Digital Commons Network^™

New Types Of Mckibben Artificial Muscles, Danial Sangian

University of Wollongong Thesis Collection 1954-2016

Actuators are devices that exhibit reversible change in their shape or volume or generate force when externally stimulated. Because of their very similar operation style to biological muscles, actuator materials are also known as artificial muscles. These materials are in demand for many applications, such as medical devices and robotics. These applications normally require an inexpensive actuator system that can offer high force, high strain, and high power density in a relatively short period of time. The device packaging and size of the actuator are also important parameters as currently most of the applications desire very compact and lightweight systems. …

Developing Scanning Electrochemical Microscopy Method For Studying Bio-Corrosion Of Magnesium Alloys And Protective Surface Treatments, Sina S. Jamali

University of Wollongong Thesis Collection 1954-2016

Ways of implementing scanning electrochemical microscope (SECM) for studying corrosion and degradation of Mg in simulated biological solution has been studied in this thesis. SECM was first employed in more conventional mode of operation, namely feedback mode, to provide a baseline for comparison with other imaging modes of SECM. Four modes of SECM were in total exploited including feedback, AC, potentiometric and surface generation/tip collection modes. In feedback and AC modes electro-activity and insulating properties of surface were examined at a local scale. In the AC mode variation in conductivity of solution that was caused by corrosion reactions was also …

Development Of Conducting Polymer Based Wearable Supercapacitors, Chen Zhao

University of Wollongong Thesis Collection 1954-2016

The advent of self-powered functional smart garments has given rise to a demand for wearable energy storage devices since traditional energy storage devices are too bulky, rigid and heavy to be seamlessly integrated into textile structures. Supercapacitors which can be fabricated using non-toxic electrode materials and non-flammable electrolyte have been of interest for smart garments. Smart garments should operate well under mechanical deformation, such as bending, twisting, and even stretching. Wearable supercapacitors are expected to maintain high performance under such conditions.

Carbon based supercapacitors show high power but low specific capacitance due to the non-Faradaic charge storage mechanism. Metal oxides/hydroxides …

3d/4d Printing Tough Hydrogel Composites: A Pathway To Functional Devices, Shannon Edward Bakarich

University of Wollongong Thesis Collection 1954-2016

Hydrogels are a class of hydrated and compliant polymer materials that display a variety of desirable properties for engineering applications including actuation, conductivity, and biocompatibility. Despite their unique range of material properties, the implantation of hydrogels into real world applications has been restricted due to their poor mechanical performance. In recent years a number of toughening mechanisms have been designed to improve the mechanical characteristics of hydrogels. This thesis investigates the use 3D printing as a means to process these ‘tough hydrogels’ into complex structures and functional devices. Two different methods are designed for extrusion printing ionic-covalent entanglement hydrogels. The …

Flexible Graphene Based Materials For Energy Storage, Kewei Shu

University of Wollongong Thesis Collection 1954-2016

With the rapid development of portable electronic devices, increasing interest is being aroused in flexible energy storage units with high energy and power density. The electrodes used in such energy systems should combine superior electrochemical properties with high mechanical flexibility. Graphene based free-standing thin films or papers are promising binder-free flexible electrodes. The main drawback of graphene paper electrode is the deterioration of electrochemical performance caused by the restacking of graphene sheets during the fabrication process. Fabricating 3D structured graphene macro-assemblies can address this issue, but compromise mechanical strength and low areal capacitance.

This thesis considers the development of non-stacked …

Materials And Processes For The Biofabrication Of Peripheral Nerve Guides, Leo Robert Stevens

University of Wollongong Thesis Collection 1954-2016

Injuries sustained to the peripheral nervous system disrupt the body’s major signalling pathway, leading to pain or paralysis. The treatment of serious peripheral nerve injuries currently relies on the use of autografts, whereby secondary nerves are sacrificed to treat the pathology. Recently, scientists and clinicians have sought alternative treatments based on engineered tissue scaffolds that may effectively replace grafted tissues. Several peripheral nerve guides (PNGs) are already available, however patient recovery outcomes using PNGs have thus far been poor compared to autograft treatments. The limited efficacy of current-generation PNGs has been attributed to their failure to replicate the complex structure …

