Self-assembly of a coil-rod-coil block molecule complexed with LiCF3SO3

Enantiotropic liquid crystalline phases were induced by the complexation of docosyl 4-(4-oxy-4'-biphenylcarbonyloxy)-4'-biphenyl carboxylate, containi ng poly(ethylene oxide) of twelve ethylene oxide subunits, with 0.25 mol of LiCF3SO3 per ethylene oxide unit. The existence of oblique columnar, recta ngular columnar (Col(rec)), and smectic A (SmA) mesophases of this complex was demonstrated by a combination of polarized optical microscopy and X-ray diffraction. This complex was observed to transform from the rectangular c olumnar phase to a lamellar phase on heating. The unusual phase transition behaviour in this complex is believed to originate from the mixing entropy of the added LiCF3SO3. Also, the Col(rec)-SmA phase transition was accompan ied by a change of the packing structure from bilayer to monolayer.