  We present the advantages of a multiscale modelling strategy for the
understanding of systems with charged interfaces. On the one hand, one can
simulate a complex system at different levels, depending on the relevant length
and time scales for a given physical chemistry problem. On the other hand, one
should make the link between the various levels of description, e.g. following
a bottom-up approach. We illustrate here the case of charged porous materials,
in particular clay minerals, by discussing physical chemistry issues that arise
in the context of geological disposal of nuclear wastes and CO2 sequestration.
