1,721,009 research outputs found
Elastic anisotropy and anchoring effects on the textures of nematic films with random planar surface alignment
No full textWe present aMonte Carlo study of topological defects in nematic films with random planar boundary conditions. The polarized microscopy images and their evolution are analysed in uniaxial systems for different anchoring strengths and film thicknesses
Lattice spin models of polymer-dispersed liquid crystals
No full textMonte Carlo simulations of lattice spin models are a powerful method for the investigation of confined nematic liquid crystals and allow for a study of the molecular organization and thermodynamics of these systems.
Investigations of models of polymer-dispersed liquid crystals are
reviewed devoting particular attention to the calculation of deuterium NMR spectra from the simulation data
Is internal order in 2D nematic systems destroyed by boundary disorder?
No full textComputer simulations of 2D nematic systems with quenched disorder placed on the oriented boundary have been performed to test the Feldman-Vinokur hypothesis which suggests that the long-range order is destroyed in that case. Our results for various system sizes and different percentages of disorder at the boundary do not necessarily confirm this hypothesis
Monte Carlo Simulations of a Composite Liquid Crystal-Polymer Model System
No full textWe present a Monte Carlo study of a simple model of a liquid crystal-polymer system under the effect of an external applied field. A lattice spin model, based on the Lebwhol-Lasher Hamiltonian and generalized with suitable boundary conditions, has been employed to investigate the molecular organization and to predict the ordering across a sample cell
The effect of varying surface orientation on the molecular organization of nematic films. A Monte Carlo simulation
No full textWe present a Monte Carlo (MC) simulation of a nematic film with boundary conditions that vary from a homogeneous to a homeotropic anchoring at one surface while having a homogeneous anchoring at the other one. The simulations are based on the Lebwohl-Lasher lattice spin model with suitable boundary conditions to mimic the cell. We have investigated temperature effects on the molecular organisation inside the system by calculating the internal energy, the heat capacity and the standard nematic order parameter
Biaxial Nematic Droplets and their Optical Textures. A Lattice Model Computer Simulation Study
No full textMonte Carlo simulations of polarizing microscope textures for confined nematic droplets are presented. We consider uniaxial and biaxial cases with various boundary conditions and different values of the molecular biaxiality. The analysis of these optical textures should be of interest in assigning and characterizing biaxial nematic system, an issue of great current interest
A distributed computing approach to the simulation of liquid crystal lattice models
No full textWe have studied a lattice spin model of nematic liquid crystal-polymer composite films by means of extensive Monte Carlo simulations over a distributed computing network. The Condor processing system installed on the Italian Nuclear Physics Institute computer network was used. The use of several geometries and boundary conditions allowed us to investigate a wide number of different realistic or speculative models. Many of the simulations differ only by a small number of parameters and they can be effectively performed in parallel. The results of the simulations can be analyzed globally when all the computations are completed and then for example, employed to extrapolate Phase Diagrams or other complex physical quantities, They provide an effective example of wide area distributed computing applications which could be also implemented in future GRID approaches
Computer Simulations of Inversion Walls in nematic films
No full textMonte Carlo simulations of lattice spin models are employed to investigate the creation of inversion walls in nematic films with specific boundary conditions. The simulations, based on the well known Lebwohl-Lasher potential, allow to produce simulated polarized
microscopy images which are followed during their evolution and analysed for different film thicknesses
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