Nonuniversality in Imbibition

We report an imbibition experiment in 2D random porous media in which height - height correlation function grows with a nonuniversal exponent; rather it depends on evaporation. We present an imbibition model which is consistent with the experiment. It also takes account of the size of the diffusing particles and can easily be extended to study multicomponent systems. The model also shows self-organisation of the interface. To our knowledge this is the first model of imbibition which explicitly allows for evaporation.