LIQUID-CRYSTALLINE ASSEMBLY OF A DIBLOCK ROD-COIL POLYMER-BASED ON POLY(ETHYLENE OXIDE) AND ITS COMPLEXES WITH LICF3SO3

The rod-coil polymer of ethyl xy-4-biphenylylcarbonyloxy]-4'-biphenylc arboxylate with poly(ethylene oxide) with a degree of polymerization o f 12 (12-4) was observed to exhibit a microphase-separated lamellar st ructure with nanoscale dimension and to melt into a layered smectic A mesophase. The complexes of 12-4 with 0.05-0.8 mol of LiCF3SO3 per eth ylene oxide unit of a molecule were also prepared in order to investig ate mesomorphic phase changes of 12-4 upon complexation. An abrupt mes ophase change was observed for the entire range of salt concentrations . The complexes with 0.05-0.2 mol of LiCF3SO3 display an enantiotropic smectic A phase as their highest temperature mesophase. From the comp lex with 0.2 mol of LiCF3SO3, an enantiotropic cubic phase is induced and a smectic A phase disappears at the complex with 0.25 mol of LiCF3 SO3, which displays a cubic mesophase only. The complex with 0.3 mol o f LiCF3SO3 also exhibits an enantiotropic cubic phase; however, it exh ibits a cylindrical micellar mesophase as its highest temperature meso phase, contrary to the complexes with up to 0.25 mol of LiCF3SO3. The complexes with 0.4-0.7 mol of LiCF3SO3 exhibit only a cylindrical mice llar mesophase, and the complex with higher salt concentration becomes amorphous. These results, characterized by a combination of different ial scanning calorimetry, optical polarized microscopy, and X-ray scat tering experiments, are discussed.