Cryo-TEM studies of two smectic phases of an asymmetric bent-core material |
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Authors: | C. Zhang B.K. Sadashiva O.D. Lavrentovich |
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Affiliation: | 1. Chemical Physics Interdisciplinary Program and Liquid Crystal Institute, Kent State University, Kent, OH, 44242, USA;2. Raman Research Institute, C.V. Raman Avenue, Bangalore, 560080, India |
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Abstract: | Cryo-TEM studies on two smectic phases of an asymmetric bent-core liquid crystal material are presented and compared to prior X-ray results obtained in bulk samples. While the bulk samples have layer-modulated structures, those modulations are not observable in the 100-nm-thick TEM samples, indicating surface-induced suppression of the layer modulations. The observed layer spacing is in agreement with the X-ray results in the lower temperature smectic phase, but distinctly larger in the higher temperature phase. This indicates surface-induced suppression of the director tilt. Cryo-TEM textures resolve the profiles of individual smectic layers at the scales down to few nanometres and reveal the presence of edge and screw dislocations, twist grain boundaries, small-angle and large-angle tilt grain boundaries. |
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Keywords: | smectic electron microscopy defects nanostructure |
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