 (1978)) shows that the obtained mobility formula is an excellent approximation, especially for small kappaa (where kappa is the Debye-Hückel parameter and a is theparticle radius) in which region no other simple analytic mobility formulas are available than Henry's formula, which is correct to order zeta and is applicable only for low zeta. Copyright 2001 Academic Press.
Ohshima
Hiroyuki
H
Faculty of Pharmaceutical Sciences and Institute of Colloid and Interface Science, Science University of Tokyo, 12 Ichigaya Funagawara-machi, Shinjuku-ku, Tokyo, 162-0862, Japan