Liquid crystalline properties of dissymmetric molecules IV. The substituent effect on thermal properties of nematic and smectic A phases in three aromatic ring systems with ester linkages
M. Duan et al., Liquid crystalline properties of dissymmetric molecules IV. The substituent effect on thermal properties of nematic and smectic A phases in three aromatic ring systems with ester linkages, LIQ CRYST, 27(9), 2000, pp. 1195-1205
This paper describes the effect of substituent and ester linkage on smectic
properties for some derivatives of 4-R-phenyl 4-(4-octyloxybenzoyloxy)benz
oates (1), 4-octyloxyphenyl 4-(4-R-benzyloxy)benzoates (2), 4-(4-octyloxybe
nzoyloxy)phenyl 4-R-benzoates (3), and 4-R-phenyl 4-octyloxyphenyl terephth
alates (4) where R = OCH3, CH3, OC8H17, C8H17, halogens, CF3, OCF3, CN, NO2
, etc. The thermal properties are discussed in terms of the electrostatic n
ature of the substituents and the relative orientation of the ester groups
with respect to both terminal substituents. The substituent effect on the l
ayer structure of the smectic A phase is also examined by means of a small
angle X-ray analysis.