Experimental Characterization and Model Validation of Smart Piezoelectric Nanocomposites using Ultramicrotome

我们目前由NSERC DG赞助的研究计划致力于对含有由氧化锌和氮化镓制成的活性压电纳米线(NW)的智能压电纳米复合材料(SPNC)的机电行为进行精确建模和实验表征。SPNC将为下一代轻质纳米结构复合材料奠定基础，这些复合材料适用于需要多功能、自主性和适应性的应用，涉及传感器、执行器和能源收集器。我们研究计划的一个重要方面是评估NWS和SPNC的机电行为。现有的文献范围有限，相互矛盾。这是由于与压电系数的原子预测和实验测量相关的复杂性。在这项RTI中，我们正在寻求支持，以获得一种能够制备用于显微镜表征的纳米复合样品的超微切片系统。这些样品呈带状，具有所需的几何形状、厚度、平整度和粗糙度，且一致且符合非常严格的公差(&lt；1 nm)。这些拓扑特征不能通过特殊方法(如抛光)获得。拟议的系统配备了一个全电动工作台，配备了必要的控制和精密的玻璃和钻石刀具，使其能够接受广泛的基材，并持续生产丝带，而不会起皱或拉动NWS。它动态隔离环境振动，消除空气湍流引起的厚度变化。为了避免不必要的设备重复，我们对密歇根大学和附近机构现有的超微显微镜进行了广泛的搜索。我们的搜索显示，现有的超微结构专门用于组织工程、生物、化学和医学应用。因此，这些设备中的大多数都配置了使其不适合对纳米复合材料样品进行切片的系统。此外，这些系统都被它们自己的研究团队和/或外部合同所占据。鉴于我们压电学研究的高度专业性，有必要在专门的设施中准备我们的样品，以确保它们适合我们的应用并对HQP进行适当的培训。所要求的超显微切割机将显著增强我们高效和一致地准备样品以获得高质量图像的能力，最终导致准确和有意义的结果。由拟议的超微切割机支持的研究将有助于开发创新和成本效益高的SPNC，极大地提高对它们行为的理解，关于压电系数的实验表征的新知识，以及在本研究计划的5年期间对66名HQP进行有效的培训。鉴于其重要性，我司将捐助12,000美元，以支持拟议的超微切片机系统。

Our current NSERC DG sponsored research program is concerned with the accurate modelling and experimental characterisation of the electromechanical behaviour of smart piezoelectric nanocomposites (SPNCs) containing active piezoelectric nanowires (NWs) made of Zinc Oxide and Gallium Nitride. SPNCs will form the foundation for the next generation of lightweight nanostructured composites for applications requiring multifunctionality, autonomy and adaptability involving sensors, actuators and energy harvesters. An essential aspect of our research program is the evaluation of the electromechanical behaviour of NWs and SPNCs. Existing literature are limited in scope and contradictory. This is due to the complexities associated with the atomistic predictions and experimental measurements of the piezoelectric coefficients. In this RTI, we are seeking support to acquire an ultramicrotome system capable of preparing nanocomposite samples for microscopy characterisation. These samples are in the form of ribbons with the desired geometry, thickness, flatness and roughness that are consistent and conform to very tight tolerances (<1 nm). These topological features cannot be obtained by ad hoc methods such as polishing. The proposed system is equipped with a fully motorized stage with the necessary controls and precise glass and diamond knives that make it possible to accept a wide-range of substrates and consistently produce ribbons without wrinkling or pulling the NWs. It dynamically isolates environmental vibration and eliminates thickness variation due to air turbulences. To avoid unnecessary duplication of the equipment, we conducted an extensive search of existing ultramicrotomes at UofT and nearby institutions. Our search revealed that existing ultramicrotomes are used specifically for tissue engineering, biological, chemical and medical applications. Consequently, most of these facilities have configured their systems which make them unsuitable for sectioning nanocomposites samples. Additionally, these systems are fully occupied with their own research teams and/or external contracts. In view of the highly specialized nature of our piezoelectric research, it is necessary to prepare our samples in a dedicated facility to ensure their suitability for our applications and the proper training of the HQP. The requested ultramicrotome will significantly enhance our ability to efficiently and consistently prepare samples to obtain high quality images, ultimately leading to accurate and meaningful results. Research supported by the proposed ultramicrotome will aid in developing innovative and cost effective SPNCs, greatly improved understanding of their behaviour, new knowledge concerning the experimental characterization of piezoelectric coefficients, and the effective training of 66 HQP over the 5-year duration of this research program. In view of its importance, my department will contribute $12,000 in support of the proposed ultramicrotome system.