Liquid-crystalline rod-coil polymers based on poly(ethylene oxide)s and the influence of the complexation of LiCF3SO3 on the liquid-crystalline assembly

The synthesis and characterization of rod-coil polymers of ethyl 4'-(4'-oxy-4-biphenylcarbonyloxy)-4-biphenylcarboxylate with poly(ethylene oxide) of three (3-4), seven (7-4), twelve (12-4) and sixteen (16-4) ethylene oxide units, of 4'-(4'-oxy-4-phenylcarbonyloxy)-4-biphenylcarboxylate with poly(ethylene oxide) of sixteen ethylene oxide units (16-3), and of ethyl 4'-oxy-4-biphenylcarboxylate with poly(ethylene oxide) of sixteen ethylene oxide units (16-2) are described. All the rod-coil polymers except 16-2 display a layered smectic mesophase and, in particular, 16-4 shows a microphase-separated morphology. The complexes of 16-4 with up to 0.3 mol of LiCF3SO3 per mol of ethylene oxide units are also prepared. The rod-coil polymer 16-4 exhibits an enantiotropic smectic B (S-E) mesophase. The complexes with 0.05 and 0.1 mol of LiCF3SO3, however, exhibit an enantiotropic smectic A (S-A) mesophase in addition to an S-B phase. In contrast with the complexes with 0.0-0.1 mol of LiCF3SO3, the complexes with 0.2 and 0.3 mol do not exhibit any smectic mesophases; however, they display a cylindrical micellar mesophase.