Derjaguin’s Water II: a surface hydration phenomenon

B.V. Derjaguin’s promotion of anomalous water II (polywater) in the early 1970s was an embarrassing point in the career of an illustrious chemist, and quickly repudiated by Derjaguin himself. Water II does not exist as a bulk liquid. And yet a theoretical model of the hydration of ions developed by I. Klugman, consistent with electrolyte properties such as equivalent conductivity, diffusion coefficient, and viscosity, found a density of water molecules in the hydration shell of ions to be 1.4 g/cm³, close to the density of water II reported by Derjaguin and Churaev. Given Derjaguin and Churaev’s use of adsorption in fine capillaries, Klugman postulates that their anomalous experiments can be understood as measuring the hydration layer of adsorbed water rather than bulk water. Derjaguin’s last publication in 1994 on violation of Archimedes’ Law during adsorption may be intended to hint at this conclusion. Perhaps Derjaguin’s involvement with water II can, in the end, be celebrated not as a study of bulk liquid but as a study of adsorption phenomena and hydration.