title: Entropy-driven enhanced self-diffusion in confined reentrant supernematics.
abstract: We present a molecular dynamics study of reentrant nematic phases using the Gay-Berne-Kihara model of a liquid crystal in nanoconfinement. At densities above those characteristic of smectic A phases, reentrant nematic phases form that are characterized by a large value of the nematic order parameter S≃1. Along the nematic director these "supernematic" phases exhibit a remarkably high self-diffusivity, which exceeds that for ordinary, lower-density nematic phases by an order of magnitude. Enhancement of self-diffusivity is attributed to a decrease of rotational configurational entropy in confinement. Recent developments in the pulsed field gradient NMR technique are shown to provide favorable conditions for an experimental confirmation of our simulations.
authors.affiliation: Stranski-Laboratorium für Physikalische und Theoretische Chemie, Technische Universität Berlin, Straße des 17. Juni 135, 10623 Berlin, Germany.
authors.forename: Marco G
authors.initials: MG
authors.lastname: Mazza
authors.forename: Manuel
authors.initials: M
authors.lastname: Greschek
authors.forename: Rustem
authors.initials: R
authors.lastname: Valiullin
authors.forename: Jörg
authors.initials: J
authors.lastname: Kärger
authors.forename: Martin
authors.initials: M
authors.lastname: Schoen