| Summary: | 碩士 === 大同大學 === 化學工程學系(所) === 96 === The purpose of this research was an attempt to explore the mesophases and election optical properties of chiral liquid crystals derived from (R)-1-butoxy-2-butanol. Two series of chiral liquid crystal materials derived from (S)-butylene oxide reacting, which were designed and synthesized to investigate the mesorphic and electro-optical properties.
The mesomorphic phases and their corresponding transition temperatures were primarily characterized by the microscopic textures and DSC thermograms, and the ferroelectric phases were further identified by the measurements of electric switching behavior and dielectric constant ε'.
The results show that comparing non-fluorinated liquid crystal materials possessing methyl substituent to that possessing ethyl substituent at the asymmetric carbon, the former reduces the formation of ferroelectric phase. Extending phenyl ring to biphenyl ring in the core of the molecules could result in increasing melting point, clear point and thermal stability of mesophases, and changing the formation of ferroelectric SmC* phase from monotropic to enantiontropic mesophase.
The physical measurement show that compound I(m=10, n=1) at room temperature of spontaneous polarization (Ps) of is 5.49 nC/cm2, and the optical tilt angle (θ) values is 4.0°. For Compound II(m=10, n=2), the maximum of Spontaneous polarization (Ps) values is 12.96 nC/cm2, and the maximum number of the optical tilt angle (θ) values is 35°.
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