Surface Properties of Vitally Important Ions: Sessile Desiccated Drop Studies

Surface properties of ions in a liquid media are the most important and interesting topic of physical-chemical research. Complex approaches with using a lot of modern equipment are used for study this problem. Here we demonstrate a distinctive method, which is based on self-organizing processes in sessile desiccative drops of water salt solutions. The features of crystallization of aqueous solutions of KCl, NaCl, CaCl2 and MgCl2, as well as of their mixtures drying in the form of drops (3 ul) on glass have been studied by optical microscopy and acoustic impedancemetry. “Dynamic portraits” of crystallization kinetics (KCl, NaCl and their mixture) or of saline condensation (CaCl2 and MgCl2) in the course of drop drying have been obtained for each sample. The phenomenon of drop fragmentation of a mixture of potassium-containing solutions of various chlorides and formation of individual 3D structures on the glass has been revealed. The mechanisms of formation of such structures associated with different surface activity of the studied ions are considered. It is demonstrated that the used approaches are promising for obtaining additional information about complex behavior of ions in aqueous media.