Kinetics and Statistics of Topological Defects in the Phase Ordering of Liquid Crystals
| Project/Area Number |
07640509
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
物性一般(含基礎論)
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| Research Institution | Yamanashi University |
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Principal Investigator |
TOYOKI Hiroyasu Yamanashi University Faculty of Liberal Arts and Education Associate Professor, 教育学部, 助教授 (40172209)
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| Project Period (FY) |
1995 – 1996
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| Project Status |
Completed (Fiscal Year 1996)
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| Budget Amount *help |
¥2,300,000 (Direct Cost: ¥2,300,000)
Fiscal Year 1996: ¥500,000 (Direct Cost: ¥500,000)
Fiscal Year 1995: ¥1,800,000 (Direct Cost: ¥1,800,000)
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| Keywords | nematic liquid crystal / hybrid boundary condition / boojum / cell dynamical system / 秩序形成過程 / 液晶薄膜 / 秩序化過程 / 位相欠陥 / 動的スケール則 / ディスクリネーション / 表面欠陥 |
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| Research Abstract |
Equilibrium patterns and those formation process in thin nematic films under hybrid boundary conditions are numerically investigated. The top boundary is homeotropic one where the director is perpendicular to the film and the bittom boundary is homogeneous one where the director is parallel to the film. The surface terms of energy represented by surface integrals in the Frank energy have an important role for forming patterns, thourh those have been neglected in bulk problems. Our present model is an improved cell-dynamical-system model, which does not only includes the surface terms but alsobe able to represent the anisotropy of bulk elastic constants. A main idea is that we do not discretize the Frank energy but does the TDGL equation.
The competition between the surface energy and the bulk energy makes periodically modulated patterns. The present simulation shows that periodic pattern is stable above the onset value of the surface constant K_<24>=0.35 and the period is proportional to (K_<24>-K_<13>/2)^<-1> for large K_<24>.
The anisotropy due to the lattice affects the direction of the striped pattern. To avoid this unphysical effect, the second nearest interaction must be taken into account.
The effect of anisotropic on-site fields at the homogeneous boundary is examined. The unidirectional field makes is found to make string-like Schlieren patterns between a boojum and an antiboojum similar to experimental patterns in films of thickness about 10mum.
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Report
(3 results)
Research Products
(3 results)
