title: Pretransitional orientational ordering of a calamitic liquid crystal by helical nanofilaments of a bent-core mesogen.
abstract: Mixtures of 8CB (a calamitic mesogen) and NOBOW (P-9-O-PIMB, a bent-core mesogen) have been investigated using differential scanning calorimetry, nuclear magnetic resonance spectroscopy, and freeze fracture transmission electron microscopy. On cooling the isotropic mixture, the NOBOW component phase separates, forming a dilute, random network of helical nanofilaments in the B4 phase with isotropic 8CB material filling the interstitial volume. At lower temperature, but still far above the bulk isotropic-nematic transition of pure 8CB, a significant fraction of the 8CB becomes prealigned on the filament surfaces. We propose that this pretransitional ordering is induced by short-range interactions of the polar 8CB molecules with the NOBOW filaments, leading to the formation of an adsorbed film of orientationally frozen 8CB around each filament.
authors.affiliation: Department of Physics and Liquid Crystal Materials Research Center, University of Colorado, Boulder, Colorado 80309-0390, USA.
authors.forename: Dong
authors.initials: D
authors.lastname: Chen
authors.forename: Chenhui
authors.initials: C
authors.lastname: Zhu
authors.forename: Richard K
authors.initials: RK
authors.lastname: Shoemaker
authors.forename: Eva
authors.initials: E
authors.lastname: Korblova
authors.forename: David M
authors.initials: DM
authors.lastname: Walba
authors.forename: Matthew A
authors.initials: MA
authors.lastname: Glaser
authors.forename: Joseph E
authors.initials: JE
authors.lastname: Maclennan
authors.forename: Noel A
authors.initials: NA
authors.lastname: Clark