title: Evolution of a rare sequence of surface transitions with temperature and film thickness.
abstract: In free-standing smectic films, layers near the surfaces of the film often contain molecules tilted away from the layer normal, while in the bulk of the film the magnitude of the tilt decays exponentially with distance from the surface. We have identified the detailed molecular tilt orientations in the surface layers of films for one antiferroelectric liquid crystal compound. A series of five surface structures exists with different nonplanar tilt arrangements for each structure. The molecular orientations in the surface layers evolve with temperature. The polarization of the film also evolves with temperature, corresponding to the tilt arrangements. Using ellipsometric data, we reconstruct the changes in the magnitude and azimuthal direction of the tilt as functions of temperature. We have also studied films of several different thicknesses. We present a phase diagram for the five surface structures showing the dependence on temperature and film thickness.
authors.affiliation: School of Physics and Astronomy, University of Minnesota, Minneapolis, Minnesota 55455, USA.
authors.forename: B K
authors.initials: BK
authors.lastname: McCoy
authors.forename: LiDong
authors.initials: L
authors.lastname: Pan
authors.forename: Z Q
authors.initials: ZQ
authors.lastname: Liu
authors.forename: S T
authors.initials: ST
authors.lastname: Wang
authors.forename: Shun
authors.initials: S
authors.lastname: Wang
authors.forename: J W
authors.initials: JW
authors.lastname: Goodby
authors.forename: C C
authors.initials: CC
authors.lastname: Huang
mesh_terms: D003198:Computer Simulation; D050866:Liquid Crystals / Q000737:chemistry*; D008567:Membranes, Artificial; D008956:Models, Chemical; D044367:Phase Transition; D013499:Surface Properties; D013696:Temperature
chemical_list: D008567:Membranes, Artificial