  We study the electrophoretic mobility of spherical particles and the
electrical conductivity in salt-free concentrated suspensions including finite
ion size effects. An ideal salt-free suspension is composed of just charged
colloidal particles and the added counterions that counterbalance their surface
charge. In a very recent paper [Roa et al., Phys. Chem. Chem. Phys., 2011, 13,
3960- 3968] we presented a model for the equilibrium electric double layer for
this kind of suspensions considering the size of the counterions, and now we
extend this work to analyze the response of the suspension under a static
external electric field. The numerical results show the high importance of such
corrections for moderate to high particle charges, especially when a region of
closest approach of the counterions to the particle surface is considered. The
present work sets the basis for further theoretical models with finite ion size
corrections, concerning particularly the ac electrokinetics and rheology of
such systems.

Soft Condensed Matter