Ferroelectricity in Langmuir-Blodgett Polymer Films

这项工作的目的是探索超薄Langmuir-Blodget （LB）聚合物薄膜的铁电态、开关动力学和不寻常的电导开关现象，这些薄膜的厚度从1到100或更多的单层。这些薄膜在非易失性计算机存储器（或数据缓存或数据存储）、非冷却红外成像设备、非线性电容器、热释电传感器或声学换能器等方面具有潜在的应用前景。本研究包括四个相互关联的部分：1)铁电态性质的研究，如相变温度、自发极化、居里常数和介电滞后。2)低维铁电的研究将在薄至单层的薄膜中进行。3)研究了一种与体极化开关密切相关的新型电导开关现象。4) LB铁电聚合物的潜在应用评价。测量技术将包括开关电荷和电流，热释电响应，电导和介电响应作为温度，电场和厚度的函数。这些结果将提供对聚合物和降维系统中铁电态的前所未有的理解，并将揭示电导开关现象的显著特征。研究结果还将为这些廉价但多功能的电子材料在计算机和传感器技术中的潜在应用提供关键基础。＊＊＊

9616246 Ducharme The purpose of this work is to explore the ferroelectric state, switching dynamics, and an unusual conductance switching phenomenon in ultrathin Langmuir-Blodget (LB) polymer films with thicknesses ranging from one to 100 or more monolayers. These films have potential application to nonvolatile computer memory (or data caching or data storage), uncooled infrared imaging devices, nonlinear capacitors, pyroelectric sensors, or acoustic transducers, among other possibilities. The proposed research has four interrelated components: 1) Investigation of Ferroelectric State properties such as the phase transition temperature, spontaneous polarization, Curie constant, and dielectric hysteresis. 2) Study of Low-Dimensional Ferroelectricity will be in films as thin as one monolayer. 3) Study of a novel conductance Switching phenomenon that intimately connected to bulk polarization switching. 4) Evaluation of Potential Applications uniquely suited to the LB ferroelectric polymers. Measurement techniques will include switching charge and current, pyroelectric responqe, conductance, and dielectric response as functions of temperature, electric field, and thickness. The results will provide unprecedented understanding of the ferroelectric state in polymers and in reduced-dimensionality systems and will reveal the salient features of the conductance switching phenomenon. The results will also provide a critical foundation for potential application of these inexpensive but versatile electronic materials to computer and transducer technologies. ***