| 초록 |
We have investigated the thermotropic transition of ethyl 4-[4-oxypoly(prolyleneoxy)-propyloxy]-4´-biphenylcarboxyloxy]-4´-biphenylcarboxylate with poly(propylene oxide) coil by using small angle x-ray scattering (SAXS) and differential scanning carlorimetry (DSC). Instead of preparing a number of rod-coil molecule with different repeating units, we fractionated two rod-coil molecules into monodisperse polymers by reversed phase interaction chromatography (RPLC). We confirmed that HPLC fractionated rod-coil molecules are monodisperse by using MALDI-TOF MS. The rod-coil molecules with different coil length exhibited rich self-assembled microstructures. And also dramatic mesophase changes were observed with the variation of the coil length. The rod-coil molecules with short PPO coils (DP=6, 7) displayed layered smectic mesophases, while the rod-coil molecules with medium-length coils (DP = 8, 9, 12, 13, 14) exhibited bicontinuous cubic mesophase with Ia3d symmetry and hexagonal columnar mesophase. Further increasing the length of coils as in the cases of DP = 15, 16, 17 induces face-centered tetragonal structures. From these results a detailed phase diagram of rod-coil molecules was constructed over PPO coil length. |
