Formation of hydrate films on the surface of calcium silicate and aluminate in the presence of polyelectrolytes

Abstract

To elucidate the mechanism of moistening and overmoistening of soils and mineral soil components capable of chemical hydration, the sorption of water vapor has been studied in combination with synchronous conductometric measurements. Effect of organic polyelectrolyte molecules on the hydration kinetics and the formation of hydrate films on their surface has been revealed for dehydrated calcium silicate and aluminate simulating minor soil components. The plotting of sorption–desorption curves has shown that hydrate–polymer films formed by aliphatic or aromatic polyelectrolytes with different functional groups (–COOH,–OH,–NH₂,–CONH, etc.) significantly vary in dispersion and structure. The changes in dispersion during hydration are frequently not correlated with the amount of resulting hydrates, the content of which is controlled by the crystallochemical features of sorbents, the structure and activity of the polymer functional groups, and the conditions of sorption kinetic studies. It has been shown that the formation of low-permeable surface organomineral layers is typical for aliphatic polyelectrolytes, while more permeable layers determining the water-physical and structure-forming properties of soils are typical for aromatic polyelectrolytes.