Osmotic Blistering - Coatings Under Pressure

Paint application over soluble salt contamination can promote osmotic blistering failure of a coating as can certain problematic application conditions such as over-thinning or excessive film build, which can result in the retention of hydrophilic paint solvents.  Osmotic blistering is a common failure mode for coatings in wet service environments but the basic chemistry and physics of osmotic pressure is generally explained improperly in the protective coatings literature.  A better understanding of the nature of osmotic pressure should change the way we deal with the threat of osmotic blistering failure.