Ion-Size Effect at the Surface of a Silica Hydrosol

Abstract

The author used synchrotron x-ray reflectivity to study the ion-size effect for alkali ions (Na${}^{+}$, K${}^{+}$, Rb${}^{+}$, and Cs${}^{+}$), with densities as high as $4\times 10^{18}-7\times 10^{18}$ m${}^{-2}$, suspended above the surface of a colloidal solution of silica nanoparticles in the field generated by the surface electric-double layer. According to the data, large alkali ions preferentially accumulate at the sol's surface replacing smaller ions, a finding that qualitatively agrees with the dependence of the Kharkats-Ulstrup single-ion electrostatic free energy on the ion's radius.

17 pages, 4 figures

References in corpus (6)

• Direct observation of charge inversion by multivalent ions as a universal electrostatic phenomenon
• Interfacial Tension of Electrolyte Solutions
• Monovalent counterion distributions at highly charged water interfaces: Proton-transfer and Poisson-Boltzmann theory
• Compact Layer of Alkali Ions at the Surface of Colloidal Silica
• X-ray study of the electric double layer at the n-hexane/nanocolloidal silica interface
• Crystals of Na+ ions at the surface of a silica hydrosol

Cited by in corpus (7)

• Multilayer of Phospholipid Membranes on a Hydrosol Substrate
• Kinetics of the Phospholipid Multilayer Formation at the Surface of the Silica Sol
• Study of DMPS Monolayers on a Water Substrate with Laboratory X-ray Reflectometer
• Modelless X-Ray Scattering Study of a Silica Hydrosol Surface
• Synchrotron X-Ray Reflectivity Study of the Adsorption Film of Octadecanamide at the Toluene-Water Interface
• On the Diffuse Structure of the Toluene - Water Interface
• Solid-Liquid Phase Transition in the Octadecanoic Acid Film Adsorbed on the Toluene-Water Interface