20.500.12556/RUL-134268 Electric double layer and orientational ordering of water dipoles in narrow channels within a modified Langevin Poisson-Boltzmann model The electric double layer (EDL) is an important phenomenon that arises in systems where a charged surface comes into contact with an electrolyte solution. In this work we describe the generalization of classic Poisson-Boltzmann (PB) theory for point-like ions by taking into account orientational ordering of water molecules. The modified Langevin Poisson-Boltzmann (LPB) model of EDL is derived by minimizing the corresponding Helmholtz free energy functional, which includes also orientational entropy contribution of water dipoles. The formation of EDL is important in many artificial and biological systems bound by a cylindrical geometry. We therefore numerically solve the modified LPB equation in cylindrical coordinates, determining the spatial dependencies of electric potential, relative permittivity and average orientations of water dipoles within charged tubes of different radii. Results show that for tubes of a large radius, macroscopic (net) volume charge density of coions and counterions is zero at the geometrical axis. This is attributed to effective electrolyte charge screening in the vicinity of the inner charged surface of the tube. For tubes of small radii, the screening region extends into the whole inner space of the tube, leading to non-zero net volume charge density and non-zero orientational ordering of water dipoles near the axis. electric double layer orientational ordering of water dipoles Helmholtz free energy modified Langevin Poisson-Boltzmann model električni dvojni sloj orientacijsko urejanje vodnih dipolov Helmholtzeva prosta energija evolucijski modificiran Langevin Poisson-Boltzmannov model true false true Angleški jezik Slovenski jezik Članek v reviji 2022-01-04 10:21:46 2022-01-04 10:21:47 2022-09-13 03:54:18 0000-00-00 00:00:00 2020 0 0 19 str. iss. 9, art. 1054 Vol. 22 Sep. 2020 0000-00-00 Zaloznikova Objavljeno NiDoloceno 0000-00-00 0000-00-00 0000-00-00 577 1099-4300 10.3390/e22091054 30268931 RAZ_Drab_Mitja_2020.pdf RAZ_Drab_Mitja_2020.pdf 1 725A562708C6EC95522CB7076F299FFC b772cf67774b1ee42f12de476064f3fe9ead2769700a6c15708d73c8e0a77778 f16e643d-6d3f-11ec-abdb-00155dcfd717 https://repozitorij.uni-lj.si/Dokument.php?lang=slv&id=152634 https://www.mdpi.com/1099-4300/22/9/1054 1 93a5402f-6d3f-11ec-abdb-00155dcfd717 https://repozitorij.uni-lj.si/Dokument.php?lang=slv&id=152633 Fakulteta za elektrotehniko Zdravstvena fakulteta 0 0 0