Revista mexicana de física
Print version ISSN 0035-001X
MORONTA, D; MARTIN-LANDROVE, M; GAGO, C and PARDEY, A.J. Proposition of two layered ionic structures, with xy disorder but z-ordered, in a quasi-liquid system. Rev. mex. fis. [online]. 2006, vol.52, suppl.3, pp. 208-210. ISSN 0035-001X.
Boundary layers at the liquid-solid interface of increasing concentrations of CuSO4 aqueous solutions in contact with glass have been studied. An orderly sequence of Cu2+ - SO24 - Cu2+- SO2-4 solvated ionic sub-layers parallel to the glass are formed, being the first one electrostatically anchored to the surface. Cu2+ EPR line intensity, and NMR proton relaxation T2 studies show outstanding similarities, which can be explained by the presence of different stages of ionic organization with the concentration, at the semi-liquid boundary layers. At a critical concentration Cm, two stable local layers (of two sub-layers each) of ions are proposed to be present. In them, the ions in the xy, parallel to the wall plane are randomly distributed, but with the proposed order in z perpendicular to the wall axis.
Keywords : Boundary layers; EPR; NMR; ionic order; magnetic ordering; CuSO4.