title: Role of stringlike, supramolecular assemblies in reentrant supernematic liquid crystals.
abstract: Using a combination of isothermal-isobaric Monte Carlo and microcanonical molecular dynamics we investigate the relation between structure and self-diffusion in various phases of a model liquid crystal using the Gay-Berne-Kihara potential. These molecules are confined to a mesoscopic slit pore with atomically smooth substrate surfaces. As reported recently [seeM. G. Mazza et al., Phys. Rev. Lett. 105, 227802 (2010)], a reentrant nematic (RN) phase may form at sufficiently high pressures and densities. This phase is characterized by a high degree of nematic order and a substantially enhanced self-diffusivity in the direction of the director n that exceeds that of the lower-density nematic and an intermittent smectic-A phase by about an order of magnitude. Here we demonstrate that the unique transport behavior in the RN phase may be linked to a confinement-induced packing effect that causes the formation of supramolecular, stringlike conformations. The strings consist of several molecules traveling in the direction of n as individual "trains" consisting of chains of molecular "cars."
authors: Stranski-Laboratorium für Physikalische und Theoretische Chemie, Technische Universität Berlin, Berlin, Germany.
authors: Marco G
authors: MG
authors: Mazza
authors: Manuel
authors: M
authors: Greschek
authors: Rustem
authors: R
authors: Valiullin
authors: Martin
authors: M
authors: Schoen
mesh_terms: D050866:Liquid Crystals / Q000737:chemistry*; D056004:Molecular Dynamics Simulation; D011336:Probability