title: Sub-diffusion and population dynamics of water confined in soft environments.
abstract: We have studied by using molecular dynamics computer simulations the dynamics of water confined in ionic surfactant phases, ranging from well ordered lamellar structures to micelles at low and high water loading, respectively. We have analysed in depth the main dynamical features in terms of mean-squared displacements and intermediate scattering functions, and found clear evidence of sub-diffusive behaviour. We have identified water molecules lying at the charged interface with the hydrophobic confining matrix as the main factor responsible for this unusual feature, and given a comprehensive picture of dynamics based on a very precise analysis of lifetimes at the interface. We conclude by providing, for the first time to our knowledge, a unique framework for rationalizing the existence of important dynamical heterogeneities in fluids adsorbed in soft confining environments.
authors.affiliation: Institut Laue-Langevin, 71 Avenue des Martyrs, CS 20156, 38042 Grenoble Cedex 9, France. hanot@ill.fr.
authors.forename: Samuel
authors.initials: S
authors.lastname: Hanot
authors.affiliation: Univ. Grenoble Alpes, INAC-SPRAM, F-38000 Grenoble, France. sandrine.lyonnard@cea.fr stefano.mossa@cea.fr and CNRS, INAC-SPRAM, F-38000 Grenoble, France and CEA, INAC-SPRAM, F-38000 Grenoble, France. stefano.mossa@cea.fr.
authors.forename: Sandrine
authors.initials: S
authors.lastname: Lyonnard
authors.affiliation: Univ. Grenoble Alpes, INAC-SPRAM, F-38000 Grenoble, France. sandrine.lyonnard@cea.fr stefano.mossa@cea.fr and CNRS, INAC-SPRAM, F-38000 Grenoble, France and CEA, INAC-SPRAM, F-38000 Grenoble, France. stefano.mossa@cea.fr.
authors.forename: Stefano
authors.initials: S
authors.lastname: Mossa