Electrostatics for Explorting the Nature of Water Adsorption on the Laponite Sheets' Surface
Entry by Haifei Zhang, AP 225, Fall 2009 (in progress ....)
Soft matter keywords
Water Adsorption, Laponite
In this paper, the authors studies the nature of the interaction of water with laponite surfaces using the topology of the electrostatic potential using density functional theory for periodic systems as well as an uncharged sheet model. The topological analysis predicts that for uncharged surfaces the adsorption mode is such that the water molecules are adsorbed almost parallel to the surface. For laponite surfaces, where there is a net charge, the adsorption mode involves electrostatic repulsion between the negative lone pairs on the water molecules and the ones on the surface oxygen atoms. As a consequence, the water molecules bind to the surface in a perpendicular and tilted approach, minimizing the repulsive interactions. The authors also discussed the advantage of using the topology of the electrostatic potential as an efficient method to describe the electrostatic interactions between adsorbates and surfaces.
 Electrostatics for Explorting the Nature of Water Adsorption on the Laponite Sheets' Surface Yosslen Aray, Manuel Marquez, Jesus Rodriguez, Santiago Coll, Yamil Simon-Manso, Carlos Gonzalez and David A. Weitz, J. Phys. Chem. 107, 8946-8952 (2003).