Abstract
| Language | English |
|---|---|
| Pages | 031703 |
| Journal | Physical Review E: Statistical Physics, Plasmas, Fluids, and Related Interdisciplinary Topics |
| Volume | 83 |
| Issue number | 3 |
| Publication status | Published - 2010 |
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Unconventional ferroelectric behavior in nanosegregating liquid crystals with de Vries-like behavior. / Nonnenmacher, D.; Osipov, M.A.; Roberts, J.C.; Lemieux, R.C.; Giesseimann, F.
In: Physical Review E: Statistical Physics, Plasmas, Fluids, and Related Interdisciplinary Topics , Vol. 83, No. 3, 2010, p. 031703.Research output: Contribution to journal › Article
TY - JOUR
T1 - Unconventional ferroelectric behavior in nanosegregating liquid crystals with de Vries-like behavior
AU - Nonnenmacher, D.
AU - Osipov, M.A.
AU - Roberts, J.C.
AU - Lemieux, R.C.
AU - Giesseimann, F.
PY - 2010
Y1 - 2010
N2 - Two nanosegregating siloxane-terminated mesogens with chiral (S,S)-2,3-epoxyoctyloxy side chains (E6, E11 )have been synthesized. These compounds form chiral SmA∗ and SmC∗ phases and show an untypical behavior of the spontaneous polarization which increases with decreasing temperature in a convex manner while the tilt angle saturates. We compare these results with results obtained for two similar mesogens with chiral (R,R)-2,3-difluorooctyloxy side chains (F6, F11), which both show a typical concave curvature with decreasing temperature. A theoretical explanation is given for the unexpected temperature dependency of the spontaneous polarization. The materials also exhibited first-order SmC∗-SmA∗ phase transitions and hence, very high values of the tilt angle. All substances show increased de Vries character in the range of 50%, which is substantially higher than 20% for the nonsiloxane analogs. Furthermore, for the latter materials, second-order phase transitions are common, while the siloxane materials exhibit first-order SmA∗-SmC∗ phase transitions. These results clearly suggest that the achievement of nanosegregation is a powerful tool to induce de Vries behavior and to promote first-order SmA∗-SmC∗ phase transitions.
AB - Two nanosegregating siloxane-terminated mesogens with chiral (S,S)-2,3-epoxyoctyloxy side chains (E6, E11 )have been synthesized. These compounds form chiral SmA∗ and SmC∗ phases and show an untypical behavior of the spontaneous polarization which increases with decreasing temperature in a convex manner while the tilt angle saturates. We compare these results with results obtained for two similar mesogens with chiral (R,R)-2,3-difluorooctyloxy side chains (F6, F11), which both show a typical concave curvature with decreasing temperature. A theoretical explanation is given for the unexpected temperature dependency of the spontaneous polarization. The materials also exhibited first-order SmC∗-SmA∗ phase transitions and hence, very high values of the tilt angle. All substances show increased de Vries character in the range of 50%, which is substantially higher than 20% for the nonsiloxane analogs. Furthermore, for the latter materials, second-order phase transitions are common, while the siloxane materials exhibit first-order SmA∗-SmC∗ phase transitions. These results clearly suggest that the achievement of nanosegregation is a powerful tool to induce de Vries behavior and to promote first-order SmA∗-SmC∗ phase transitions.
UR - http://link.aps.org/doi/10.1103/PhysRevE.82.031703
M3 - Article
VL - 83
SP - 031703
JO - Physical Review E
T2 - Physical Review E
JF - Physical Review E
SN - 1539-3755
IS - 3
ER -