Modelling capillary phenomena at a mesoscale: From simple to complex fluids

A mesoscopic model for studying capillary phenomena is introduced. The fluid is represented by particles interacting through soft forces that allow condensation. A model for a solid wall is also presented whose affinity for the liquid can be tuned from hydrophilic to superhydrophobic. Regarding the dynamics, the validity of the model was assessed studying the classical drop spreading on a wetting substrate where good agreement was found with the scaling predicted theoretically. We show also how to extend the proposed model to deal with symmetrical binary mixtures. This model opens the way to model capillary phenomena involving complex fluids.