3d Printing Phycotrix™ For Wound Healing, Jeremy Nicolas Dinoro

University of Wollongong Thesis Collection 1954-2016

With the advent of additive manufacturing and its recent use in regenerative medicine, bioprinting has become a promising technology for tissue engineering applications. PhycoTrix™, a sulphated marine-derived polysaccharide, taken from the cell wall of a DNA barcoded green algal spp., (Chlorophyta), has a chemical structure similar to mammalian glycosaminoglycans found within the dermal skin layer extracellular matrix. This sustainable, under-utilised source of biomaterial was developed into a bioink for use in bioprinting. Specifically, a dual-network hydrogel was engineered through ionic and chemical means. This hydrogel was characterised following methacrylation through 1H NMR, FT-IR, and circular dichroism. The physical properties, printability, …

The Development Of Graphene/Biocomposites For Biomedical Applications, Sepidar Sayyar

University of Wollongong Thesis Collection 1954-2016

The development of biomaterials with appropriate properties is a requirement in biomedical research, particularly in tissue engineering. The aim of this thesis was to develop biocompatible, processable biocomposites for biomedical applications using graphene and graphene oxide (GO) as filler.

Graphene, a unique two-dimensional carbon structure with excellent electrical, thermal and mechanical properties has been shown to be an appropriate filler for the development of composites for biomedical applications. Chemically converted graphene (CCG) dispersions were synthesized through reduction of GO, also a suitable filler for developing biocomposites.

Polycaprolactone (PCl), a synthetic biodegradable and biocompatible aliphatic polyester with high processability and low …

Nanostructured Icp-Cnt Electrodes For Capacitive Deionisation And Water Clean Up, Mohammed Suliman Almoiqli

University of Wollongong Thesis Collection 1954-2016

The development of electrodes and flow-through cells in a CDI system are considered in this thesis. Novel 3D nanostructured electrodes and improved designs of flow-through cells in a CDI system are described. The main objectives were: (1) to develop a fundamental knowledge and understanding of reticulated vitreous carbon (RVC), conducting polymers such as Poly(3,4-ethylenedioxythiophene) (PEDOT), single-walled carbon nanotubes (SWCNT) and graphene; (2) to use a RVC electrode structure to build 3D PEDOT microstructure electrodes, 3D nanoweb structure SWCNT and 3D nanoweb hierarchical graphene/SWCNT composite electrodes; (3) to explore possible applications of these electrodes in a CDI system; and (4) to …

Novel Cathode Materials For Bioelectric Batteries, Yang Yang

University of Wollongong Thesis Collection 1954-2016

A bioelectric battery provides a promising alternative to commercial lithium batteries to drive active implantable medical devices (AIMD) due to its ease of miniaturization. Bioelectric batteries use body fluid as electrolyte. The selected electrode materials themselves and the reaction products are both safe for the implantation of these electrodes into the human body. The bioabsordable and high energy density Mg alloy is used as anode. However, most electrocatalysts could not meet the requirements for cathode materials in a bioelectric battery, e.g. possessing electrocatalytic activity as well as biocompatibility. Thus this thesis aims to synthesize novel cathode materials specifically for bioelectric …

Carbon Nanomaterials As Electrodes In Thermogalvanic Cells For Waste Heat Recovery, Mark S. Romano

University of Wollongong Thesis Collection 1954-2016

A possible solution to the worlds growing energy problem is to improve the efficiency of energy conversion processes by harnessing waste heat. Thermogalvanic systems, also known as thermocells, allow the direct conversion of thermal to electrical energy. A device consists of two electrodes operating at different temperatures and placed in contact with a redox-based electrolyte. The temperature dependence of the redox reactions generates a potential difference such that when the thermocell is connected to an external circuit, current and power may be extracted.

The initial part of this work focused on an investigation of K3Fe(CN)6/K4Fe(CN)6 concentration (in aqueous media) as …

Bio-Inks For Drop-On-Demand Cell Printing, Cameron Ferris

University of Wollongong Thesis Collection 1954-2016

A rapidly growing synergy between biological science and engineering technology is currently re-shaping the way we view the challenge of treating injury and disease. In particular, emerging biofabrication techniques that allow the precise construction of complex biological structures have reinvigorated the effort to engineer replacement tissues and organs. In addition to the potential for direct therapeutic approaches, advanced engineered tissues promise to significantly improve in vitro studies of fundamental cell biology and disease processes, and expedite drug development.

