Cholesterol-tailored mesogens as halogen bonded thermotropic liquid crystals

• Main Author: Tan, Candice Yar Hui.
• Other Authors: Lu, Xuehong
• Format: Final Year Project
• Language: English
• Published: 2009
• Subjects: DRNTU::Engineering::Materials::Material testing and characterization
• Online Access: http://hdl.handle.net/10356/15433
• Institution: Nanyang Technological University

As hydrogen bonding has long been employed to induce supramolecular assembly in liquid crystals, this research shall instead explore the possibility of using halogen bonding (N-I) as a driving force in inducing molecular ordering in liquid crystals. Characterizations and the structure- property relationships of the complexes formed between azobenzene derivatives as halogen bond donor and 4-iodo-2,3,5,6-tetrafluorophenoxy alkane as acceptor will be examined to justify the theory that the composition of liquid crystalline materials is crucial in predicting its physical properties. The knowledge of the structure- property relationships of hydrogen bonded complexes established in earlier research were also incorporated into this report during the analysis of results. In addition, the strength of the chromophore in the unbounded compounds and complexes will also be examined and FTIR spectroscopy was carried out to prove the existence of halogen bonding in the complexes formed. From the results obtained, there are observations that the formulation of the complex does affect the physical properties of the material and these findings will be discussed in Chapter Four. Although the nematic phase exhibited by the calamitic liquid crystals in this research is the simplest and most technologically valuable phase presently in the display industries, scientists foresee that smectic C* phase will be making its way into displays in the near future.