Hydrophobicity of talc basal surface

Abstract

The hydrophobicity of the talc basal surface is considered in the framework of the concept which relates the properties of layered silicates and their dispersions to the differences between the characteristics of the basal and side surfaces of their particles. The ab initio calculations of the energetics and geometry of the microclusters formed by water molecules adsorbed on the active sites (oxygen ions) located at the perfect basal surface of talc are performed. It is shown that the typical property of the hydrophobic surface is the adsorption of single molecules of water on extremely scarce or weak active sites of the surface, which act as secondary adsorption sites, and subsequent adsorption of water molecules on these secondary sites which results in the formation of ring-like structures. The heat of adsorption on this surface is shown to be essentially lower than the water condensation heat, which is also indicative of the hydrophobicity of the basal surface of talc.