Experimental Characterization and Model Validation of Smart Piezoelectric Nanocomposites using Ultramicrotome

我们目前的NSERC DG赞助的研究计划涉及智能压电纳米复合材料（SPNC）的机电行为的准确建模和实验表征，该复合材料含有由氧化锌和氮化镓制成的活性压电纳米线（NW）。SPNC将成为下一代轻质纳米结构复合材料的基础，适用于需要多功能，自主性和适应性的应用，涉及传感器，执行器和能量采集器。我们研究计划的一个重要方面是评估NW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联的复杂性。在这个RTI中，我们正在寻求支持，以获得一个超薄切片机系统能够制备纳米复合材料样品的显微镜表征。这些样品是具有所需几何形状、厚度、平整度和粗糙度的带的形式，这些形状、厚度、平整度和粗糙度是一致的，并且符合非常严格的公差（<1 nm）。这些拓扑特征不能通过诸如抛光的特别方法获得。所提出的系统配备了一个全机动化的阶段，必要的控制和精确的玻璃和金刚石刀，使其能够接受广泛的基板，并一致地生产色带，而不会扭曲或拉动纳米线。它动态隔离环境振动，消除了由于空气阻力引起的厚度变化。为了避免设备的不必要重复，我们对UofT和附近机构的现有超微切片机进行了广泛的搜索。我们的研究表明，现有的超微切片机专门用于组织工程，生物，化学和医学应用。因此，这些设施中的大多数已经配置了它们的系统，使得它们不适合切片纳米复合材料样品。此外，这些系统完全忙于自己的研究团队和/或外部合同。 鉴于我们压电研究的高度专业性，有必要在专用设施中制备样品，以确保其适用于我们的应用和HQP的适当培训。所要求的超薄切片机将显著提高我们高效、一致地制备样品的能力，以获得高质量的图像，最终获得准确和有意义的结果。由拟议的超薄切片机支持的研究将有助于开发创新和具有成本效益的SPNC，大大提高了对其行为的理解，有关压电系数实验表征的新知识，以及在本研究计划的5年期间对66名HQP进行有效培训。鉴于超薄切片机系统的重要性，本署将拨款12，000元，支持拟议的超薄切片机系统。

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.