Smectic C to cubic phase transition of 4'-n-docosyloxy-3'-nitrobiphenyl-4-carboxylic acid (ANBC-22) and alternating-current electric field effect.
Smectic C (SmC) to cubic (Cub) phase transition behavior of 4'-n-docosyloxy-3'-nitrobiphenyl-4-carboxylic acid (ANBC-22) and alternating-current (AC) electric field effect on the SmC phase were examined. The most important and unexpected finding is that even at a temperature 8 K below the zero-field SmC to Cub phase transition temperature (T(SmC-Cub) approximately 408 K) determined previously for the compound and without field, the Cub phase growth occurs, after a very long induction period of several hours. The X-ray diffraction measurements revealed the formation of an Im3m-type Cub phase at the temperature. It is suggested that the "true" transition temperature, which is difficult to determine precisely, exists around 396 K. The time-dependence of the Cub phase growth both without field and under field was analyzed using the well-known Avrami equation, implying the nucleation and growth mechanism mainly operating in the SmC to Cub phase transformation. The fact uncovered is that between 408 and 396 K, the SmC to Cub transformation is virtually prohibited by the strongly limited nucleation. It is concluded that the effect of the electric field on the transition is to promote the nucleation of the Cub phase in the temperature region where the Cub phase is potentially more stable than the precursory SmC phase.
Kutsumizu
Shoichi
S
Department of Chemistry, Faculty of Engineering, Gifu University, 1-1 Yanagido, Gifu 501-1193, Japan. kutsu@gifu-u.ac.jp
Hosoyama
Kouhei
K
Yamada
Makoto
M
Tanaka
Katsufumi
K
Akiyama
Ryuichi
R
Sakurai
Shinichi
S
Funai
Eiji
E