Surroundings effects on the interfacial and temperature behaviors of NaOH/water bound to hydrophilic and hydrophobic nanosilicas.

It has been shown that bound water and water/NaOH represent various clusters and domains whose characteristics depend strongly on nanosilica hydrophilicity/hydrophobicity, dispersion media (air, CDCl, DMSO, CDCl/DMSO), subsequent or simultaneous deposition of NaOH and water, and temperature. Water amount (0.1 g/g) was selected too small to completely dissolve NaOH (0.1 g/g) under confined space effects and low temperatures. Chaotropic hydrophobic AM1 and CDCl enhance water clusterization and HBN disorder (weakly associated water, WAW appears) in contrast to kosmotropic hydrophilic A-300, NaOH, and DMSO reducing the clusterization and HBN disorder in bound water (WAW disappears). Several aspects related to the interfacial and temperature behaviors of water and co-adsorbates bound to the nanosilicas were elucidated.