title: Superpermittivity of nanoconfined water.
abstract: Nowadays, it is well established that the physical properties of confined liquids strongly differ from those in bulk phase. While dynamical and structural properties were strongly explored, dielectric properties are poorly studied despite their importance in the understanding and the modelling of molecular mechanism in a number of nano-applications such as nanofluidics, nanofiltration, and nanomedicine. Among them, the dielectric permittivity is probably one of the most important. The lack of knowledge about it strongly limits our ability to model fluid-material interactions and more generally our understanding of the behaviour of confined fluids. Recently, the dielectric permittivity of confined water in silica, Metal Organic Frameworks, and graphene materials was found to be slightly higher than the permittivity of water in bulk phase. In this work, the permittivity of water and dichloromethane confined in carbon nanotubes was predicted by means of molecular dynamics simulations. The static dielectric constant was found to be 700, i.e., 10-fold higher than the bulk value. This superpermittivity has, for origin, the excluded volume and the presence of an unconfined direction leading to a pre-orientation of water molecules close to the pore wall and an increase in dipolar fluctuations.
authors.affiliation: Institut des Sciences Chimiques de Rennes, CNRS, UMR 6226, Université de Rennes 1, 263 Avenue du Général Leclerc, 35042 Rennes, France.
authors.forename: Richard
authors.initials: R
authors.lastname: Renou
authors.affiliation: Institut des Sciences Chimiques de Rennes, CNRS, UMR 6226, Université de Rennes 1, 263 Avenue du Général Leclerc, 35042 Rennes, France.
authors.forename: Anthony
authors.initials: A
authors.lastname: Szymczyk
authors.affiliation: Institut Charles Gerhardt Montpellier UMR 5253 CNRS UM2, UM1, Université Montpellier 2, Place E. Bataillon, 34095 Montpellier Cedex 05, France.
authors.forename: Guillaume
authors.initials: G
authors.lastname: Maurin
authors.affiliation: Institut de Chimie de Clermont-Ferrand, ICCF, UMR CNRS 6296, BP 10448, F-63000 Clermont-Ferrand, France.
authors.forename: Patrice
authors.initials: P
authors.lastname: Malfreyt
authors.affiliation: Institut de Physique de Rennes, IPR, UMR CNRS 6251, 263 Avenue du Général Leclerc, 35042 Rennes, France.
authors.forename: Aziz
authors.initials: A
authors.lastname: Ghoufi