Drop-on-demand cell printing technologies are at the forefront of these advances in biofabrication. These approaches offer the ability to place living cells, …

Nanostructured Carbon Electrodes, Dennis Antiohos

University of Wollongong Thesis Collection 1954-2016

Supercapacitors are promising energy storage and power output technologies due to their improved energy density, rapid charge-discharge cycle, high cycle efficiency and long cycle life. Free standing poly(3,4-ethylenedioxythiophene) poly(styrene sulfonate) / single walled nanotube films have been characterised by scanning electron microscopy, Raman spectroscopy and thermo-gravimetric analysis to understand the physical properties of the films. Films with varying compositions of poly(3,4-ethylenedioxythiophene) / poly(styrene sulfonate) and single walled nanotubes were compared by electrochemical impedance spectroscopy, cyclic voltammetry and galvanostatic charge / discharge to understand their electrochemical properties. A comparison of the results shows that having single walled nanotubes dispersed throughout the …

Controlled Drug Delivery From Polypyrrole Powered By Enzymatic Bioelectrodes, Willo Grosse

University of Wollongong Thesis Collection 1954-2016

Galvanically coupling enzymatic bioelectrodes with drug loaded conducting polymers to develop a controlled drug delivery system is investigated. The system is designed to be a novel and sophisticated approach to in vivo drug delivery for the treatment of epilepsy. There is a suite of anti-epileptic drugs (AEDs) that are extremely effective at suppressing seizure activity however; their use is restricted due to debilitating side effects. As such, it is of interest to develop novel drug release methods to deliver the AEDs directly to the target area in the brain and in small doses to minimise, and ideally eliminate, the side …

Fabrication And Characterisation Of Conducting Fibres For Use In Biomedical Applications, Dorna Esrafilzadeh

University of Wollongong Thesis Collection 1954-2016

Fabrication and characterisation of conducting biomaterials in 3-dimensional configuration for biomedical applications have been studied and is presented in this thesis. Different fibre spinning techniques (wet-spinning and electrospinning) were utilised to create multifunctional fibres to be employed for controlled drug delivery and cellular growth supports. Two different classes of organic conductors, namely conducting polymers and graphene, were utilised to induce and develop electrical and electrochemical features in the fibres for their potential applications in drug delivery and cell growth enhancement via electrical stimulation. Physical, mechanical, electrical, electrochemical and biological characterisations of the fibres were investigated.

In chapter two, Poly(3,4-ethylenedioxythiophene) poly(styrene …

Charge Generation And Recombination In Porphyrin Based Dye Sensitized Solar Cells, Matthew James Griffith

University of Wollongong Thesis Collection 1954-2016

This study has investigated the charge generation and recombination behaviour of porphyrin-based dye sensitized solar cells (DSSCs) using a range of time-resolved and steady state techniques. The enhanced understanding of these processes was then utilized to develop unique strategies to circumvent performance limitations associated with injection or recombination, thereby improving the power conversion efficiencies of these devices.

Injection behaviour has been studied using transient absorption with sub-ns time resolution and an optical model employed in conjunction with simple absorption measurements to calculate the absorbed photon-to-current conversion efficiency of devices. Recombination was monitored using stepped-light induced measurements of photocurrent and photovoltage …

The Development Of Electrospun Polymer Nanofibres And Measurement Of Their Individual Mechanical Properties With The Atomic Force Microscope, Adrian Gestos

University of Wollongong Thesis Collection 1954-2016

Electrospun nanofibres are being developed at an ever increasing rate for a range of applications. The intended applications vary widely, from tissue engineering inspired by natural tissue scaffolds, to energy applications as high surface area electrodes in batteries and fuel cell devices. However, the ability to routinely characterise the individual fibres themselves is still catching up with the rate and sophistication of their development.

The characterisation of individual electrospun fibres in regards to their mechanical properties is the main focus of this thesis. Understanding individual nanofibre mechanical properties is important for predicting their suitability in an intended application and can …

Carbon Nanotube Architectures With Metallic Nanoparticles Towards Energy Applications, Peter Sherrell

University of Wollongong Thesis Collection 1954-2016

Within this thesis we demonstrate the formation of 3-dimensional, potentially freestanding, entangled carbon nanotube architectures through the use of previously untested organo-metallic catalysts, Iron (III) Tosylate, Cobalt (II) Tosylate, and Nickel (II) Tosylate. The effect of catalyst concentration, hydrocarbon decomposition temperature and growth time were examined in terms of the produced architectures morphologies. As capacitive devices these as produced carbon nanotube architectures demonstrated impressive maximum capacitances of up to 182.9 F/g with a power density of 15 kW/kg and an energy density of 4.06 Wh/kg.

