Self-Alignment of Dye Molecules in Micelles and Lamellae for Three-Dimensional Imaging of Lyotropic Liquid Crystals

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• 作者：Qingkun Liu ; Corinne Beier ; Julian Evans ; Taewoo Lee ; Sailing He ; Ivan I. Smalyukh
• 刊名：Langmuir
• 出版年：2011
• 出版时间：June 21, 2011
• 年：2011
• 卷：27
• 期：12
• 页码：7446-7452
• 全文大小：1037K
• 年卷期：v.27,no.12(June 21, 2011)
• ISSN：1520-5827

文摘

We report alignment of anisotropic amphiphilic dye molecules within oblate and prolate anisotropic micelles and lamellae, the basic building blocks of surfactant-based lyotropic liquid crystals. Absorption and fluorescence transition dipole moments of these dye molecules orient either parallel or orthogonal to the liquid crystal director. This alignment enables three-dimensional visualization of director structures and defects in different lyotropic mesophases by means of fluorescence confocal polarizing microscopy and two-photon excitation fluorescence polarizing microscopy. The studied structures include nematic tactoids, Schlieren texture with disclinations in the calamitic nematic phase, oily streaks in the lamellar phase, developable domains in the columnar hexagonal phase, and various types of line defects in the discotic cholesteric phase. Orientational three-dimensional imaging of structures in the lyotropic cholesterics reveals large Burgers vector dislocations in cholesteric layering with singular disclinations in the dislocation cores that are not common for their thermotropic counterparts.