By introducing an oleyl group at
the end of the straight rodlike
molecule, the effect of the tail shape on the liquid crystallinity,
biaxiality, and lateral switching behavior of the smectic A phase
was investigated. Three types of molecules possessing a fluorinated
phenyl (pentafluorophenyl, 2,3,4-trifluorophenyl, or 2,3-difluorophenyl)
group and a cis-octadec-9-enyl group were synthesized,
and their liquid crystallinities were compared with the corresponding
molecules with a straight alkyl (trans-octadec-9-enyl
or n-octadecanyl) group. In switching experiments,
the molecules with a bent terminal chain showed higher spontaneous
polarization (P
s) values than those with
a straight terminal chain. Further, the directional changes of the
long molecular axes were suppressed for the molecules possessing a
bent terminal chain. These results show that the introduction of a
bent terminal chain is highly effective for stabilizing ferroelectric
switching behaviors.