Possible reasons that piezoelectricity has not been found in bulk polymer of polyvinylidene-cyanide

doi:10.1016/j.polymer.2008.03.043

	Possible reasons that piezoelectricity has not been found in bulk polymer of polyvinylidene-cyanide
	Wang, Zhi-Yin 2,3; Su, Ke-He 1; Fan, Hui-Qing 3; Wen, Zhen-Yi 4
刊名	POLYMER
	2008-05-13
卷号	49 页码:2542-2547
关键词	piezoelectricity PVDCN polymer physical chemistry
ISSN号	0032-3861
DOI	10.1016/j.polymer.2008.03.043
英文摘要	The structure, energy, internal rotation, dipole moments and molecular polarizabilities of poly(vinylidene cyanide) (PVDCN) of alpha- and beta-chain models were studied with density functional theory at B3PW91/6-31G(d) level. The effects of chain length on the polymer chain stabilities, chain conformations and electric properties were examined and compared with those of the piezoelectric PVDF in order to explore the possible reasons that the piezoelectricity has not been observed in the bulk polymer of PVDCN experimentally. The results show that the energy barriers (11.5 and 6.9 kJ/mol) of PVDCN in its alpha- -> beta-chain and beta- -> alpha-chain transitions are smaller than those (16.3 and 8.2 kJ/mol) of PVDF, which promises an easier transition between the two conformations. This may be one of the reasons that the preparation of the stable piezoelectric phase will be difficult. However, an extremely important feature of the ideal beta-chain is that the PVDCN chain is curved with a radius of only about 8.5 angstrom, which is much smaller than that (30.0 angstrom) in PVDF and is smaller than that (12.6 angstrom) in polymethylvinylidenecyanide (PMVC). This Suggests that the bulk polymer Of PVDCN is difficult to be prepared into crystal phase, and the contribution of the dipole moment per unit to the total dipole will be cancelled if the chain is longer than 12 units (hemicycle). Therefore, the reasons that the piezoelectricity has not been found may be due to the Orientation difficulties of chains and dipoles. (c) 2008 Elsevier Ltd. All rights reserved.
WOS关键词	DENSITY-FUNCTIONAL THEORY ; VINYL-ACETATE COPOLYMER ; FLUORIDE-TRIFLUOROETHYLENE COPOLYMERS ; PHASE-TRANSITION ; POLY(VINYLIDENE FLUORIDE-TETRAFLUOROETHYLENE) ; FERROELECTRIC TRANSITION ; ELECTRIC PROPERTIES ; CO-POLYMERS ; FILMS ; PYROELECTRICITY
WOS研究方向	Polymer Science
语种	英语
出版者	ELSEVIER SCI LTD
WOS记录号	WOS:000256131300017
内容类型	期刊论文
源URL	[http://119.78.100.186/handle/113462/29316]
专题	中国科学院近代物理研究所
通讯作者	Su, Ke-He
作者单位	1.NW Polytech Univ, Sch Nat & Appl Sci, Xian 710072, Shaaxi, Peoples R China 2.Shaanxi Univ Technol, Sch Chem & Environm Sci, Hanzhong 723000, Shaaxi, Peoples R China 3.NW Polytech Univ, Sch Mat Sci & Engn, State Key Lab Solidificat Proc, Xian 710072, Shaaxi, Peoples R China 4.NW Univ Xian, Inst Modern Phys, Xian 710068, Shaaxi, Peoples R China
推荐引用方式 GB/T 7714	Wang, Zhi-Yin,Su, Ke-He,Fan, Hui-Qing,et al. Possible reasons that piezoelectricity has not been found in bulk polymer of polyvinylidene-cyanide[J]. POLYMER,2008,49:2542-2547.
APA	Wang, Zhi-Yin,Su, Ke-He,Fan, Hui-Qing,&Wen, Zhen-Yi.(2008).Possible reasons that piezoelectricity has not been found in bulk polymer of polyvinylidene-cyanide.POLYMER,49,2542-2547.
MLA	Wang, Zhi-Yin,et al."Possible reasons that piezoelectricity has not been found in bulk polymer of polyvinylidene-cyanide".POLYMER 49(2008):2542-2547.