新型非旋光性彎曲型液晶合成與探討

Systhesis and Characterization of Achiral Novel Bent-Core Liquid Crystals

本研究目的為合成新型彎曲型液晶，其核心結構為 3, 4 位置雙苯環（3,4′-biphenyldiol），並於核心結構加上取代基（氟或氯），觀察對液晶相轉移行為所造成的影響並加以探討。然而，本結構的彎曲型液晶可破壞分子間的堆疊進而降低熔點並利用苯環上的取代基增大極化值，使分子與分子間的作用力上升增加液晶相溫度範圍。相較於以往之彎曲型液晶的SmCP相，本結構具有較低的澄清點溫度與穩定的層列型液晶相（smectic CP, SmCP）。液晶相特性的研究方法可經由偏光顯微鏡（polarizing optical microscope,POM）、示差掃瞄式卡計（differential scanning calorimeter, DSC）、X光射線繞射儀（X-ray diffractometer, XRD）以及光電量測等來進行研究。

The purpose of this study was to design the synthesis of new bent-coreliquid crystals, with core structures of 3, 4-position pairs of benzene rings(3,4′-biphenyldiol), and core structures with substituents (fluorine or chlorine),to observe the behavior of the liquid crystal phase transfer impact.However, the structure of bent-core molecules can damage the stackand thus reduce the melting point and the use of benzene ring substituentscan increase polarization, so that the force between molecules becomeslarger vaises the liquid crystal phase temperature range. Compared to thetraditional bent-core liquid crystals SmCP phase, the structures of thesecrystals have lower clear points and less SmCP phase stability.The characteristics of liquid crystal phases were studied by polarizingoptical microscopy, differential calorimetry, X-ray diffraction and electroopticalmethods.