| Popis: |
The phase behavior for three binary liquid crystalline systems has been explored. All three contained the room-temperature nematic, 4-4'-n-pentylcyanobiphenyl (K15), as one of their components. K15 has a T KN of 22.3 o C and a T NI of 35.1 o C. The second component for each system is a member of the homologous series 4-[4-alkylcyclohexyl]cyanophenyl. The n-ethyl (S1236), n-butyl (S1188) and n-heptyl (S1115) members of this series were chosen. The eutectic composition of all three systems was found to occur at ≃60 mole % K15. The nematic range of the eutectic composition for the S1236/K15, S1188/K15 and the S1115/K15 system is 16, 27 and >40 o C, respectively. The Schroder-van Laar (S-vL) equation was found to be useful in predicting the eutectic composition for each binary system. The K15/S1236 phase diagram shows a new phase between 10 and 62 mole % K15. This phase is believed to be a co-smectic |
