Electrostatic-field-induced chain alignment of liquid crystalline copolyether TPP thin films

	Electrostatic-field-induced chain alignment of liquid crystalline copolyether TPP thin films
	Xie FC ; Hu ZJ ; Liu JP ; Yang XN ; Yan DH ; He TB ; Zheng RQ ; Cheng SZD ; Percec V
刊名	polymer
	2001
卷号	42 期号:9 页码:4039-4044
关键词	ORDERED MESOPHASE STRUCTURES PHASE IDENTIFICATION ELECTRIC-FIELD POLYETHERS SERIES ORIENTATION EVOLUTION UNITS
ISSN号	0032-3861
通讯作者	he tb
中文摘要	a liquid crystalline (lc) copolyether has been synthesized from 1-(4-hydroxy-4'-biphenyl)-2-(4-hydroxyphenyl)propane with 1,7-dibromoheptane and 1,11-dibromoundecane with a 50/50 (both in %) equal composition of the 7- and 11-methylene monomers [cotpp-7/11(5/5)]. a mono-domain with a homeotropic alignment can be induced by a thin film surface in the lc phase. when an electrostatic field is applied to the surface-induced mono-domains parallel to the thin film surface normal, the molecular alignment undergoes a change from the homeotropic to uniaxial homogeneous arrangement. however, when the field is applied to a direction perpendicular to the thin film surface normal. the molecular alignment is about 10 degrees -tilt with respect to the homeotropic alignment toward the a*-axis. this is because the permanent dipole moment of the copolyether is not right vertical to the molecular direction. the calculation of molecular dipoles indicates that the permanent dipole moment of this copolyether is about 70 degrees away from the molecular axis, which leads to a negative dielectric anisotropy. it is speculated that the 10 degrees- rather than 20 degrees -tilt is due to a balance between the alignment induced by the electrostatic field and the surface. in the electrostatic field, molecules are subjected to a torque tau, which is determined by the permanent dipole moment p and the electrostatic field e: tau = p x e. the molecular realignment in both parallel and perpendicular directions to the thin film surface normal is determined by satisfying the condition of tau = p x e = 0. (c) 2001 elsevier science ltd. all rights reserved.
收录类别	SCI收录期刊论文
语种	英语
WOS记录号	WOS:000167050400011
公开日期	2010-11-04
内容类型	期刊论文
源URL	[http://202.98.16.49/handle/322003/20945]
专题	长春应用化学研究所_长春应用化学研究所知识产出_期刊论文
推荐引用方式 GB/T 7714	Xie FC,Hu ZJ,Liu JP,et al. Electrostatic-field-induced chain alignment of liquid crystalline copolyether TPP thin films[J]. polymer,2001,42(9):4039-4044.
APA	Xie FC.,Hu ZJ.,Liu JP.,Yang XN.,Yan DH.,...&Percec V.(2001).Electrostatic-field-induced chain alignment of liquid crystalline copolyether TPP thin films.polymer,42(9),4039-4044.
MLA	Xie FC,et al."Electrostatic-field-induced chain alignment of liquid crystalline copolyether TPP thin films".polymer 42.9(2001):4039-4044.