Studies on the Molecular Chain Motions, the Ordered Structure Formation Process, and Development Mechanisms of Functionality Properties in Single Crystalline Films of Ferroelectic Polymers

铁电聚合物单晶薄膜分子链运动、有序结构形成过程及功能性能发展机制研究

• 批准号: 10450357
• 负责人: OHIGASHI Hiroji
• 金额: $ 6.59万
• 依托单位: Yamagata University
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (B).
• 财政年份: 1998
• 资助国家: 日本
• 起止时间: 1998 至 2000
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-10450357/
• 关键词: Ferroelectric Polymer; P (VDF; TrFE) copolymer; Single crystalline film; Moelecular chain motion; Higher-order structure controll; Elastic properties; Brillouin scattering; Shear-mode ultrasonic transducer; TrFE); 圧電効果; NMR; 高次構造; 誘電緩和; 圧電高分

The single crystalline film (SCF) of ferroelectric copolymer of vinylidene fluoride and trifluoroethylene, P (VDF/TrFE), is a highly crystallized, highly double-oriented, lamellar-crystal-free film. Since the SCF often exhibits theproperties very close to those of a single crystal, it is the best material for investigation of various problems in ferroelecric polymers such as formation mechaisms of ordered structure in SCF, paraelectric-ferroelectric phase transition, chain motions in the cystal, etc. In this research project, we investigate higher-order structure of SCF and its anisotropic properties relevalent to these problems by using various techniques such as X-ray diffraction, POM, SEM, TEM, DSC, piezoelectic resonance, dielectric relaxaton measurements, Brillouin scattering, NMR, etc. The main results obained are as follows. (1) The preferenial orienation of the c-axis (chain axis) and b-axis (polar axis) in the SCF develops in the paraelectric phase. In the SCF, the orthorhombi … More c (110) crystal plane is strictly parallel to the film surface, indicating that the crystal surface free energy is ant essential factor to determine the preferential orientation of hexagonal (100) plane. Annealing in the paraelectric phase for long period (e.g. 100h) eliminates crystal defects, which makes the stiffness of SCF very high : we suceesfully obtained the SCF having Youngs's modulus as high as 204 GPa at 10K.(2) The molecular chain motion in the paraelectric phase is definitely clarified by X-ray diffraction, dielectric relaxation measurements, NMR spin lattice relaxation, and shear mechanical properties : each chain molecule of TGTG' conformation undergoes the flip-flop motion and rotational motion independently of neighboring chain molecules in the hexagonal crystal, a crystal having liquid crystal characteristic. Based on these information we establish to a new concept to explain the anomalous dielectric properties appearing in the paraelectric phase. Useful information on the phase transition has been also obtained by Brillouin scattering. (3) The SC film has effective shear piezoelectricity. We developed transducers for transverse ultrasonic waves. They are useful for non-destractive inspection of industrial materials. (4) The SCF has large Pockels effect, and is potentially useful as electrooptical devices. (5) We have obtained some useful and interesting results on the structure and properties of oriented films of P(VDF/TrFE)/at-PMMA blends. Less

偏氟乙烯-三氟乙烯共聚物P（VDF/TrFE）铁电单晶薄膜是一种高度结晶、高度双取向、无片晶的薄膜。由于超临界流体往往表现出与单晶非常接近的性质，它是研究铁电聚合物中各种问题的最佳材料，如超临界流体中有序结构的形成机理、顺电-铁电相变、晶体中链的运动等。我们利用X射线衍射、POM、SEM、TEM、DSC等技术研究了SCF的高阶结构及其与这些问题相关的各向异性性质，压电共振、介电弛豫测量、布里渊散射、核磁共振等。(1)SCF的c轴（链轴）和b轴（极轴）的择优取向在顺电相发展。在SCF中，orthorhombi ...更多信息 c（110）晶面严格平行于薄膜表面，表明晶体表面自由能是决定六方（100）晶面择优取向的重要因素。在顺电相中长时间退火（如100 h）消除了晶体缺陷，使SCF的刚度非常高：我们成功地获得了在10 K下杨氏模量高达204 GPa的SCF。(2)顺电相中的分子链运动通过X射线衍射、介电弛豫测量、NMR自旋晶格弛豫和剪切力学性质明确地阐明：TGTG'构象的每个链分子独立于六方晶体（具有液晶特性的晶体）中的相邻链分子经历翻转运动和旋转运动。基于这些信息，我们建立了一个新的概念来解释出现在顺电相的反常介电性质。通过布里渊散射也获得了有关相变的有用信息。(3)SC膜具有有效的剪切压电性。我们开发了用于横向超声波的换能器。它们可用于工业材料的无损检测。(4)SCF具有很大的普克尔斯效应，是一种很有潜力的电光器件。(5)我们对P（VDF/TrFE）/at-PMMA共混物取向膜的结构和性能进行了研究，得到了一些有用的结果。少

项目成果

M.A.Barique and H.Ohigashi: "Annealing effects on the Curie transition emperature and melting temperature of poly (vinylidene fluoride/trifluoroethylene) single crystalline films"Polymer. 42. 4981-4987 (2001)

M.A.Barique 和 H.Ohigashi：“退火对聚（偏二氟乙烯/三氟乙烯）单晶薄膜的居里转变温度和熔化温度的影响”聚合物。

Y.Tajitsu, S.Kato, H.Ohigashi, M.Date and E.Fukada: "Complete Pockels tensor component analysis of ferroelectric copolymers of vinylidene fluoride and Trifluoroethylene"J.Materials Sci.Lett.. 19. 295-298 (2000)

Y.Tajitsu、S.Kato、H.Ohigashi、M.Date 和 E.Fukada：“偏二氟乙烯和三氟乙烯铁电共聚物的完整 Pockels 张量分量分析”J.Materials Sci.Lett.. 19. 295-298 (2000)

H.Yasuda and A.Yoshihara: "Elastic constants and surface acoustic waves of superlattices"J.Phys.Condensed Matter. 10. 9623-9634 (1998)

H.Yasuda 和 A.Yoshihara：“超晶格的弹性常数和表面声波”J.Phys.Condensed Matter。

A.Yoshihara, Z.J.Wang, K.Takanashi, P.Gruenberg, M.Motokawa and H.Fujimori: "Spin wave modes in fine layered structures of Fe and Au"J.Magn.Soc.Jpn.. 23. 161-3 (1999)

A.Yoshihara、Z.J.Wang、K.Takanashi、P.Gruenberg、M.Motokawa 和 H.Fujimori：“Fe 和 Au 精细层状结构中的自旋波模式”J.Magn.Soc.Jpn.. 23. 161-3

H.Ohigashi: "Polymer Ultrasonic Transducers"Metals and Technologies. 68 (in Japanese). 680-687 (1998)

H.Obigashi：“聚合物超声波换能器”金属和技术。