Ion size effects on the streaming potential of narrow charged pores

The effects of ion size on the streaming potential of fixed charge membrane s with narrow pores are studied theoretically as a function of the ratio be tween the ionic and the pore radii, and the ratio between the external conc entration acid the membrane fixed charge concentration. To this end, the ra dial distributions of the ionic concentrations, space charge density, press ure and electric potential are obtained for finite size and point ions usin g a generalised Poisson-Boltzmann equation. It is found that the streaming potential increases significantly with increasing ion size. The results are presented in terms of experimentally controlled parameters in order to sti mulate targeted experimental work with well defined ionic species and membr anes.