Synthesis and characterization of chiral smectic side‐chain liquid crystalline polysiloxanes and ionomers containing sulfonic acid groups

The synthesis of new chiral smectic A (S A ) side‐chain liquid crystalline polysiloxanes (LCPs) and ionomers (LCIs) containing 4‐allyloxy‐benzoyl‐4‐( S ‐2‐ethylhexanoyl) p ‐benzenediol bisate (ABB) as mesogenic units and 4‐[[4‐(2‐propenyloxy)phenyl]azo]benzenesulfonic acid (AABS) as nonmesogenic units is presented. The chemical structures of the monomers and polymers are confirmed by FTIR spectroscopy or 1 H–NMR. Differential scanning calorimetry (DSC), optical polarizing microscopy, and X‐ray diffraction measurements reveal that all the polymers P I –P IV and ionomers P V –P VI exhibit S A texture. The results seem to demonstrate that the tendency toward the S A ‐phase region increases with increasing sulfonic acid concentration, and the thermal stability of the S A phase is determined by the flexibility of the polymer backbones and the interactions of sulfonic acid groups. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 80: 2335–2340, 2001