title: Effect of smectic short-range order on the discontinuous anchoring transition in nematic liquid crystals.
abstract: We report studies on the temperature dependent alignment behavior of a homologous series of trans, trans- 4, 4'-dialkyl-(1α,1' α-bicyclohexyl)-4β-carbonitrile (CCNs) on a perfluoropolymer coated cells. Among six compounds in the series, one (CCN-35) has only nematic phase and the remaining five have either smectic-A or smectic-B in addition to the nematic phase. We simultaneously performed temperature dependent dielectric measurements and optical polarising microscope observation. It is found that except for CCN-35 and CCN-73, the remaining four compounds exhibit discontinuous anchoring transition from planar to homeotropic and vice versa with increasing thermal hysteresis. We developed a simple theory taking into account the effect of smectic short-range order at the substrates to explain the experimental observations.
authors.affiliation: School of Physics, University of Hyderabad, Hyderabad-500046, India.
authors.forename: D Venkata
authors.initials: DV
authors.lastname: Sai
authors.affiliation: School of Physics, University of Hyderabad, Hyderabad-500046, India.
authors.forename: T Arun
authors.initials: TA
authors.lastname: Kumar
authors.affiliation: Darmstadt University of Technology, Eduard- Zintl-Institute for Inorganic and Physical Chemistry, Petersenstr. 20, Darmstadt 64287, Germany.
authors.forename: W
authors.initials: W
authors.lastname: Haase
authors.affiliation: Raman Research Institute, C. V. Raman Avenue, Bangalore-500080, India.
authors.forename: Arun
authors.initials: A
authors.lastname: Roy
authors.affiliation: School of Physics, University of Hyderabad, Hyderabad-500046, India.
authors.forename: Surajit
authors.initials: S
authors.lastname: Dhara