Synthesis and Mesogenic Properties of Bent-shaped and Discotic Liquid Crystals Containing 1, 3-Substituted and 1, 3, 5-Substituted Aromatic Ring

• Main Author: 許智雄
• Other Authors: 蔡文亮
• Format: Others
• Language: zh-TW
• Published: 2009
• Online Access: http://ndltd.ncl.edu.tw/handle/00290733952874092584

碩士 === 高雄師範大學 === 化學系 === 97 === Three series of liquid crystal compounds were synthesized to study the influence of the structure of terminal group or substituent group on the mesogenic behavior of calamitic liquid crystals or bent-shaped liquid crystals or discotic liquid crystals.The results of liquid crystal properties are summarized as follows： (1)The compounds of BnOSC3~BnOSC6 all possess smectic A phase. When the cycloalkyl ring is smaller, the liquid crystal molecules except BnOSC6 tent to form nematic phase.They have broader mesogenic temperature range. (2)The compounds of HOSC3、HOSC4、HOSC5 possess only nematic phase. The compound HOSC6 can’t exhibit any mesogenic phase. (3)The compoumds of the series 2 tend to form mesogenic phase easily.They have broader mesogenic temperature range.The compound BMeC3 possess B6 phase, while the compounds BMeC5 and BMeC6 don’t exhibit any mesogenic phase. The mesogenic phase of BMeC4 can’t be identified due to very narrow phase temperature range. (4)Both the compounds BMeC3 and BMenC4 possess the stable mesogenic phase. The compound BMnC4 has an interdigitating structure of smectic phase. The type of smectic phases is still unknown. (5)The compounds of OrthoC11, MetaC10, 345C9, 345C10, 345C11 possess Colh phase, but OrthoC10 exhibit Colr phase. The liquid crystal phase of 345C10 is Colh phase, not ND phase as punblished in the literature.