1990 Fiscal Year Final Research Report Summary
Structure and Its Control in Ferroelectric Liquid Crystals
| Project/Area Number |
01460073
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| Research Category |
Grant-in-Aid for General Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Research Field |
Applied materials
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| Research Institution | Tokyo Institute of Technology |
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Principal Investigator |
FUKADA Atsuo Professor Tokyo Institute of Technology, Faculty of Engineering, 工学部, 教授 (10013484)
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| Co-Investigator(Kenkyū-buntansha) |
OUCHI Yukio Research Associate Tokyo Institute of Technology, Faculty of Engineering, 工学部, 助手 (60194081)
TAKEZOE Hideo Associate Professor Tokyo Institute of Technology, Faculty of Engineering, 工学部, 助教授 (10108194)
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| Project Period (FY) |
1989 – 1990
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| Keywords | Ferroelectric Liquid Crystals / Antiferroelectric Liquid Crystals / Chiral Smectic C / Electric-field-induced Phase Transition / Tristable Switching / Smectic Layer Switching / Chevron Layer Structure / X-ray Diffraction |
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| Research Abstract |
For the purpose of clarifying the switching mechanism in ferroelectric and antiferroelectric liquid crystals, a PSPC system and a temperature-controlled oven purchased as main equipments in this project have been installed properly, facilitating the accurate X-ray diffraction experiments under an electric field with reasonable reproducibility. By using X-ray diffraction together with polarizing optical microscope observation, the structure of smectic layers as well as directors has been studied in detail.
(1) A quasi-bookshelf layer structure is spontaneously formed at room temperature due to a unique temperature dependence of the interlayer spacing in a mixture composed of naphthalene-derived liquid crystals, though the director tilt angle determined optically shows ordinary temperature dependence and attains a relatively large value, 17^0. (Jpn. J. Appl. Phys. 29 (1990) L984-L986 and Mol. Cryst. Liq. Cryst. (1991) in print)
(2) The field-induced antiferro-ferroelectric phase transition
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is accompanied by reversible smectic layer switching. A layer structure without any electric field application is of chevron as in ordinary SmC*. After the application of a field, the field-induced bookshelf structure relaxes to an obtuse chevron. (Jpn. J. Appl. Phys. 29 (1990) L111-L114)
(3) There exist two components, fast and slow, in the transmittance change due to the phase transition from antiferroelectric SmC^A* to ferroelectric SmC*. The fast component is due to the pretransitional effect. The movement of the domain boundaries is responsible for the slow component. (Jpn. J. Appl. Phys. 29 (1990) L107-L110)
(4) The first-order phase transition between paraelectric SmA and anteferroelectric SmCA* is observed in a flourine containing phenyl pyrimidine derivative, TFMHPDOPB. By racemizing the compound, the first-order phase transition occurs between SmA and SmC* the smectic layer spacing clearly depends on the enantiometric excess even in SmA (Jpn. J. Appl. Phys. 30 (1991) submitted) Less
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