Spatial Dimensionality of a Liquid Crystal Lattice

1992 ◽  
Vol 215 (1) ◽  
pp. 331-338
Author(s):  
E. E. Gorodetskii ◽  
V. E. Podneks
Keyword(s):  
Liquid Crystal ◽  
Crystal Lattice ◽  
Spatial Dimensionality

Liquid Crystal Lattice Models I. Bulk Systems

2000 ◽  
pp. 99-119 ◽  
Author(s):  
Paolo Pasini ◽  
Cesare Chiccoli ◽  
Claudio Zannoni
Keyword(s):  
Liquid Crystal ◽  
Crystal Lattice ◽  
Lattice Models

Giant Supramolecular Liquid Crystal Lattice

Science ◽  
2003 ◽  
Vol 299 (5610) ◽  
pp. 1208-1211 ◽  
Author(s):  
G. Ungar
Keyword(s):  
Liquid Crystal ◽  
Crystal Lattice

Liquid Crystal Lattice Models on Quadrics Supercomputers

1997 ◽  
Vol 08 (03) ◽  
pp. 547-554 ◽  
Author(s):  
Sigismondo Boschi ◽  
Marco P. Brunelli ◽  
Claudio Zannoni ◽  
Cesare Chiccoli ◽  
Paolo Pasini
Keyword(s):  
Phase Transition ◽  
Monte Carlo ◽  
Liquid Crystal ◽  
Crystal Lattice ◽  
Applied Field ◽  
Lattice Models ◽  
Massively Parallel ◽  
Isotropic Phase ◽  
Monte Carlo Code

The implementation of a Monte Carlo code for simulations of liquid crystal lattice models on the Quadrics massively parallel SIMD supercomputer is described. The use of a Quadrics with 512 processors is proving essential in studying the nematic–isotropic phase transition to an unprecedented level of accuracy using more than 106 particles. Here some tests on the Lebwohl–Lasher model with and without an applied field are presented.

THREE-DIMENSIONAL VISUALIZATION OF MOLECULAR ORGANIZATION AND PHASE TRANSITIONS IN LIQUID CRYSTAL LATTICE MODELS

1992 ◽  
Vol 03 (06) ◽  
pp. 1209-1220 ◽  
Author(s):  
CESARE CHICCOLI ◽  
PAOLO PASINI ◽  
FRANCO SEMERIA ◽  
CLAUDIO ZANNONI
Keyword(s):  
Monte Carlo ◽  
Liquid Crystal ◽  
Crystal Lattice ◽  
Personal Computer ◽  
Three Dimensional ◽  
Lattice Models ◽  
Point Of View ◽  
Molecular Organization ◽  
Computer Visualization ◽  
Physical Information

An example of three-dimensional animation of Monte Carlo simulation results of liquid crystal lattice models is presented. Molecular configurations are obtained from Monte Carlo simulations on a VAX cluster and downloaded to a 486 personal computer. Visualization of molecular organizations and of their change at a phase transition is obtained by suitable colour coding of orientations and of other relevant physical information on the personal computer, and recorded on a VHS system using a genlock card. The animation sequences generated have a twofold interest: they are useful for educational purposes and, from a scientific point of view, they provide a tool for exploring a large amount of data and investigating the phenomena under study in a non-numerical way.

Freeze-fracture TEM of the helical smectic A* phase

1992 ◽  
Vol 50 (1) ◽  
pp. 278-279
Author(s):  
K.J. Ihn ◽  
R. Pindak ◽  
J. A. N. Zasadzinski
Keyword(s):  
Liquid Crystal ◽  
Grain Boundary ◽  
Grain Boundaries ◽  
Freeze Fracture ◽  
Smectic Phase ◽  
Layer Spacing ◽  
Screw Dislocations ◽  
Smectic A ◽  
Smectic Phases ◽  
Discrete Amount

A new liquid crystal (called the smectic-A* phase) that combines cholesteric twist and smectic layering was a surprise as smectic phases preclude twist distortions. However, the twist grain boundary (TGB) model of Renn and Lubensky predicted a defect-mediated smectic phase that incorporates cholesteric twist by a lattice of screw dislocations. The TGB model for the liquid crystal analog of the Abrikosov phase of superconductors consists of regularly spaced grain boundaries of screw dislocations, parallel to each other within the grain boundary, but rotated by a fixed angle with respect to adjacent grain boundaries. The dislocations divide the layers into blocks which rotate by a discrete amount, Δθ, given by the ratio of the layer spacing, d, to the distance between grain boundaries, lb; Δθ ≈ d/lb (Fig. 1).

Attractive mode force microscopy of chiral liquid crystal surfaces

1992 ◽  
Vol 50 (1) ◽  
pp. 268-269
Author(s):  
B.D. Terris ◽  
R. J. Twieg ◽  
C. Nguyen ◽  
G. Sigaud ◽  
H. T. Nguyen
Keyword(s):  
Liquid Crystal ◽  
Crystal Surfaces ◽  
Free Surfaces ◽  
Control Range ◽  
Force Microscopy ◽  
Liquid Crystal Films ◽  
Chiral Liquid Crystal ◽  
Crystal Films ◽  
Electrostatic Charging ◽  
And Shifts

We have used a force microscope in the attractive, or noncontact, mode to image a variety of surfaces. In this mode, the microscope tip is oscillated near its resonant frequency and shifts in this frequency due to changes in the surface-tip force gradient are detected. We have used this technique in a variety of applications to polymers, including electrostatic charging, phase separation of ionomer surfaces, and crazing of glassy films.Most recently, we have applied the force microscope to imaging the free surfaces of chiral liquid crystal films. The compounds used (Table 1) have been chosen for their polymorphic variety of fluid mesophases, all of which exist within the temperature control range of our force microscope.

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