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

偏氟乙烯和三氟乙烯的铁电共聚物P(VDF/TrFE)是一种高度结晶、高度双取向、无层状晶体的单晶膜。由于SCF具有非常接近于单晶的性质，它是研究铁电聚合物中各种问题的最佳材料，如SCF中有序结构的形成机理、顺电-铁电相变、晶体中的链运动等。在本研究项目中，我们利用X射线衍射、POM、扫描电子显微镜、透射电子显微镜、DSC、压电共振、介电弛豫测量、布里渊散射、核磁共振等技术研究了SCF的高阶结构及其与这些问题相关的各向异性性质。(1)SCF中c轴(链轴)和b轴(极轴)的择优取向发生在顺电相。在超临界流体中，Orthombi…更多的c(110)晶面与薄膜表面严格平行，表明晶面自由能是决定(100)晶面择优取向的重要因素。在顺电相中长时间(如100h)热处理消除了晶体缺陷，使得超临界流体的硬度非常高：我们成功地获得了在10K下杨氏模数高达204 Gpa的自旋超临界流体。(2)通过X射线衍射、介电弛豫测量、核磁共振自旋晶格驰豫和剪切力学性质明确了顺电相中分子链的运动：TGTG构象的每个链分子都经历了独立于相邻链分子的触发器运动和旋转运动，具有液晶特性。基于这些信息，我们建立了一个新的概念来解释顺电相中出现的反常介电性质。布里渊散射也获得了有关相变的有用信息。(3)Sc膜具有良好的剪切压电性。我们开发了横向超声波换能器。它们对工业材料的非破坏性检验很有用。(4)超临界流体具有较大的普克尔效应，可作为电光器件使用。(5)我们在P(VDF/TrFE)/at-PMMA共混物取向膜的结构和性能方面取得了一些有益和有趣的结果。较少

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