Confined space effects driving to heterogenization of solutions at the interfaces

Abstract

Water and concentrated solutions of acids (HCl, H3PO4, and H3PO3) or H2O2 are clustered at the interfaces of nanosilicas and multi-layer graphene oxide (MLGO) as shown by low-temperature 1H NMR spectroscopy. The acid solutions in contact with silica or MLGO powders placed in nonpolar (CCl4) or weakly polar (CDCl3) media form nanodomains and clusters of several types and sizes with different contents of water and solutes. This differentiation of the solutions is stronger at a surface of more compacted nanosilicas because of enhanced confinement effects in narrower pores (voids) between adjacent nanoparticles. For MLGO, the confined space effects are relatively weak but the formation of ice crystallites during freezing of the suspension changes the material texture. Obtained results are of importance for deeper insight into the mechanism of the interfacial behavior of complex solutions under different confined space effects and due to the influence of organic co-solvents.