| 초록 |
Bent main-chain LC polyesters were synthesized from A-B type carboxylic acids. The phase behaviors and structures of these polyesters were characterized using DSC, WAXD, SAED and PLM. 1D WAXD results combined with DSC results revealed that odd-numbered polyesters enter a low-ordered LC phase before developing a crystalline phase while even-numbered polyesters exhibit a low-ordered LC phase and a highly ordered smectic crystal phase before developing a crystalline phase. Even though even-numbered polyesters retain the zigzag molecular arrangement in SmC which mimics the bent-core small molecules, chiral characteristics are not observed. On the other hand, odd-numbered polyesters are more or less parallel to each other along the chain. Therefore, it is concluded that the different structures were attributed to the interplay between the mesogenic group ordering propensity and the chain constraints dictated by the methylene spacer and the meta-linkage at the end of mesogen. |
