Water Clusterization in the Interparticle Space of Hydrophobic Nanosilica АМ-1

Abstract

The processes occurring in hydrated powders and concentrated suspensions of hydrophobic silica were studied by 1H NMR spectroscopy. It is shown that a mixture of methyl silica and water with a hydration of less than 1 g / g is a wet powder, where water is in the form of submicron clusters filling the interparticle voids of nanosilica, and the interfacial energy is directly proportional to the amount of added water. It was found that at high water concentrations there is a spontaneous increase in the size of water structures, which is accompanied by a sharp decrease in interfacial energy, that may reflect the disappearance of narrow interparticle voids or their filling with air. It is shown that aqueous suspensions of AM-1 are easily mixed with a weakly polar organic solvent chloroform, forming a stable suspension with close the amounts both of water and chloroform. It was revealed that the aqueous suspension of methyl silica has high thixotropic properties, which depend on the time and the magnitude of the applied mechanical loads.

Keywords

• 1h nmr spectroscopy
• hydrophobic silica
• thixotropy
• mechanical loads