Relaxation processes and structure of electric double layers at the liquid crystal-solid substrate interface

1996 ◽  
Author(s):  
Alexandr V. Koval'chuk
Keyword(s):  
Liquid Crystal ◽  
Solid Substrate ◽  
Double Layers ◽  
Relaxation Processes ◽  
Electric Double Layers ◽  
Substrate Interface

Weak anchoring resolved substrate interface and bulk mode processes in surface stabilized ferroelectric liquid crystal

2021 ◽  
Vol 325 ◽  
pp. 114705
Author(s):  
Sidra Khan ◽  
Jai Prakash ◽  
Shikha Chauhan ◽  
Amit Choudhary ◽  
Ashok M. Biradar
Keyword(s):  
Liquid Crystal ◽  
Ferroelectric Liquid Crystal ◽  
Substrate Interface ◽  
Bulk Mode

Molecular dynamics simulation of adsorption in electric double layers

1995 ◽  
Vol 335 ◽  
pp. 422-431 ◽  
Author(s):  
Michael R. Philpott ◽  
James N. Glosli ◽  
Sheng-Bai Zhu
Keyword(s):  
Molecular Dynamics ◽  
Molecular Dynamics Simulation ◽  
Dynamics Simulation ◽  
Double Layers ◽  
Electric Double Layers

Phase equilibria in solutions of rod-like particles

1956 ◽  
Vol 234 (1196) ◽  
pp. 73-89 ◽  
Keyword(s):  
Free Energy ◽  
Phase Separation ◽  
Partition Function ◽  
Colloidal Particles ◽  
Double Layers ◽  
Positive Energy ◽  
Isotropic Phase ◽  
Electric Double Layers ◽  
Rigid Rod ◽  
Anisotropic Phase

A partition function for a system of rigid rod-like particles with partial orientation about an axis is derived through the use of a modified lattice model. In the limit of perfect orientation the partition function reduces to the ideal mixing law ; for complete disorientation it corresponds to the polymer mixing law for rigid chains. A general expression is given for the free energy of mixing as a function of the mole numbers, the axis ratio of the solute particles, and a disorientation parameter. This function passes through a minimum followed by a maximum with increase in the disorientation parameter, provided the latter exceeds a critical value which is 2e for the pure solute and which increases with dilution. Assigning this parameter the value which minimizes the free energy, the chemical potentials display discontinuities a t the concentration a t which the minimum first appears. Separation into an isotropic phase and a some what more concentrated anisotropic phase arises because of the discontinuity, in confirmation of the theories of Onsager and Isihara, which treat only the second virial coefficient. Phase separation thus arises as a consequence of particle asymmetry, unassisted by an energy term . Whereas for a large-particle asymmetry both phases in equilibrium are predicted to be fairly dilute when mixing is athermal, a comparatively small positive energy of interaction causes the concentration in the anisotropic phase to increase sharply, while the concentration in the isotropic phase becomes vanishingly small. The theory offers a statistical mechanical basis for interpreting precipitation of rod-like colloidal particles with the formation of fibrillar structures such as are prominent in the fibrous proteins. The asymmetry of tobacco mosaic virus particles (with or without inclusion of their electric double layers) is insufficient alone to explain the well-known phase separation which occurs from their dilute solutions at very low ionic strengths. Higher-order interaction between electric double layers appears to be a major factor in bringing about dilute phase separation for these and other asymmetric colloidal particles bearing large charges, as was pointed out previously by Oster.

EFFECT OF CELL THICKNESS ON THE DIELECTRIC RELAXATION PROCESSES IN FERROELECTRIC LIQUID CRYSTALS

2008 ◽  
Vol 22 (14) ◽  
pp. 2263-2273 ◽  
Author(s):  
RAJBIR SINGH ◽  
K. K. RAINA
Keyword(s):  
Liquid Crystal ◽  
Dielectric Relaxation ◽  
Dielectric Strength ◽  
Relaxation Processes ◽  
Goldstone Mode ◽  
Ferroelectric Liquid Crystal ◽  
Dielectric Relaxation Spectroscopy ◽  
Dielectric Parameters ◽  
Liquid Crystal Material ◽  
Cell Thickness

Dielectric relaxation spectroscopy in the frequency range 50 Hz to 1 MHz has been carried out in a room temperature ferroelectric liquid crystal mixture in the SmC*, SmA and N* phases in cells of different thickness. The relaxation frequency fr, distribution parameter α and dielectric strength δ∊ have been evaluated. Goldstone mode, domain mode and soft mode have been observed. It is found that the cell thickness has a significant effect on the dielectric parameters of the ferroelectric liquid crystal material. The results have been discussed.

CHARGE CHARACTERISTICS ON THE CLAY SURFACE WITH INTERACTING ELECTRIC DOUBLE LAYERS

Soil Science ◽  
2001 ◽  
Vol 166 (4) ◽  
pp. 249-254 ◽  
Author(s):  
Xin Jiang ◽  
Jianmin Zhou ◽  
Maoxu Zhu ◽  
Wenxiang He ◽  
Guifen Yu
Keyword(s):  
Double Layers ◽  
Electric Double Layers ◽  
Clay Surface

Electromigration of Charged Polystyrene Beads Through Silicon Nanopores Filled With Low Ionic Strength Solutions

2009 ◽  
Author(s):  
Punarvasu Joshi ◽  
Trupthi Mathew ◽  
Leo Petrossian ◽  
Shalini Prasad ◽  
Michael Goryll ◽  
...  
Keyword(s):  
Ionic Strength ◽  
Double Layers ◽  
Electric Double Layers ◽  
Ionic Solution ◽  
Polystyrene Beads ◽  
Detailed Statistical Analysis ◽  
Charge Interaction ◽  
Pass Through ◽  
Low Ionic Strength ◽  
Bulk Behavior

In this work we present preliminary results demonstrating the influence of electrical double layer overlap on the electromigration of polystyrene beads (PSB) through an array of 25 cylindrical nanopores. Each of the cylindrical nanopores of the array used in this study is 360nm long with a diameter of 90nm. We observe frequent Coulter events for solutions of higher ionic strength and absence of Coulter events at low ionic strength solution. At higher ionic strengths, the electric double layers in the nanopore are thin and ion transport through the nanopore follows the bulk behavior of the ionic solution. For solutions of lower ionic strength, the electric double layers are comparable to the nanopore dimensions and start to overlap, suggesting surface charge interaction with the polystyrene beads that pass through the nanopore. The work continues towards detailed statistical analysis of the characteristic events observed for different concentrations.

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