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Title page for etd-0723104-105525


URN etd-0723104-105525 Statistics This thesis had been viewed 2283 times. Download 886 times.
Author Zih-Liang Yang
Author's Email Address u8803012@mail.com.tw
Department Chemical Engineering
Year 2003 Semester 2
Degree Master Type of Document Master's Thesis
Language English Page Count 90
Title Synthesis and Properties of Novel Chiral Liquid Crystal Materials with Amide Linkage Group
Keyword
  • chiral liquid crystal material
  • antiferroelectric
  • antiferroelectric
  • chiral liquid crystal material
  • Abstract The purpose of this research work was an attempt to the structure-property correlation in the chiral liquid crystal materials. Four series chiral liquid crystal materials which have an amide linkage were designed and synthesized in order to investigate the effect of the nonchiral peripheral chain length, n, the effect of different linkage group (RCOO- and RO-) and the effect of the different tailed structure on the mesomorphic properties.
    The mesophase and their corresponding transition temperatures of the liquid crystal materials were identified by the polarizing microscopic texture, DSC carlorimetry and the electro-optical measurements. The antiferroelectric phase was further characterized by the polarizing microscopic texture, the switching current behavior and the electro-optical response.
       The compounds of DEnPBNPA (n=7~11, Z=COO) exhibit a phase sequence of Iso-SmA*-SmCA*-Cr in cooling process. All compounds of DEnPBNPA(n=7~11, Z=COO) exhibit the enantiotropic SmA* phase, compounds of DEnPBNPA(n=7, 9, Z=COO) exhibit the enantiotropic SmCA* phase and the compounds of DEnPBNPA(n=8,10,11, Z=COO) exhibit the monotropic SmCA* phase.
       The compounds of DPnPBNPA (n=7~11, Z=COO) exhibit a phase sequence of Iso-SmA*-Cr in cooling process. All compounds of DPnPBNPA (n=7~11, Z=COO) exhibit the enantiotropic SmA* phase. Expect for the compound, DPnPBNPA (n=11, Z=COO), the transition temperature of Iso-SmA* and SmA*-Cr decrease with increasing the aliphatic chain length. And the transition temperature of Iso-SmA* of compounds, DPnPBNPA (n=7~11, Z=COO) appear an odd-even effect.
       The compounds of MPnPBNPA (n=7~11, Z=COO) exhibit a phase sequence of Iso-SmA*-Cr in cooling process. All compounds of MPnPBNPA (n=7~11, Z=COO) exhibit the enantiotropic SmA* phase. The transition temperature of Iso-SmA* of compounds, MPnPBNPA (n=7~11, Z=COO) appear an odd-even effect.
    The compounds of MPnPBNPA (n=10~14, Z=O) exhibit a phase sequence of Iso-SmA*-SmCA*-Cr in cooling process. The compounds of MPnPBNPA (n=10~14, Z=O) exhibit the monotropic SmCA* phase. The temperature range of SmA* decreases with increasing the aliphatic chain length. The temperature range of SmCA* phase increases form n=10 to n=11 and then decreases from n=12 to n=14.
       The maximum Ps values of compounds, DEnPBNPA (n=7~11, Z=COO) are in a range of 178~240nC/cm2 and the maximum tilt angles are in a range of 16° ~19°. The maximum Ps value of compounds, MPnPBNPA (n=11~13, Z=O) are in a range of 160 ~ 222nC/cm2 and the maximum tilt angles are in a range of 26° ~30°. These two series compounds display an ideal double hysteresis loop in SmCA* phase.
    Advisor Committee
  • Shune-Long Wu - advisor
  • Chin-Tsou Kuo - co-chair
  • Jiunn-Yih Lee - co-chair
  • Liang-Jye Yu - co-chair
  • Files indicate access worldwide
    Date of Defense 2004-06-09 Date of Submission 2004-07-23


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