Author/Editor		Bohinc, Klemen
Title		Vpliv velikosti ionov na fizikalne lastnosti električne dvojne plasti
Type		monografija
Place		Ljubljana
Publisher		Fakulteta za elektrotehniko
Publication year		2001
Volume		str. 77
Language		slo
Abstract		The electric double layer is created by a charged surface in contact with electrolyte solution. The expression for the free energy of an electric double layer is derived using a simple statistical mechanical approach by the grand ensemble. The electrostatic interactions are considered by the mean electrostatic field while the finite size of particles constituing the electrolyte solution is considered by the excluded volume effect. For that, the particles in the solution are distributed over a lattice with an adjustable constant. Different sizes of the ions are described by the different values of the lattice constant. The free energy is derived for any composition of ions and any ion valencies that allows for vanishing mean electrostatic field far from the charged surface. Two geometries of the electric double layer are considered: planar and cylindrical. Thickness of the electric double layer is considered. Two measures are introduced that describe an effective thickness of the electric double layer: a distance where the density of the number of counterions drops for a chosen fraction of its maximal value and a distance defining a region that contains a chosen fraction of the excess of counterions. It is shown that the effective thickness of the electric double layer increases with increasing counterion size and with decreasing bulk concentration of ions while increasing the surface charge may cause both, a decrease or an increase of the effective thickness, depending on the size of the counterions. It is shown that the description of the effective thickness of the electric double layer by the Debye length dif%rs qualitatively from the presented description for low bulk concentration of ions. Counterion condensation can be roughly described as a feature where a certain fraction of the counterion excess is located near the charged plane. The counterion condensation in flat and in cylindrical electrical double layer is studied. (Abstract truncated at 2000 characters)
Descriptors		IONS ELECTROLYTES ELECTROSTATICS PARTICLE SIZE LIPID BILAYERS