A Study of the Structural Organization of Water and Aqueous Solutions by Means of Optical Microscopy

Abstract

The structural organization of water and aqueous solutions under an optical microscope in a layer with a thickness of 8 μm was investigated. It is shown that under room conditions water (including “ultrapure” water) and aqueous solutions are microdispersed systems. The revealed effect does not depend on the properties of the substrate (texture, hydrophilicity/hydrophobicity) and is an inherent property of the liquid. The disperse phase is based on contrasting micron-sized formations located in the center of low-contrast homogeneous spheres observed in a layer with a thickness of the order of the diameter of the observed structures. They form loose millimeter-sized associates in the liquid phase. When the water is boiled, the associates become disordered, but the dispersed phase is preserved. An increase in the ionic strength of the solution is accompanied by coacervation of the dispersed phase. When the liquid part of the water evaporates, the microdispersed phase remains on the substrate. The central particles begin to grow and take on the form of crystals. On the basis of the literature data and their own research, the authors believe that the structures are sodium chloride microcrystals surrounded by a thick layer of hydrated water. Possible ways of salt penetration into the aquatic environment are discussed.