Author/Editor		Kralj-Iglič, V; Iglič, A
Title		Influence of finite size of ions on electrostatic properties of electric double layer
Type		članek
Source		Elektroteh Vestn
Vol. and No.		Letnik 61, št. 3
Publication year		1994
Volume		str. 127-33
Language		eng
Abstract		The electric double layer is formed when a charged plane is placed in contact with an electrolyte solution. The ions which are oppositely charged than the plane are attracted by the plane and therefore accomulate near it, while the ions which carry the charge of equal sign as the plane are repelled by the plane and therefore expelled from its vicinity. In this work, some electrostatic properties of the electric double layer are considered. The electrostatic interaction of ions with the mean electric field is taken into account. The finite size of ions and water molecules is considered by means of volume exclusion principle. Starting from the statistical mechanical description, a procedure is proposed in which self consistent expressions for the free energy of the system, ion and water distribution functions and the differential equation for the electric field are derived. It is shown that the classical Gouy-Chapman model of the electric double layer which considers ions and water molecules as dimensionless is a good approximation only for low values of the surface charge density of the charged plane. When the values of the surface charge density are higher the finite size of ions should be considered. The expressions for the ion and water molecules distribution functions and the electric field which are presented here can be due to their simple form used for fitting different experimental data in electrochemistry and physics of biological membranes.
Descriptors		IONS ELECTRIC CONDUCTIVITY ELECTROLYTES MEMBRANES