| Autor: |
Zhu, Min Hua, Dodge, M. R., Shioda, Tatsutoshi, Rosenblatt, Charles, Parker, Dallas, Kim, Julie, Neubert, Mary |
| Předmět: |
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| Zdroj: |
Liquid Crystals; Oct2004, Vol. 31 Issue 10, p1381-1386, 6p |
| Abstrakt: |
Small quantities of the bent-core mesogen P-7PIMB were dissolved in an anticlinic liquid crystal consisting of a mixture of left- and right-handed TFMHPOBC, with enantiomer excess X =0.2. For bent-core concentrations above C =3 wt %, differential scanning calorimetry shows the disappearance of the higher temperature synclinic phase, as well as the appearance of a new peak at a low temperature T c . Polarized infrared absorption measurements indicate that the new DSC peak is due to an orientational transition of the bent-core molecules, analogous to the transition previously observed in a smectic A matrix. For T > T c the plane of the bent-core molecules lies in the tilt plane of the anticlinic matrix, with the arrow (the symmetry axis) of the bent-core molecules parallel to the smectic layers. For T < T c we deduce that the bent-core molecules lie within a single smectic layer, with the polar tilt of the arrow approximately equal to the polar tilt of the TFMHPOBC molecule and the vector connecting the two ends of the bent-core molecule perpendicular to the anticlinic tilt plane. Additionally, T c was found to be an increasing function of bent-core concentration. [ABSTRACT FROM AUTHOR] |
| Databáze: |
Complementary Index |
| Externí odkaz: |
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