Dynamics of Order Reconstruction in a Nanoconfined Nematic Liquid Crystal with a Topological Defect
At the wall in a hybrid nematic cell with strong anchoring, the nematic director is parallel to one wall and perpendicular to the other. Within the Landau-de Gennes theory, we have investigated the dynamics of s = ±1/2 wedge disclinations in such a cell, using the two-dimensional finite-difference i...
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doaj-e67bc0ed1fb74f8086cbb1de818ff65d2020-11-24T22:01:01ZengMDPI AGInternational Journal of Molecular Sciences1422-00672013-12-011412241352415310.3390/ijms141224135ijms141224135Dynamics of Order Reconstruction in a Nanoconfined Nematic Liquid Crystal with a Topological DefectXuan Zhou0Zhidong Zhang1Department of physics, Hebei University of Technology, Tianjin 300401, ChinaDepartment of physics, Hebei University of Technology, Tianjin 300401, ChinaAt the wall in a hybrid nematic cell with strong anchoring, the nematic director is parallel to one wall and perpendicular to the other. Within the Landau-de Gennes theory, we have investigated the dynamics of s = ±1/2 wedge disclinations in such a cell, using the two-dimensional finite-difference iterative method. Our results show that with the cell gap decreasing, the core of the defect explodes, and the biaxiality propagates inside the cell. At a critical value of dc* ≈ 9ξ (where ξ is the characteristic length for order-parameter changes), the exchange solution is stable, while the defect core solution becomes metastable. Comparing to the case with no initial disclination, the value at which the exchange solution becomes stable increases relatively. At a critical separation of dc ≈ 6ξ, the system undergoes a structural transition, and the defect core merges into a biaxial layer with large biaxiality. For weak anchoring boundary conditions, a similar structural transition takes place at a relative lower critical value. Because of the weakened frustration, the asymmetric boundary conditions repel the defect to the weak anchoring boundary and have a relatively lower critical value of da, where the shape of the defect deforms. Further, the response time between two very close cell gaps is about tens of microseconds, and the response becomes slower as the defect explodes.http://www.mdpi.com/1422-0067/14/12/24135biaxial transitiontopological defecteigenvalue exchangeresponse time |
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DOAJ |
language |
English |
format |
Article |
sources |
DOAJ |
author |
Xuan Zhou Zhidong Zhang |
spellingShingle |
Xuan Zhou Zhidong Zhang Dynamics of Order Reconstruction in a Nanoconfined Nematic Liquid Crystal with a Topological Defect International Journal of Molecular Sciences biaxial transition topological defect eigenvalue exchange response time |
author_facet |
Xuan Zhou Zhidong Zhang |
author_sort |
Xuan Zhou |
title |
Dynamics of Order Reconstruction in a Nanoconfined Nematic Liquid Crystal with a Topological Defect |
title_short |
Dynamics of Order Reconstruction in a Nanoconfined Nematic Liquid Crystal with a Topological Defect |
title_full |
Dynamics of Order Reconstruction in a Nanoconfined Nematic Liquid Crystal with a Topological Defect |
title_fullStr |
Dynamics of Order Reconstruction in a Nanoconfined Nematic Liquid Crystal with a Topological Defect |
title_full_unstemmed |
Dynamics of Order Reconstruction in a Nanoconfined Nematic Liquid Crystal with a Topological Defect |
title_sort |
dynamics of order reconstruction in a nanoconfined nematic liquid crystal with a topological defect |
publisher |
MDPI AG |
series |
International Journal of Molecular Sciences |
issn |
1422-0067 |
publishDate |
2013-12-01 |
description |
At the wall in a hybrid nematic cell with strong anchoring, the nematic director is parallel to one wall and perpendicular to the other. Within the Landau-de Gennes theory, we have investigated the dynamics of s = ±1/2 wedge disclinations in such a cell, using the two-dimensional finite-difference iterative method. Our results show that with the cell gap decreasing, the core of the defect explodes, and the biaxiality propagates inside the cell. At a critical value of dc* ≈ 9ξ (where ξ is the characteristic length for order-parameter changes), the exchange solution is stable, while the defect core solution becomes metastable. Comparing to the case with no initial disclination, the value at which the exchange solution becomes stable increases relatively. At a critical separation of dc ≈ 6ξ, the system undergoes a structural transition, and the defect core merges into a biaxial layer with large biaxiality. For weak anchoring boundary conditions, a similar structural transition takes place at a relative lower critical value. Because of the weakened frustration, the asymmetric boundary conditions repel the defect to the weak anchoring boundary and have a relatively lower critical value of da, where the shape of the defect deforms. Further, the response time between two very close cell gaps is about tens of microseconds, and the response becomes slower as the defect explodes. |
topic |
biaxial transition topological defect eigenvalue exchange response time |
url |
http://www.mdpi.com/1422-0067/14/12/24135 |
work_keys_str_mv |
AT xuanzhou dynamicsoforderreconstructioninananoconfinednematicliquidcrystalwithatopologicaldefect AT zhidongzhang dynamicsoforderreconstructioninananoconfinednematicliquidcrystalwithatopologicaldefect |
_version_ |
1725842310819741696 |