Studies on the Formatio Mechamisms and Functionality Properties of Single Crystalline Flims of Ferroelectic Polymers

铁电聚合物单晶薄膜的形成机理及功能特性研究

• 批准号: 08455448
• 负责人: OHIGASHI Hiroji
• 金额: $ 4.74万
• 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: 1996
• 资助国家: 日本
• 起止时间: 1996 至 1997
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-08455448/
• 关键词: Ferroelectric Polymer; Piezoelectric Polymer; Single Crystalline Film; P (VDF; TrFE); Polymer Blend; Moelecular Chain Motion; Ultrasonic Transducer; Electro-optical Effect; X線散浸散乱; P (VDF; 電気光学効果; 複屈折率; 秩序形成

We previously found that ferroelectric copolymer of vinylidene fluoride and trifluoroethylene, P (VDF/TrFE), crystallizes into a highly crystallized, and highly double-oriented film, which we call a single crystalline (SC) film. The SC film is best material to investigate anisotropic properties of polymer crystals, because it do not have amorphous phase nor lamellar crystals. In this research project we have studied (i) the structure of SC film and its formation mechanisms, (ii) the origin of anormalous dielectric behavior apperaring above the Curie temperature, from the standpoint of molecular chain motions in the paraelectric phase, (iii) piezoelectric properties and its application to shear wave ultrasonic transducers, and (iv) electro-optical properties.The results obtained are as follows. (1) The SC film in the orthormbic phase is a twin crystal, whose c-axis orients parallel to the stretching axis, and the b-axis (polar axis) orients 300 off the film normal. In the paraelectric p … More hase it becomes a hexagonal single crystal, the hexagonal [100] axis being normal to the film surface. The preferential orientation of the crystal axes is developed in the paraelectric (hexagonal) phase, which is due to the lowest free surface energy of the (100) plane in the hexagonal phase. (2) The molecular chain motion in the paraelectric phase was revealed by X-ray diffraction and dielectric relaxation measurements : 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. (3) The SC film is found to have very effective shear piezoelectricity. We developed transducers for transverse ultrasonic waves, which have been proved to be practically useful for non-destractive inspection of industrial materials. (4) The electrooptical property (Pockels effect) was measured. The result shows the film to be a potential material for electrooptical devices.In addition to the above mentioned results, we have obtained some useful and interesting results on the structure and properties of oriented films of (a) P(VDF/TrFE)/PMMA blends, (b) high pressure crystallized P(VDF/TrFE)/PVDF and (c) high pressure crystallized polyethylene. Less

我们先前发现偏二氟乙烯和三氟乙烯的铁电共聚物P（VDF/TrFE）结晶成高度结晶且高度双取向的膜，我们称之为单晶（SC）膜。由于SC膜不存在非晶相和层状晶体，是研究聚合物晶体各向异性的最佳材料。在本研究计画中，我们研究了（i）SC薄膜的结构及其形成机制，（ii）从顺电相分子链运动的观点探讨居里温度以上反常介电行为的起源，（iii）压电特性及其在横波超音波换能器上的应用，（iv）电光特性，所得结果如下。(1)正交相的SC膜是孪晶，其c轴平行于拉伸轴取向，并且b轴（极轴）偏离膜法线30 °取向。在顺电p ...更多信息 当它变成六方单晶时，六方[100]轴垂直于膜表面。晶轴的择优取向在顺电（六方）相中发展，这是由于在六方相中（100）平面的最低自由表面能。(2)通过X射线衍射和介电弛豫测量揭示了顺电相中的分子链运动：在具有液晶特性的六方晶体中，TGTG'构象的每个链分子独立于相邻的链分子进行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。(3)SC膜具有非常有效的剪切压电性。我们研制的横向超声波换能器，已被证明是实用的工业材料的无损检测。(4)测量了其电光特性（普克尔斯效应）。除上述结果外，我们还对（a）P（VDF/TrFE）/PMMA共混物，（B）高压结晶P（VDF/TrFE）/PVDF和（c）高压结晶聚乙烯的取向膜的结构和性能进行了研究。少

项目成果

T.Hattori: "Crystallization behaviour and phase diagram of extended chain crystals of poly (vinylidene- fluoride)" Polymer. 37. 85-91 (1996)

T.Hattori：“聚偏二氟乙烯延长链晶体的结晶行为和相图”聚合物。

H.Ohigashi: "Chain Motions in the Paraelectric Phase in Single Crystalline Films of Vinylidene Fluoride and Trifluoroethylene Copolymer P(VDF/TrFE)" J.Phys.Soc.Japan. (掲載予定).

H.Ohigashi：“偏二氟乙烯和三氟乙烯共聚物 P(VDF/TrFE) 单晶薄膜中顺电相的链运动”J.Phys.Soc.Japan（即将出版）。

大東 弘二(分担執筆): "超音波ハンドブック(圧電高分子トランスデューサ)" 丸善出版(出版予定), (1998)

Koji Daito（撰稿人）：《超声波手册（压电聚合物换能器）》丸善出版社（待出版），（1998 年）

Takeshi Hattori: "Improved piezoelectricity in thick lamellar β-form crystals of poly (vinylidene fluoride) crystallized under high pressure" Journal of Applied.Physics. 79. 2016-2022 (1996)

Takeshi Hattori：“高压下结晶的聚偏二氟乙烯厚层状 β 型晶体的压电性得到改善”《应用物理学杂志》79。2016-2022 (1996)

H.Ohigashi: "Structure of Single Crystalline Films of Vinylidene Fluoride and Trifluoroethylene Copolymers" Polymer J. to be submitted.

H.Ohigashi：“偏二氟乙烯和三氟乙烯共聚物的单晶薄膜的结构”Polymer J.待提交。