In addition we develop and optimise the decoration of metallic nanoparticles including, platinum, palladium, gold, …

Fabrication Of Dual Layer Conducting Polymer Electrochromic Devices Using Novel Electrolytes, Satyen S. Desai

University of Wollongong Thesis Collection 1954-2016

Conducting polymers and their application as electrodes in electrochromics has been widely studied because of their high contrast, low power consumption and ease of processability as compared with inorganic metal oxides. Another component of an electrochromic device is the electrolyte. Organic electrolytes are widely used in electrochromic devices but have limitations such as volatility, flammability and leakage. Therefore, one of the aims of this thesis was to develop polymer electrolytes that afford comparable conductivity to organic electrolytes without the drawbacks mentioned above. The following polymer electrolytes containing polyethylene oxide (PEO), with molecular weight (2,000, 10,000 and 20,000), salt lithium perchlorate …

Wet-Spinning Of Nanostructured Fibres, Rouhollah Jalili

University of Wollongong Thesis Collection 1954-2016

The development of nanostructured fibres from organic conductors produced via wet-spinning technique is described in this thesis. The main objectives are (1) to develop the fundamental knowledge and understanding of organic conductors such as conducting polymers, single walled carbon nanotubes (SWNTs) and graphene, (2) to create multifunctional nanostructured fibres based on PEDOT:PSS/SWNTs and liquid crystals of graphene oxide (LC GO), (3) to study the effects of spinning formulation on the electrical conductivity, electrochemical performance and mechanical properties of the nanostructured fibres and (4) possible applications of these structures in fibre based energy storage systems.

A novel continuous wet-spinning approach was …

Chemically Converted Graphene Dispersions And Graphene Films, Marc Benjamin Müller

University of Wollongong Thesis Collection 1954-2016

The formation of graphene dispersions and its subsequent characterisation form the basis of this thesis. A range of experimental techniques were employed for this characterisation, namely atomic force microscopy (AFM), contact angle and conductivity measurements, UV-visible spectroscopy, Fourier transform infrared spectroscopy (FT-IR), elemental analysis, pH-zetapotential, acid-base titration, and capillary zone electrophoresis (CZE). Various fabrication techniques such as layer-by-layer self-assembly and vacuum filtration were used to create thin transparent, conducting films as well as micron thick conducting paper.

Graphene dispersions were created by oxidising graphite, exfoliating graphite oxide to graphene oxide (GO) via sonication, and reducing it to chemically converted graphene …

Nanostructured Organic Solar Cells, Dillip Kumar Panda

University of Wollongong Thesis Collection 1954-2016

A wide range of state-of-the art solid-state dye-sensitized solar cells (ssDSCs) have been fabricated employing in situ photo-electrochemical polymerization (PEP). The ssDSCs were fabricated using nano-crystalline TiO₂ as an electron acceptor, high molar extinction coefficient ruthenium-complex dyes with wide UV-Vis absorption range as photo-sensitizer, poly(3,4-ethylenedioxythiophene) (PEDOT) as hole transporting material (HTM), and both metallic and non-metallic counter electrodes. Potential problems with PEP are un-optimised filling and poor distribution of the conjugated polymer inside the pores of the nano-structured electrode. Better pore filling and hence better photovoltaic performance has been achieved here by optimising the polymerization conditions such as illumination …

Novel Graphene Composite Materials, Widsanusan Chartarrayawadee

University of Wollongong Thesis Collection 1954-2016

Graphene is another form of carbon material which has many outstanding properties such as large surface area, high Young’s modulus, high charge carrier mobility, good thermal conductivity and excellent transmittance properties. Graphene can be synthesized by different methods and can be readily prepared in both solid powder and colloidal aqueous dispersion. Furthermore, graphene as a carbon material has potential to form composites with other materials such as metal nanoparticles, conducting polymer and other forms of carbon material such as carbon nanotubes. As part of this research, graphene was prepared from graphene oxide as a colloidal aqueous dispersion; keeping in mind …

Analysis Of High Performance Polypyrrole Actuators, Wen Zheng

University of Wollongong Thesis Collection 1954-2016

Electrochemical actuators based on polypyrrole (PPy) have been constructed and characterized. The actuation performance was analyzed in terms of several main parameters: thickness, scan rate, applied stress, cycle life and creep. Two different dopants and two different forms (tubes and free standing films) were produced to investigate their effects on the actuation performance and the underlying mechanisms of actuation.

