Experimental Characterization and Model Validation of Smart Piezoelectric Nanocomposites using Ultramicrotome

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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.