Density functional theory study of the structure and electric properties of poly(vinylidene cyanide trifluoroethylene) copolymer ultrathin film

doi:10.1016/j.synthmet.2010.09.009

	Density functional theory study of the structure and electric properties of poly(vinylidene cyanide trifluoroethylene) copolymer ultrathin film
	Wang, Zhi-Yin 1,3; Su, Ke-He 2; Wang, Fang 4; Wen, Zhen-Yi 5
刊名	SYNTHETIC METALS
	2010-11-01
卷号	160 页码:2341-2350
关键词	Polymer physical chemistry Structure-property relations P(VDCN-TrFE) Density functional theory
ISSN号	0379-6779
DOI	10.1016/j.synthmet.2010.09.009
英文摘要	The geometry, energy, internal rotation barrier, vibrational spectra, dipole moments and molecular polarizabilities of poly(vinylidene cyanide-trifluoroethylene) (P(VDCN-TrFE)) of alpha- and beta-chain models were studied with density functional theory at B3PW91/6-31G(d) level. The effects of chain length and the trifluoroethylene (TrFE) content on the copolymer chain stabilities, chain conformations, electric properties and vibrational spectra were examined and compared with those of the poly(vinylidene fluoride-trifluoroethylene) (P(VDF-TrFE)) copolymer and the polyvinylidene cyanide (PVDCN) homopolymer to explore whether the ultrathin film of P(VDCN-TrFE) possess an expected good piezoelectricity or not. Based on the internal rotation potential curves of P(VDCN-TrFE) dimer models (H(CH2C(CN)(2)-CFHCF2)H and H(C(CN)(2)CH2-CF2CFH)H), the conformational angles, relative stabilities of alpha- and beta-conformations and the transition energy barriers of beta ->alpha and alpha ->beta were discussed. The results show that the beta-conformation is more stable than the alpha-conformation and the beta ->alpha transition in P(VDCN-TrFE) is more difficult than that in PVDCN. The energy difference per monomer unit between beta- and alpha-chain P(VDCN-TrFE) copolymers with a variety of TrFE contents is smaller than that in PVDCN homopolymer, suggesting that alpha ->beta conformational change would be easier in the copolymer than in the homopolymer. The ideal beta-chain of P(VDCN-TrFE) alternate copolymer with 50 mol% TrFE has a radius of about 16 angstrom, which is almost twice as large as PVDCN (8.5 angstrom) and the dipole moment contribution per monomer unit in the copolymer is even larger than the alternate P(VDF-TrFE) copolymer. The energy difference per monomer unit between the beta- and alpha-chains decreases with increasing TrFE content. The contribution of average dipole moment per monomer unit in the beta-chain is affected by the chain curvature and TrFE content, and there is a parabolic dependence on the VDCN content. The mean polarizability decreases with increasing TrFE content slightly. This work also predicted that there are some characteristic vibrational modes that may be used in identification of the alpha- and beta-P(VDCN-TrFE) with different TrFE content. (C) 2010 Elsevier B.V. All rights reserved.
资助项目	Shaanxi Province Education Ministry Research Foundation[08JK242] ; Shaanxi University of Technology[SLGQD0709]
WOS关键词	FERROELECTRIC PHASE-TRANSITION ; VINYL-ACETATE COPOLYMER ; SINGLE-CRYSTALLINE FILMS ; ATOMIC-FORCE MICROSCOPY ; OLIGOMER THIN-FILMS ; X-RAY-DIFFRACTION ; POLYVINYLIDENE FLUORIDE ; DIELECTRIC-RELAXATION ; PIEZOELECTRIC PROPERTIES ; COMPUTER-SIMULATION
WOS研究方向	Materials Science ; Physics ; Polymer Science
语种	英语
出版者	ELSEVIER SCIENCE SA
WOS记录号	WOS:000284815400019
资助机构	Shaanxi Province Education Ministry Research Foundation ; Shaanxi University of Technology
内容类型	期刊论文
源URL	[http://119.78.100.186/handle/113462/32283]
专题	中国科学院近代物理研究所
通讯作者	Wang, Zhi-Yin
作者单位	1.Shaanxi Univ Technol, Sch Chem & Environm Sci, Hanzhong 723000, Shaanxi, Peoples R China 2.NW Polytech Univ, Sch Nat & Appl Sci, Xian 710072, Shaanxi, Peoples R China 3.NW Polytech Univ, State Key Lab Solidificat Proc, Sch Mat Sci & Engn, Xian 710072, Shaanxi, Peoples R China 4.Shaanxi Inst Educ, Dept Chem, Xian 710061, Shaanxi, Peoples R China 5.Northwest Univ, Inst Modern Phys, Xian 710068, Shaanxi, Peoples R China
推荐引用方式 GB/T 7714	Wang, Zhi-Yin,Su, Ke-He,Wang, Fang,et al. Density functional theory study of the structure and electric properties of poly(vinylidene cyanide trifluoroethylene) copolymer ultrathin film[J]. SYNTHETIC METALS,2010,160:2341-2350.
APA	Wang, Zhi-Yin,Su, Ke-He,Wang, Fang,&Wen, Zhen-Yi.(2010).Density functional theory study of the structure and electric properties of poly(vinylidene cyanide trifluoroethylene) copolymer ultrathin film.SYNTHETIC METALS,160,2341-2350.
MLA	Wang, Zhi-Yin,et al."Density functional theory study of the structure and electric properties of poly(vinylidene cyanide trifluoroethylene) copolymer ultrathin film".SYNTHETIC METALS 160(2010):2341-2350.