Study of Bent-Core Molecules toward Blue Phase Liquid Crystals and Hydrogen-Bonded Liquid Crystalline Nanocomposites

• Main Authors: Chiang, I-Hung, 江奕宏
• Other Authors: Lin, Hong-Cheu
• Format: Others
• Language: zh-TW
• Published: 2015
• Online Access: http://ndltd.ncl.edu.tw/handle/34614091910434715311

博士 === 國立交通大學 === 材料科學與工程學系所 === 103 === Bent-core molecules were of achiral bent-core structures and known as specific mesophasic behaviors, molecular biaxiality, spontaneous polarity, and supramolecular chirality. These special structural and electro-optical properties might lead to a lot of applications. Therefore, four hydrogen-bonded (H-bonded) bent-core complexes S1, P1, C4, and P8 with string-, ring-, and cage-like siloxane termini were synthesized and investigated in chapter 2 to reveal the shape and confinement effects of the terminal siloxane groups on the self-assembled behavior of molecular arrangements. In addition, as illustrated in chapter 3, ferroelectric and anti-ferroelectric mesophases were induced via hybrid (C60-based/Si-based) H-bonded bent core LCs, where the complexes (FIAx and FIIAx) are synthesized and reported for the first time. Not only the Ps values were increased, but also the transition temperatures and ranges of the SmCP phases could be reduced and extended respectively in contrasted to the Si-based H-bonded bent core LCs. Compared with reported Au-based/Si-based H-bonded bent core LCs, much higher contents of surface-modified C60 could be miscible in binary LC complexes indicating an effective hybrid method. Finally, in chapter 4, 1,3,4-oxadiazole–based bent core LCs inducing the broad ranged single-component BPIII phase (with ranges of 34 and 7 K for OXD7* and OXD5B7F*, respectively) were synthesized. It is found that HTPs (measured) and molecular biaxialities (calculated) were crucial for BPIII of bent core molecules.