Arrays of Aligned Supramolecular Wires by Macroscopic Orientation of Columnar Discotic Mesophases

ACS Nano ◽  
2012 ◽  
Vol 6 (11) ◽  
pp. 9359-9365 ◽  
Author(s):  
Hatice Duran ◽  
Brigitte Hartmann-Azanza ◽  
Martin Steinhart ◽  
Dominik Gehrig ◽  
Frédéric Laquai ◽  
...  
Keyword(s):  
Macroscopic Orientation

APPLICATION OF FINITE ELEMENT METHOD TO SOLVE 2D PROBLEMS RELATED TO NEMATIC SURFACE PROPERTIES

1999 ◽  
Vol 10 (02n03) ◽  
pp. 485-500
Author(s):  
R. BARBERI ◽  
M. IOVANE ◽  
C. FERRERO ◽  
V. MOCELLA
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Boundary Conditions ◽  
Surface Properties ◽  
Periodic Boundary Conditions ◽  
The Third ◽  
Numerical Studies ◽  
Nematic Director ◽  
Macroscopic Orientation ◽  
Element Method

This paper is devoted to numerical studies of two-dimensional problems concerning surface properties of nematic liquid crystals. We use a finite element method, based essentially on the classic variational approach, to find an approximate solution minimizing the Gibbs free energy of the nematic material under given boundary conditions. Three examples illustrate the performance and versatility of this analysis. Two cases are related to the macroscopic orientation induced by periodic boundary conditions: the first is a saw-toothed substrate in the micrometric range and the second is a microtextured surface. We analyze the bulk planar–homeotropic transition conditions for both of them. In the third case, we study the coupling between the spatial variation of the nematic director and that of the order parameter in the presence of surface-induced distortion.

Detection of macroscopic orientation effects in Illinois No. 6 coal by solid-state NMR techniques

1991 ◽  
Vol 5 (5) ◽  
pp. 619-624 ◽  
Author(s):  
James E. Roberts ◽  
Kellie M. Coleman ◽  
Michael H. Alaimo ◽  
John W. Larsen
Keyword(s):  
Solid State ◽  
Solid State Nmr ◽  
Orientation Effects ◽  
Nmr Techniques ◽  
Macroscopic Orientation

First evidences of macroscopic orientation of benzene in C60.4C6H6 solvate at 293 K

2008 ◽  
Vol 147 (1-2) ◽  
pp. 49-52
Author(s):  
Francis Masin ◽  
Anne Sophie Grell ◽  
Michel Gelbcke ◽  
Jérôme Giraudet
Keyword(s):  
Macroscopic Orientation

scholarly journals Macroscopic Orientation of Natural and Model Membranes for Structural Studies

1997 ◽  
Vol 254 (1) ◽  
pp. 132-138 ◽  
Author(s):  
Gerhard Gröbner ◽  
Andrew Taylor ◽  
Philip T.F. Williamson ◽  
Gregory Choi ◽  
Clemens Glaubitz ◽  
...  
Keyword(s):  
Model Membranes ◽  
Structural Studies ◽  
Macroscopic Orientation

Macroscopic Orientation Patterns in Smectic-CFilms

1980 ◽  
Vol 45 (14) ◽  
pp. 1193-1196 ◽  
Author(s):  
R. Pindak ◽  
C. Y. Young ◽  
R. B. Meyer ◽  
N. A. Clark
Keyword(s):  
Macroscopic Orientation

Orientation in stretched polymer-dispersed liquid crystals

1998 ◽  
Vol 76 (11) ◽  
pp. 1642-1647 ◽  
Author(s):  
Julien Brazeau ◽  
Yanick Chénard ◽  
Yue Zhao
Keyword(s):  
Liquid Crystal ◽  
Liquid Crystals ◽  
Molecular Orientation ◽  
Liquid Crystalline ◽  
Polymer Dispersed Liquid Crystals ◽  
Polymer Dispersed ◽  
Infrared Dichroism ◽  
Semicrystalline Matrix ◽  
Macroscopic Orientation ◽  
Strain Direction

The orientation behavior of liquid crystal molecules in stretched films of polymer-dispersed liquid crystals (PDLC) was investigated by means of infrared dichroism. The liquid crystal used is 4prime-octyl-4-biphenyl-carbonitrile (8CN); the polymer matrices are semicrystalline poly(epsilon-caprolactone) (PCL) and an amorphous miscible blend of PCL with poly(vinyl chloride) (PVC). 8CN was found to have a limit of solubility below 5 wt.% in PCL. We show that an uniaxial stretching can effectively induce a macroscopic orientation of 8CN, and that this orientation can be preserved in the films after removal of the extensional force at room temperature, where 8CN is in its liquid crystalline phase. The molecular orientation is obtained even by stretching PDLC films with 8CN in the liquid state. These results suggest that an elongated polymer cavity in stretched PDLC imposes LC director fields with respect to the long axes of the droplets, which are aligned parallel to the strain direction. The experiments also reveal that the orientation of 8CN is higher in stretched PDLC with a semicrystalline matrix (PCL) than with an amorphous matrix (the PCL-PVC blend), and that the sizes of the LC droplets also have a slight effect on the induced orientation. This work represents a first step in the exploration of new electrooptical effects of PDLC through the presence of a uniform orientation of the liquid crystal molecules and modifications of the polymer cavity at the electrical field-off state.Key words: polymer-dispersed liquid crystals, molecular orientation, infrared dichroism, electrooptical materials.

Computational Modelling of Mesophase Pitches’ Shear Rheology

2001 ◽  
Vol 709 ◽  
Author(s):  
Dana Grecov ◽  
Alejandro D. Rey
Keyword(s):  
Normal Stress ◽  
Shear Viscosity ◽  
Computational Modelling ◽  
Simple Shear Flow ◽  
Shear Rates ◽  
Extra Stress Tensor ◽  
Normal Stress Differences ◽  
Macroscopic Orientation ◽  
Arbitrary Flow ◽  
Extra Stress

ABSTRACTFlow modelling of mesophase pitches is performed using a previously formulated mesoscopic viscoelastic rheological theory [1] that takes into account flow-induced texture transformations. A complete extra stress tensor equation is developed from first principles for liquid crystal materials under non-homogeneous arbitrary flow. Predictions for a given simple shear flow, under non-homogeneous conditions, for the apparent shear viscosity and first normal stress differences are presented. The rheological functions are explained using macroscopic orientation effects, which predominate at low shear rates. The predicted normal stress differences and apparent shear viscosity are in agreement with experimental measurements.

High Hole Mobility in Triindole-Based Columnar phases: Removing the Bottleneck of Homogeneous Macroscopic Orientation

2013 ◽  
Vol 25 (2) ◽  
pp. 117-121 ◽  
Author(s):  
Angela Benito-Hernández ◽  
Upendra K. Pandey ◽  
Emma Cavero ◽  
Roberto Termine ◽  
Eva M. García-Frutos ◽  
...  
Keyword(s):  
Hole Mobility ◽  
Macroscopic Orientation
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