Ordered structure of thermotropic liquid crystalline copolymers 2. Observation of annihilation kinetics of wedge disclinations
作者:
Toshio Shiwaku,
Akemi Nakai,
Wei Wang,
Hirokazu Hasegawa,
Takeji Hashimoto,
期刊:
Liquid Crystals
(Taylor Available online 1995)
卷期:
Volume 19,
issue 5
页码: 679-691
ISSN:0267-8292
年代: 1995
DOI:10.1080/02678299508031084
出版商: Taylor & Francis Group
数据来源: Taylor
摘要:
The isothermal annihilation kinetics of wedge disclinations in the fully liquid crystalline state were investigated using thin film specimens of a thermotropic liquid crystalline copolyester prepared by a solution-cast method. The as-cast films which are vitrified, homogeneous and amorphous were first subjected to a temperature jump to appropriate temperatures and the coarsening of the liquid crystalline texture was observed in real-time andin situby means of optical microscopy and laser light scattering. The experimental results obtained show that, in the early stages, the domain size,D, which is inversely proportional to the square root of the density of disclinations in the sample, approximately obeys a power law ofD(t)∼t0.35over the time scale covered in the experiment. In the later stages, anchoring of some of the disclination lines onto the glass surface and/or formation of crystallites from some sequences of the copolyester having a higher melting point suppress and then pin the annihilation process. The annihilation processes for pairs of wedge disclinations betweens= + 1/2 ands= − 1/2 or betweens= + 1 ands= − 1/2 were directly observedin situby optical microscopy, and the distance between them was observed to decrease with time.
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