2002/10/21 by Emmanuel Trizac, Miguel Aubouy, Lydéric Bocquet +1 · 2 citations
Chemistry · Engineering · Materials Science · Physics and Astronomy · #Electrostatics and Colloid Interactions #Material Dynamics and Properties #Microfluidic and Bio-sensing Technologies #cond-mat.soft
paper · pdf · doi:10.1088/0953-8984/15/1/339
published as J. Phys: Condens. Matt. 15, S291 (2003). · 5 pages, 2 figures, to appear in Journal of Physics : Condensed Matter
arxiv created 2002/10/21 · openalex publication_date 2002/12/13 · arxiv updated 2009/11/30 · openalex created_date 2016/06/24 · openalex updated_date 2026/08/04
We propose a simple approximation scheme for computing the effective charges of highly charged colloids (spherical or cylindrical with infinite length). Within non-linear Poisson–Boltzmann theory, we start from an expression for the effective charge in the infinite-dilution limit which is asymptotically valid for large salt concentrations; this result is then extended to finite colloidal concentration, approximating the salt partitioning effect which relates the salt content in the suspension to that of a dialysing reservoir. This leads to an analytical expression for the effective charge as a function of colloid volume fraction and salt concentration. These results compare favourably with the effective charges at saturation (i.e. in the limit of large bare charge) computed numerically following the standard prescription proposed by Alexander et al within the cell model.