The trend towards water-borne systems is unbroken, but they can be mimosas compared to their solvent-borne predecessors. Rheology is different and also the surface energy. The latter can lead to problems in leveling and substrate wetting. Nobody likes to see brush stripes, or overspray drops in the surface. The basis for both effects is mainly surface energy. The surface energy of water is much higher, leading to issues in spreading, specially on low energy and non-polar surfaces. Fluor-based additives are very effective to reduce the surface tension of water-borne coatings, up to the point, to overcorrection at very low dosages, ...