The actuation strain generated by the PPy materials when an external load was applied was found to be the sum of three individual time-dependent processes: strain generated directly from charge and solvent injection; strain generated from elastic modulus changes; and strain …

Nanostructured Catalytic Electrodes For Fuel Cells, Weimin Zhang

University of Wollongong Thesis Collection 1954-2016

The main goal of this study was to design and develop novel electrocatalysts that exhibit high catalytic activity whilst maintaining 100 % selectivity for a desired product. Such catalytic materials will improve the performance of fuel cells by increasing cell efficiency and by removing by-products, thus eliminating waste in fuel cells electrocatalytic reactions.

A cobalt porphyrin electrocatalyst embedded in a conducting polypyrrole matrix was prepared using either a vapour phase polymerization or in-situ chemical polymerization method. The composite material showed enhanced catalytic activity and stability toward the electrochemical reduction of oxygen when compared with the original cobalt complex. The performance …

The Controlled Release Of Dexamethasone From Polyterthiophene-Based Conducting Polymers, Grace Stevenson

University of Wollongong Thesis Collection 1954-2016

Controlled drug delivery has been widely researched since being introduced over 50 years ago. Systems for controlled release are important for improving the pharmacological profile of therapeutic compounds. Controlled delivery systems have been designed to give sustained and delayed release as well as for targeted delivery which minimises side effects such as toxicity, which can be associated with systemic drug delivery. Many materials have been used for controlled release, with the main focus being on polymer based systems.

Over recent years conducting polymers have been used in controlled drug release applications. These materials possess unique redox switching properties which enable …

Using Band Microelectrode Arrays To Investigate The Cut Edge And Bare Corrosion Behaviour Of 55% Al-Zn Coated Steel, Troy Lowe

University of Wollongong Thesis Collection 1954-2016

This thesis describes investigations into the initiation and short term atmospheric corrosion behaviour of 55% Al-Zn metal coating. It explores the influence of ions produced by localised oxidation and reduction reactions to affect nearby sites during bare and cut edge corrosion. Band microelectrode(BME) arrays were used to achieve this aim.

Al-40% Zn alloy exhibiting solid solution precipitate microstructures were prepared as model alloys for the α-phase of a 55% Al-Zn metal coating on steel. The effect of electrolyte composition and pH on the polarisation electrochemistry was investigated. Enhanced anodic processes were observed in Cl- compared to SO4 2- electrolytes. The …

Conducting Composite Fibres, Alberto Javier Granero Rodriguez

University of Wollongong Thesis Collection 1954-2016

The production of conducting composite fibres via wet-spinning is studied in this thesis. The main objectives pursued are (1) to develop the knowledge and understanding of such materials, (2) to create new composites based on biopolymers or synthetic polymers and conducting materials such as carbon nanotubes (CNTs) or conducting polymers (CPs) for possible use in medical and bionic applications and (3) study the effects of pre- and post- processing parameters on the electrical and mechanical characteristics of the composite fibres.

Two wet-processing techniques are used to produce composite fibres, i.e. polyelectrolyte complexation and solvent / non-solvent wet spinning. These methodologies …

Carbon Nanotube Composite Architectures For Use As A Novel Electrodes, Suriya Ounnunkad

University of Wollongong Thesis Collection 1954-2016

Electrode platforms based on carbon nanotubes (CNTs) or their composites have been extensively investigated over the last two decades since their discovery. CNT‐based electrode platforms have been intensively researched in the electroanalytical and electronic fields. CNTs offer many excellent properties to create electrochemical devices and also improve the properties of composites made from them. Consequently, the theme of this thesis utilises one kind of CNT architecture, which to date has not been successfully investigated for use in electrochemical sensing applications. This architecture, CNT paper or CNT Buckypaper (BP), can be easily prepared and processable by a vacuum‐assisted filtration of well‐dispersed …

Printing Conducting Polymer Structures On And Embedded In Biopolymer Platforms, Charles A. Mire

University of Wollongong Thesis Collection 1954-2016

Tissue engineering (using laboratory grown tissue to treat injury) and bionics (technologically augmenting the human body) are advancing the range of medical treatments and prostheses options for patients. New materials continue to be developed which address important tissue engineering and bionics requirements, such as improved cellular response, tissue-like softness and exibility, and bio-degradation where appropriate. These materials include biopolymers, such as chitosan and hyaluronic acid, and conducting polymers, such as polyaniline and poly(3,4 ethylenedioxythiophene)/poly(styrenesulfonate) (PEDOT/PSS). In tandem with new material development, fabrication methods are needed to construct tissue scaffolds or bionic devices. Where conventional fabrication methods do not work, new …