Liquid crystalline 3-, 4- and 6-armed star molecules based on nitromethane-trispropanol or pentaerythritol without mesogen spacers |
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Authors: | L M Wilson |
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Institution: |
a Melville Laboratory for Polymer Synthesis, University of Cambridge, Cambridge, England |
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Abstract: | Some molecules of unusual shape and apparently non-linear geometry, with mesogens tied directly to a central unit (for example, tetrahedral pentaerythritol), have been investigated for liquid crystalline behaviour. It was found that these three-, four- and six-armed 'star' molecules generated liquid crystalline mesophases, which were characterized by DSC, optical microscopy and X-ray diffraction. The temperature ranges of the fluid mesophases for the thermotropic compounds were above 158°C for the three-armed molecules and above 219°C for the four-and six-armed 'stars'. All the liquid crystalline compounds exhibited a smectic phase, which appears to be smectic A, with the molecules in their fully extended conformations within the layers. Some of the compounds also had a smectic phase of higher order or a nematic phase. |
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