scholarly journals Doping liquid crystals with nanoparticles. A computer simulation of the effects of nanoparticle shape

2016 ◽  
Vol 18 (4) ◽  
pp. 2428-2441 ◽  
Author(s):  
Silvia Orlandi ◽  
Erika Benini ◽  
Isabella Miglioli ◽  
Dean R. Evans ◽  
Victor Reshetnyak ◽  
...  
Keyword(s):  
Computer Simulation ◽  
Monte Carlo ◽  
Liquid Crystal ◽  
Liquid Crystals ◽  
Monte Carlo Simulations ◽  
Orientational Order ◽  
Nanoparticle Shape ◽  
Nanoparticle Dispersions ◽  
Molecular Scale ◽  
Clearing Temperature

Molecular-scale Monte Carlo simulations of liquid crystal-nanoparticle dispersions show the effect on the orientational order and on the clearing temperature of shape and concentration of the dopant nanoparticles.

Line broadening in the electron resonance spectra of spin probes dissolved in anisotropic media: the effect of nuclear spin quantization

1977 ◽  
Vol 353 (1672) ◽  
pp. 87-102 ◽  
Keyword(s):  
Liquid Crystal ◽  
Liquid Crystals ◽  
Nuclear Spin ◽  
Dynamic Properties ◽  
Orientational Order ◽  
Anisotropic Media ◽  
Approximate Theory ◽  
Spin Probes ◽  
Line Broadening ◽  
Electron Resonance

The line broadening in the electron resonance spectra of monoradicals dissolved in anisotropic media, such as liquid crystals, provides a valuable probe of both the orientational order and the molecular dynamics. However, the fast-motion relaxation theory employed to extract this information from the linewidths assumes that the nuclear spin is quantized along the direction of the magnetic field. This approximation is only correct when the symmetry axis of a uniaxial liquid crystal is either parallel or perpendicular to the field. We have therefore removed this assumption and have developed a general theory of line broadening valid for all orientations of the liquid crystal. The theory is then used to evaluate the angular dependence of the linewidths and this is compared with the dependence predicted by the approximate theory, for two classes of nitroxide spin probes. These comparisons reveal that for steroidal spin probes the error, introduced by assuming the nuclear spin to be quantized along the field, is confined to the dynamic properties derived from the linewidths. In contrast, significant errors appear in both the dynamic and static properties obtained from an analysis of the linewidth variations for fatty acid spin probes based on the approximate theory. It would seem that the exact theory must be employed to obtain precise information from linewidth investigations of liquid crystals, except when the orientational order is extremely small.

The structure of polymer brushes near the transition from dilute to dense systems. A computer simulation study

Soft Matter ◽  
2021 ◽  
Author(s):  
Piotr Polanowski ◽  
Andrzej Sikorski
Keyword(s):  
Computer Simulation ◽  
Monte Carlo ◽  
Monte Carlo Simulations ◽  
Simulation Study ◽  
Polymer Brushes ◽  
Polymer Brush ◽  
Coarse Grained ◽  
Computer Simulation Study ◽  
Coarse Grained Model ◽  
Cooperative Motion

Monodisperse polymer brushes were studied by means of Monte Carlo simulations. A coarse-grained model of a polymer brush was designed in order and the Cooperative Motion Algorithm was employed to...

The Relation Between Defects and Relaxation in Viscous Liquids

1985 ◽  
Vol 61 ◽  
Author(s):  
S. Brawer
Keyword(s):  
Computer Simulation ◽  
Monte Carlo ◽  
Ising Model ◽  
Monte Carlo Simulations ◽  
Relaxation Behavior ◽  
Atomic Diffusion ◽  
Kinetic Ising Model ◽  
Viscous Liquids ◽  
First Approximation

ABSTRACTIt is shown that defects can be identified in liquids, that they are related to atomic diffusion, and a model is described whereby defects give rise to the observed relaxation behavior of viscous liquids. A review is presented of defects in silicate and fluoroberyllate liquids, as studied by computer simulation. It is found that defects have the form of overcoordinated or undercoordinated atoms, and that atomic diffusion occurs only at the site of defects. The manner in which an Ising model can represent the detect structure of viscous liquids to a first approximation is presented. The results of Monte Carlo simulations of a 2-dimensional kinetic Ising model are described. The behavior of this model is qualitatively the same as that of viscous liquids.

scholarly journals Liquid crystals of carbon nanotubes and graphene

2013 ◽  
Vol 371 (1988) ◽  
pp. 20120499 ◽  
Author(s):  
Cécile Zakri ◽  
Christophe Blanc ◽  
Eric Grelet ◽  
Camilo Zamora-Ledezma ◽  
Nicolas Puech ◽  
...  
Keyword(s):  
Liquid Crystal ◽  
Liquid Crystals ◽  
Order Parameter ◽  
Orientational Order ◽  
Point Of View ◽  
General Point ◽  
Conductivity Anisotropy ◽  
Conductive Films ◽  
Experimental Approaches ◽  
New Methodologies

Liquid crystal ordering is an opportunity to develop novel materials and applications with spontaneously aligned nanotubes or graphene particles. Nevertheless, achieving high orientational order parameter and large monodomains remains a challenge. In addition, our restricted knowledge of the structure of the currently available materials is a limitation for fundamental studies and future applications. This paper presents recent methodologies that have been developed to achieve large monodomains of nematic liquid crystals. These allow quantification and increase of their order parameters. Nematic ordering provides an efficient way to prepare conductive films that exhibit anisotropic properties. In particular, it is shown how the electrical conductivity anisotropy increases with the order parameter of the nematic liquid crystal. The order parameter can be tuned by controlling the length and entanglement of the nanotubes. In the second part of the paper, recent results on graphene liquid crystals are reported. The possibility to obtain water-based liquid crystals stabilized by surfactant molecules is demonstrated. Structural and thermodynamic characterizations provide indirect but statistical information on the dimensions of the graphene flakes. From a general point of view, this work presents experimental approaches to optimize the use of nanocarbons as liquid crystals and provides new methodologies for the still challenging characterization of such materials.

scholarly journals Singlet Excitation Transfer in Columnar Liquid Crystals Studied by Monte Carlo Simulations

1996 ◽  
Vol 100 (26) ◽  
pp. 10999-11004 ◽  
Author(s):  
Hervé Sigal ◽  
Dimitra Markovitsi ◽  
Lazaros K. Gallos ◽  
Panos Argyrakis
Keyword(s):  
Monte Carlo ◽  
Liquid Crystals ◽  
Monte Carlo Simulations ◽  
Excitation Transfer
Sign in / Sign up

Export Citation Format

Share Document