Oscillating Poiseuille flow in photo‐aligned liquid crystal cells
| Autor: | Liu Zhijian, Sergey V. Pasechnik, Valentin A. Tsvetkov, Ildar Nasibullayev, Vladimir G. Chigrinov, Dina V. Shmeliova |
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| Rok vydání: | 2006 |
| Předmět: |
Materials science
business.industry Homeotropic alignment General Chemistry Condensed Matter Physics Hagen–Poiseuille equation Molecular physics Condensed Matter::Soft Condensed Matter Viscosity Boundary layer Optics Planar Liquid crystal Ultraviolet light General Materials Science business Pressure gradient |
| Zdroj: | Liquid Crystals. 33:1153-1165 |
| ISSN: | 1366-5855 0267-8292 |
| DOI: | 10.1080/02678290600965457 |
| Popis: | We present an experimental study of thin liquid crystal (LC) layers under the action of a harmonically varied pressure gradient. Optical measurements were performed to register the linear oscillations of a nematic director related to homeotropic and homeoplanar (hybrid) initial states. In the latter case one of the inner surfaces of the rectangular channels was treated by ultraviolet light to provide a relatively weak planar anchoring. The optical response of hybrid and homeotropic LC cells under an oscillating pressure gradient was investigated in relation to on the amplitude and frequency of the pressure gradient. A hydrodynamic model is developed taking into account the LC polar anchoring strength and the surface viscosity responsible for a fast LC surface dynamics. Our estimates show that the thickness of the boundary layer corresponding to the surface viscosity does not exceed 10−6 m, and further experiments are needed with thinner LC cells and higher frequency oscillations to achieve a more precise ... |
| Databáze: | OpenAIRE |
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