EFFECT OF SMECTOGENICITY OF THE IONIC GROUPS ON THE THERMOTROPIC LIQUID-CRYSTALLINE BEHAVIOR OF PYRIDINIUM AND POLY(4-VINYLPYRIDINIUM) SALTS QUATERNIZED WITH MESOGENIC GROUPS
C. Chovino et al., EFFECT OF SMECTOGENICITY OF THE IONIC GROUPS ON THE THERMOTROPIC LIQUID-CRYSTALLINE BEHAVIOR OF PYRIDINIUM AND POLY(4-VINYLPYRIDINIUM) SALTS QUATERNIZED WITH MESOGENIC GROUPS, Journal of polymer science. Part A, Polymer chemistry, 35(13), 1997, pp. 2569-2577
In order to demonstrate the important smectic power of the ionic funct
ions present in mesogenic molecules, a series of N-alkylpyridinium bro
mides omega-substituted with (4-cyanobiphenylyl) oxy or [4-(2-methyl-1
-butoxy) biphenylyl] oxy mesogenic group and their analogous 4-vinylpy
ridinium polymers were synthesized and characterized. The liquid cryst
alline behavior was studied by differential scanning calorimetry, pola
rizing optical microscopy, and X-ray diffraction. Smectic mesophases,
namely A, B, and E, were identified for the low molecular weight compo
unds, whereas smectic A and E mesophases were identified for the analo
gous polymers. Both structures were found to be very similar. They con
sist of single layers of upright molecules laterally arranged head-to-
tail; the polymer backbone is inserted in between the layers. The mono
layer smectic ordering observed in spite of the presence of the intera
cting cyano and chiral groups demonstrates the prevailing effect of th
e electrical interactions upon the structural organization. (C) 1997 J
ohn Wiley & Sons.