23. Ordered structure of thermotropic liquid crystalline polymers. 2. Observation of annihilation kinetics of wedge disclinations
			        作者:Toshio Shiwaku, Akemi Nakai, Wei Wang, Hirokazu Hasegawa, Takeji Hashimoto
关键字:hermotropic liquid crystalline copolymer
论文来源:期刊
具体来源:Liquid Crystals
发表时间:1995年
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 and in situ by 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 of D(t) ∼ t0.35  over 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  between s = + 1/2 and s = - 1/2 or between s = + 1 and s = - 1/2 were directly observed in situ by optical microscopy, and the distance between them was observed to decrease with time.