Wetting and dewetting of smooth, homogeneous, inert solid surfaces by simple liquids is relatively well understood. In contrast, our understanding of the wetting process of complex liquids or of micro-structured surfaces is still developing. This is despite the fact that wetting of complex liquids or complex surfaces is relevant in numerous processes – like printing, painting and coating, cleaning, oil recovery, flotation, or developing self-drying fabrics – and natural phenomena – like rain falling on plants and imbibing porous soils.
Complex liquids are liquids that are structured at different length scales, e.g. dispersions, polymer melts or solutions, emulsions, or dispersions. Complex surfaces include solid substrates showing ordered or random topological patterns, chemical heterogeneities, or porosity with typical length scales in the micro- or nanometer range. Also, soluble, viscoelastic or porous surfaces belong to this class, as well as highly curved surfaces like microparticles.
During this presentation I will talk about different wetting scenarios where drops of macro, micro- and nanoscopic dimensions spread on hard, deformable, or soluble surfaces, and about the wetting of microparticles; I will address the different processes and time scales I envision playing a major role.




