Liquid Crystalline Assembly of a Diblock Rod−Coil Polymer Based on Poly(ethylene oxide) and Its Complexes with LiCF₃SO₃

Abstract

The rod−coil polymer of ethyl 4-[4‘-oxy-4-biphenylylcarbonyloxy]-4‘-biphenylcarboxylate with poly(ethylene oxide) with a degree of polymerization of 12 (12-4) was observed to exhibit a microphase-separated lamellar structure 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 ethylene oxide unit of a molecule were also prepared in order to investigate mesomorphic phase changes of 12-4 upon complexation. An abrupt mesophase 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 complex 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 LiCF3SO3, which displays a cubic mesophase only. The complex with 0.3 mol of LiCF3SO3 also exhibits an enantiotropic cubic phase; however, it exhibits a cylindrical micellar mesophase as its highest temperature mesophase, 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 micellar mesophase, and the complex with higher salt concentration becomes amorphous. These results, characterized by a combination of differential scanning calorimetry, optical polarized microscopy, and X-ray scattering experiments, are discussed.

Spontaneous Organization of Supramolecular Rod-Bundles into a Body-Centered Tetragonal Assembly in Coil−Rod−Coil Molecules

“…The X-ray diffraction pattern of 7 in the crystalline state displays three sharp reflections in the spacing ratio of 1:2:3 in the small-angle region, while two sharp reflections are observed in the wide-angle region, indicative of a lamellar structure consisting of microphase-separated crystalline rod domains and the amorphous coil domains. 12 The layer spacing of 38.3 Å corresponds to a rod tilt with the angle of 49°relative to the layer normal, considering the extended molecular length of 58 Å. In the melt state, the small-angle diffraction pattern shows a number of sharp reflections as shown in Figure 2a.…”

Design amphiphilic dipolar π-systems for stimuli-responsive luminescent materials using metastable states

“…The PXRD analysis revealed that 1O was converted to 1O Li (T iso ¼ 120°C) by forming chelation complexes in the TEG moieties ( Supplementary Fig. 7) 35,36 . The interlayer distance was ARTICLE extended from 34.2 Å in 1O to 60.1 Å in 1O Li ; this change could be ascribed to the cancellation of the molecular tilt owing to the loss of the interdigitation of the TEG moieties upon chelation with the salt (Fig.…”

Ionic conductivity probed in main chain liquid crystalline azobenzene polyesters

“…[13][14][15][16][17][18][19] For instance, a rod coil polymer containing PEO upon complexation with LiCF 3 SO 3 exhibited phase transitions from the highly ordered smectic phase followed by cubic and finally cylindrical micellar mesophase upon increasing Li ion salt concentration. 20 However, the PEO-salt complexes have a natural tendency for crystallization, which retards effective ion transport through polymer matrix. The incorporation of PEO into various polymer architectures like copolymers, block copolymers, comb shaped polymers, hyperbranched polymers, etc.…”