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 p olysiloxanes (LCPs) and ionomers (LCIs) containing 4-allyloxy-benzoyl-4-(S- 2-ethylhexanoyl) p-benzenediol his ate (ABB) as mesogenic units and 4-[[4-( 2-propenyloxy)phenyl] azo]benzensulfonic acid (AABS) as nonmesogenic units is presented. The chemical structures of the monomers and polymers are conf irmed by FTIR spectroscopy or H-1-NMR. Differential scanning calorimetry (D SC), optical polarizing microscopy, and X-ray diffraction measurements reve al 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 re gion 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. (C) 2001 John Wile y & Sons, Inc.