Thermal phase diagrams of columnar liquid crystals

Thermal phase diagram of a model Hamiltonian for columnar phases of liquid crystals.

We present the phase diagram and critical properties of a coupled XY Ising model on a triangular lattice using the mean-field approximation, the Migdal-Kadanoff scheme of renormalization group and Monte-Carlo simulations. The topology of the phase diagram is similar for the three techniques, with the appearance of a phase with XY order and Ising disorder. The results suggest a line of transitio...

Dielectric Investigations on Ferroelectric Columnar Liquid Crystals

Pseudolayered structure of the columnar B1 phase of bent-core liquid crystals.

Three bent-core liquid-crystal compounds presenting the unusual columnar B1 to tilted polar smectic (Sm-CP or B2) phase transition are studied through small-angle x-ray diffraction on aligned samples. The well-established character of the smectic phase helps to characterize the structural changes during the transition. A mechanism for this transition is proposed, which accounts for the low enth...

Separated local field spectroscopy of columnar and nematic liquid crystals.

We are in this work comparing the efficiencies of various 1H-13C separated local field (SLF) experiments when applied to columnar and nematic liquid crystals. In particular, the performances of the conventional SLF, proton-detected local field (PDLF), and polarization inversion spin exchange at the magic angle (PISEMA) methods in terms of spectral resolution, robustness, and ability to measure ...

Heterogeneous dynamics in columnar liquid crystals of parallel hard rods.

In the wake of previous studies on the rattling-and-jumping diffusion in smectic liquid crystal phases of colloidal rods, we analyze here for the first time the heterogeneous dynamics in columnar phases. More specifically, we perform computer simulations to investigate the relaxation dynamics of a binary mixture of perfectly aligned hard spherocylinders. We detect that the columnar arrangement ...