RUI:Dielectric Permittivity and Charge Transport in Electroactive Polymer Nanofibers: Motivating Undergraduates to Pursue Graduate Studies in Materials Science

本项目将采用静电纺丝技术制备电活性聚合物及其复合共混物纳米纤维。PI通过静电纺丝制造聚合物纳米纤维的方法不同于通常使用模板或其他复杂方法的常见方法。电活性聚合物包括那些在室温下表现出导电、半导体和铁电性质的聚合物。这些聚合物纳米纤维中的基本电荷传输机制和电荷存储将通过温度相关的电导率和介电常数测量来研究。纳米纤维本身具有一个限制电荷流动的环境，因此缺陷的存在将导致电荷传输的变化，并为如何最好地制备无缺陷的纳米纤维提供了一个解决方案。本文提出的对导电、半导体和铁电聚合物中电荷传输和电荷存储的更好理解可能会导出到其他具有类似物理性质的大分子中。复合纳米纤维保留了单个组件的特性，因此固有地能够用于多功能设备，从而更加通用。在本研究的基础上，修改实验将被纳入本科生高级实验课程，实现科研与教学的结合。首席研究员（PI）建议使用一种廉价的纤维纺丝技术，即静电纺丝，制备直径约为人类头发千分之一的电活性聚合物纤维。要研究的材料是特殊的聚合物，它们单独能够承载电流或储存电荷，同时重量轻、柔韧、制造成本低。通过将这些聚合物组合成复合材料，一种聚合物的载流能力和另一种聚合物的电荷存储能力将导致更通用的新型材料。制造这种复合材料的纳米纤维是一种新的、未被探索过的材料，而PI的最终目标是制造具有优越性能的设备和传感器。由纳米纤维制成的器件也有望体积小，能耗低。拟议的研究是跨聚合物科学、物理学、纳米科学和电子学的多学科研究，因此给学生一个健全和直接的研究经验，将训练他们的科学方法，并准备他们成为未来的科学家和工程师。该提案还将增加参与科学研究的本科生人数，这些学生来自目前在科学和工程领域代表性不足的群体，并将扩大PI的外展范围，包括国际合作。

TECHNICAL SUMMARYIn this project electrospinning will be used to prepare nanofibers of electroactive polymers and their composite blends. The PI's approach to making polymer nanofibers via electrospinning differs from common approaches that typically use templates or other complex methods. The electro-active polymers include those that exhibit conducting, semiconducting and ferroelectric properties at room temperature. The fundamental charge transport mechanisms and charge storage in these polymer nanofibers will be investigated via temperature-dependent conductivity and dielectric permittivity measurements. Nanofibers naturally possess a confined environment for charge flow, thus the presence of defects will lead to changes in charge transport and provide a handle on how best to prepare defect-free nanofibers. A better understanding of charge transport and charge storage in conducting, semiconducting and ferroelectric polymers as proposed here might then be exported to other macromolecules that exhibit similar physical properties. The composite nanofibers retain the properties of the individual components and are thus inherently capable of being used in devices that are multifunctional and hence more versatile. Modified experiments based on the proposed research will be included into the senior laboratory course for undergraduates, thereby integrating research and education. NON-TECHNICAL SUMMARYThe principal investigator (PI) proposes to prepare fibers of electrically active polymers having a diameter roughly one-one thousandth that of a human hair using an inexpensive fiber-spinning technique called electrospinning. The materials to be studied are special polymers that are individually capable of carrying a current or storing charge while at the same time are light in weight, flexible, and inexpensive to manufacture. By combining these polymers as composites, the current carrying capacity of one together with the charge storage capacity of the other will lead to novel materials that are more versatile. Fabricating nanofibers of such composite materials is new and unexplored, and the PI's ultimate goal is to make devices and sensors with superior properties. Devices fabricated from nanofibers are also expected to be small in size and to consume less power. The proposed research is multidisciplinary across polymer science, physics, nanoscience, and electronics, thus giving students a sound and direct research experience that will train them in the scientific method and prepare them to be future scientists and engineers. This proposal will also increase the number of undergraduate students participating in scientific research from groups currently underrepresented in the fields of science and engineering and will extend the PI's outreach to include an international collaboration.