Year

2020

Degree Name

Doctor of Philosophy

Department

Australian Institute for Innovative Materials

Abstract

Recent development in miniaturize electronic devices with higher computational capabilities and ultra-low power communication technologies involves a tendency toward powering these devices with high energy efficiency, long cycle life, fast and cheap manufacturing and low weight power sources. Mechanical energy harvesters are needed for such diverse applications such as self-powered wireless sensors, structural and human health monitoring systems, and cheaply harvesting energy from human movements. Integration of piezoelectric materials and novel fabrication strategies with conventional textile process established the emergence of wearable technology field which can meet these needs. In particular, fiber-based electronic devices can be integrated into garments with desirable attributes such as flexibility, stretchability, permeability and lightweight. Piezoelectric fibers are an ideal interface platform option between environment, electronic devices and human’s body and polyvinylidene fluoride (PVDF) is highlighted in the wearable technology field due to its good chemical resistance, strength, thermal resistance and stable and large piezoelectric, ferroelectric, and pyroelectric properties. Previous work has shown that PVDF fibers can be integrated into textile based mechanical energy harvesters and have highlighted the potential for further improvement. The current challenges include slow processing, low energy conversion efficiency and difficulty in integrating the fibers (and associated interconnecting electrodes) into textile garments. Therefore, the aim of this project is to fabricate and characterise piezoelectric fibres suitable for ready integration into textile materials. The project considers methods of fiber formation (including the use of additives to enhance the piezoelectric coefficient) and develops novel textile structures (weave, knit, braid, coil) with embedded electrodes. The flexibility and small diameter of the final fiber makes it possible to use them in garment without affecting structure or comfort. Finally, the performance of the fiber generators were evaluated through different applications such as air and water sensor, health and movement monitoring and energy generator...

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Unless otherwise indicated, the views expressed in this thesis are those of the author and do not necessarily represent the views of the University of Wollongong.