Thermal behaviour of the thermotropic cubic mesogen 4'-n-hexadecyloxy-3'-nitrobiphenyl-4-carboxylic acid (ANBC-16) under hydrostatic pressure
| Autor: | Yoji Maeda, Gui-Ping Cheng, Shinichi Yano, Shoichi Kutsumizu |
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| Rok vydání: | 2001 |
| Předmět: | |
| Zdroj: | Liquid Crystals. 28:1785-1791 |
| ISSN: | 1366-5855 0267-8292 |
| Popis: | The phase behaviour of 4'-n-hexadecyloxy-3'-nitrobiphenyl-4-carboxylic acid (ANBC-16) was investigated under hydrostatic pressures up to 200 MPa using high pressure differential thermal analysis. The phase transition sequence crystal 4 (Cr4)-crystal 3 (Cr3)-crystal 2 (Cr2)-crystal 1 (Cr1)-smectic C (SmC)-Cubic (Cub)-smectic A (SmA)-'structured liquid' (I1)-isotropic liquid (I2) was observed for a virgin sample on heating at atmospheric pressure. The stable temperature region of the optically isotropic cubic phase becomes narrower on increasing pressure and disappears at pressures above 65 MPa. The T vs. P phase diagram exhibits the existence of a triple point (65 MPa, 207.6°C) for the cubic phase, a new mesophase (X), and the SmA phase, indicating the upper limit for the cubic phase. The new mesophase, denoted here as X, appears in place of the cubic phase at pressures above 65 MPa. The phase diagram also indicates that the Cr4-Cr3, Cr3-Cr2, and Cr2-Cr1 transition lines merge at about 40-50 MPa and then o... |
| Databáze: | OpenAIRE |
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