SREP Projects for 2016–2017
1. Thin Film Technologies for the Reduction of Coral Bleaching on the Great Barrier Reef
Supervisors: Dr Joel Scofield, Dr Emma Prime, Prof Greg Qiao
Increasing water temperatures combined with high light intensities is leading to significant coral bleaching. These conditions affect the delicate symbiotic relationship between the coral and zooxanthellae, which give colour and life to the coral. Sustained exposure to these conditions lead to bleaching, an effect that is threatening the future of the Great Barrier Reef. One approach to mitigate this effect is to reduce the light intensity that the coral and its micro-organisms experience. Several approaches to achieve this have been identified and rely on the formation of a well-spread thin-film on the water surface.
This project will involve the optimisation of monolayer formulations, which incorporate light scattering or absorbing components in preparation for small scale field trials, which will start in January 2017 in Townsville, Queensland. These field trials will be conducted on tanks containing coral samples to test the effectiveness of the technology on reducing coral bleaching. Monolayers are ideal for this application due to their self-spreading and biodegradable properties while only requiring very small amounts to form. However, additional work is required to test and optimise these systems. The performance of these films will be analysed in the lab by measuring surface pressures, self-spreading properties, the lifetime of these films and their effect on light attenuation. This project is an opportunity to gain experience working on industrially relevant research and obtain skills in simple materials chemistry and characterisation techniques.
2. Thermochromic Technology for the Packaging Industry
Supervisors: Dr Paul Gurr, Prof Greg Qiao
As part of the Industrial Transformation Research Hub, “Unlocking the Food Chain”, between UniMelb and Mondelēz, the Polymer Science Group is aiming to develop innovative packaging for the food industry to expand export markets primarily into Asia. One target of this SREP research project is to develop thermochromic polymer systems (colour-changing labels) for the use in the food industry. A famous example is the American Coor’s Light beer labelling, which changes colour upon cooling to show optimal drinking temperature.
Our novel thermochromic system will change colour upon cooling either reversibly or irreversibly, depending on the chemistry. Current technologies predominantly use Leuco dye systems, which utilise non-food-grade dyes, toxic crosslinkers and the use of undesirable formaldehydes, and phenolics which inhibit their use to solid substrates such as glass, metal or thick plastic barriers. In this project we aim to develop thermochromic systems utilising emulsion polymerisation and food-grade components. The successful SREP student will develop and thermochromic system which satisfies the requirement for food-safe thermochromic labels. The student will learn the techniques of emulsion polymerisation, polymer synthesis, isolation and identification of polymers and components using analytical instruments including GPC, NMR, UV-Vis and MALDI-ToF.
3. Product Engineering and Formulation in Personal Care Products: Screening Surfactant and Polymer Systems
Supervisors: Alisa Bai, Prof Raymond Dagastine
Polymer-surfactant (PS) complexes are ubiquitous in personal care products where understanding their microstructure and function in a complex fluid (e.g., shampoo, conditioner, laundry detergent, processed foods, pharmaceutical formulations etc.) is critical for controlling or improving product formulations. Our group has a ten-year history collaborating with personal care product companies through studying the fundamental science of PS complexes in order to provide an enabling understanding in future formulations. This project will focus on screening a series of surfactants and polymers for their potential use in shampoo formulations. This will include using surface tension to probe when these molecules aggregate in solution, as well as examine phase separation behaviour of the polymer surfactant mixtures. This project will provide opportunities to interact regularly with our industry partner in progress meetings and gain a perspective of how interfacial phenomena and soft matter engineering play a role in industrial formulation problems.
4. Coordination-Based Antibacterial Nano-Coatings
Supervisors: Dr Nadja Bertleff-Zieschang, Md. Arifur Rahim, Prof Frank Caruso
Colonisation of pathogenic bacteria and fungi on medical implants and surgical devices presents a serious risk for complications in hospital care and the prevention of biofilm formation remains a major health issue. Current antimicrobial coatings can be divided into anti-adhesive, contact-killing, and release-killing materials. The latter includes silver (Ag) ions and Ag nanoparticles embedded polymeric materials. Note that Ag has been known for their bactericidal properties for centuries. However, the preparation of such Ag-embedded coatings requires multiple steps and these coatings are generally expensive.
Natural phenolic compounds, low cost and abundant in plant kingdom, have been historically known for their antibacterial activity (e.g., wound healing). However, utilising these natural compounds in the form of thin and ultra-thin films towards antibacterial applications has largely been unexplored. Recently, our group developed a versatile surface nano-coating technique based on the coordination chemistry of phenolic compounds and transition metals (Ejima et al., Science, 2013). It is expected that such coating systems might have tremendous potential for antibacterial applications due to the synergistic effect of their hybrid (organic-inorganic) hierarchical structures. Within this research project, the student will acquire hands-on experience in the preparation, characterisation, and antibacterial evaluation of these coordination-based nano-coatings.
