2000 Fiscal Year Final Research Report Summary
Molecular theory of composite liquid crystal systems and interfaces
| Project/Area Number |
09650022
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Applied materials science/Crystal engineering
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| Research Institution | Fukui University of Technology |
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Principal Investigator |
KIMURA Hatsuo Fukui University of Technology, Department of Engineering, Professor, 工学部, 教授 (60023032)
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| Project Period (FY) |
1997 – 2000
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| Keywords | mixtures of molecules / molecular composite / polymer liquid crystal / liquid crystal interface / liquid crystal phase transition / transition temperature / transition entropy / head-tail asymmetry |
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| Research Abstract |
The phase transitions (including the melting) in various liquid crystalline composite systems were investigated theoretically. The corelations between the physical properties of the system and the shape and chemical structure of the component parts were studied in detail and many experimental results were disucussed and explained with the theoretical results. The obtained results are useful to molecular designs and predictions of new liquid crystal systems.
The treated systems are (1) mixtures of different molecules, (2) molecules composed of hard-rod like parts and flexible chain-like parts (typical mesogens and various dimers), and (3) polymer liquid crystals of both the main-chain type and side-chain type. For each system, the co-operative corelations between component parts were studied using similar molecular models and unified theoretical methods. The free energy of liquid crystal phase was calculated as function of orientational order parameters of the component parts in the mean field approximation. Theoretical expressions were given using moleculae parameters for the phase trnsition temperatures, transition entropies, Frank elastic constants, etc. (4) The interface between mesogens and polymers was treated as a composit system, and molecular orientations and phase transitions at the interface were discussed in detail. The interfacial tension and anchoring energy were calculated and a memory effect of polymers was discussed. (5) Assuming a head-tail assymmetry of molecules, the succssesive phase transitions in anti-ferroelectric chiral smectic C liquid crystals were studied theoretically and using computer simulations. The theory could explain basically the experimental results of the system.
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