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URN etd-0627106-160838 Statistics This thesis had been viewed 2487 times. Download 1102 times. Author Ting-Yi Lee Author's Email Address No Public. Department Chemical Engineering Year 2005 Semester 2 Degree Master Type of Document Master's Thesis Language English Page Count 86 Title Synthesis and Ferroelectric Properties of New Chiral Liquid Crystal Materials Derived from (S)-1-methyl-2-[(2’-methoxy)ethoxy]ethanol Keyword V-shaped switching Ferroelectric Liquid Crystal Chiral Liquid Crystal Chiral Liquid Crystal Ferroelectric Liquid Crystal V-shaped switching Abstract The purpose of this research was an attempt to study the structure-property correlation in the chiral liquid crystal materials. Three homologous series of chiral materials derived from (S)-1-methyl-2-[(2’-methoxy)ethoxy]ethanol were successfully synthesized in order to investigate the effect of the achiral terminal chain, m, and the effect of the lateral substitution group in the core on the mesomorphic properties.
Chiral compounds of I-6(m=9-12) and II-6(m=10-12) revealed SmA* and SmC* phases, and compounds of I-6(m=8) and II-6(m=8, 9) possessed only SmA* phase. The shorter chain compounds (m=8-10) of the third series III-6(m=8-12) displayed no liquid crystal phase while the longer chain compounds (m=11, 12) exhibited SmA* phase. With the increasing achiral terminal chain lengths, m, the clearing point decrease. The materials with lateral 3-chloro substitution in the phenyl ring of core could depress the formation of SmC* phase.
The electro-optical responses of chiral compounds in the SmC* phase displayed typical ferroelectric switching behavior. Compounds of I-6(m=11) and II-6(m=11) displayed V-shaped switching property in the SmC* phase at appropriate frequency and temperature. The maximum Ps values of compounds I-6(m=9-12) are in the range of 2.8-10.0 nC/cm2 and the maximum tilt angles are in the range of 16.5-21.5?. The maximum Ps values of compounds II-6(m=10-12) are in the range of 3.2-8.3 nC/cm2 and the maximum tilt angles are in the range of 17.0-23.0?.
Advisor Committee Shune-Long Wu - advisor
Jin-Jei Wu - co-chair
Jiunn-Yih Lee - co-chair
Wen-Fu Lee - co-chair
Files Date of Defense 2005-06-15 Date of Submission 2006-06-27