5. Multifunctional Hybrid Drug Delivery Systems
Supervisors: Dr Nadja Bertleff-Zieschang, Md. Arifur Rahim, Prof Frank Caruso
Targeted drug delivery systems have emerged as a promising alternative to current therapies based on molecular drugs, e.g., delivery of a high drug payload, accumulation of the drug at the disease site, stimuli-responsive drug release, and incorporation of other functionalities such as diagnostic tracers. However, combining all these benefits in contemporary delivery systems requires sophisticated and chemically demanding preparation. Hence, a facile, one-step strategy to design multifunctional delivery systems is highly desirable.
Our group has long-standing expertise in the synthesis of one such drug delivery system known as hollow capsules. In addition to polymeric counterparts (capsules), we recently introduced a hybrid capsule system exploiting metal-phenolic interactions (Ejima et al., Science, 2013) that can be prepared within a minute via a simple one-step protocol. Such hybrid systems have shown potential in therapeutic delivery and bioimaging applications. The aim of this research project is to integrate multiple functions to such systems for biomedical applications. In particular, the student can expect to acquire experience in the preparation and characterisation of multifunctional capsules for drug delivery and learn how to investigate their biomolecular interactions in cell studies.
6. Impossible Janus Droplets: Making Droplets Using Two Immiscible Oils via Microfluidics That Defy Thermodynamics
Supervisors: Emily Jamieson, Prof Raymond Dagastine
Complex particles, such as compound or multiphase drops, have gained considerable interest due to their wide industrial application in areas such as pharmaceuticals, drug delivery, cosmetics and food sciences. In particular, there has been keen focus on the generation and study of Janus drops due to their potentially advantageous anisotropic properties. Bringing two immiscible fluids into contact within a third mutually immiscible fluid creates a Janus drop. Traditionally this has been accomplished by agitation; however, recent advances in the fabrication of microfluidic devices have allowed greater control and precision in the formation of monodisperse particles, making it a recently favourable technique for the preparation of Janus drops and emulsions. Existing thermodynamic models dictate when Janus drop formation is possible based on the interfacial tensions of the fluids involved. Our group has developed novel approaches to make Janus droplets in what are defined as thermodynamically impossible systems. This project will screen a number of potential surfactants using surface tension measurements to identify the appropriate conditions to form Janus droplets in a microfluidic device. The student will then have the opportunity to work with a PhD student in making and characterising Janus drops with microfluidic devices and video microscopy.
7. Atmospheric Oxidation Chemistry of Amines (2 or more students)
Supervisors: Dr Gabriel De Silva
Amines contribute to air pollution when released into the atmosphere from industrial sources, farming, and biomass burning. There is particular concern over the formation of toxic pollutants from the oxidation of volatile amines used as solvents in carbon capture and storage. This project is computational in nature, and will use quantum chemical methods to model the chemical reaction pathways involved in the atmospheric destruction of amines. The results of this project will be used to improve current air pollution models to account for this emerging class of pollutant.
8. Bioinspired RAFT Polymerisation
Supervisors: Dr Qiang Fu, Dr Thomas McKenzie, Ke Xie, Prof Greg Qiao
Inspired by the energy transfer reactions of biological cells, we aim to develop an improved reversible addition−fragmentation chain transfer (RAFT) polymerisation system. A designed metal–organic framework (MOF) nanoparticle will be implanted in this system to mimic the biological cell-induced redox process. This will allow for continuous generation of initiating radicals, inducing the RAFT polymerisation of various monomers in the presence of thiocarbonylthio compounds. The described system is expected to show advances including faster reaction speeds, facile purification process and good controllability compared with current RAFT polymerisation techniques. Novel polymers and nanoparticles will be prepared via the bioinspired polymerisation technique.
9. Sunlight-Driven Film Formation for Nanoscale Patterning
Supervisors: Tom McKenzie, Dr Shereen Tan, Dr Qiang Fu, Prof Greg Qiao
Polymerisation driven by light is a rapidly expanding area of scientific research. Our group has recently discovered a method for making polymers with highly controlled structures (size, shape etc.) using visible light (a cheap commercial blue LED strip light) as the source of activation. In the proposed project, this newly developed method will be applied to the surface of a solid substrate to grow thin polymer films. Exploitation of the spatiotemporal nature of light will be explored for creating various patterns and gradients. The use of solar irradiation is highly attractive for the commercial translation of such technologies, and so the use of sunlight to directly drive film growth and formation will be assessed. Hopefully we will get some nice weather over summer!
10. Development of Novel Electromembrane Processes
Supervisors: Dr George Chen, Prof Sandra Kentish
Electromembrane processes are based on ion migration across ion exchange membranes from one solution to another under the influence of a potential gradient. Electrodialysis, one of these processes, has been widely explored for water desalination, wastewater treatment, energy storage, and food and beverage processing. Some of the applications require the membranes to be selective to monovalent ions. For example, demineralising dairy streams (i.e., milk or whey) using electrodialysis can separate the undesirable constituents (i.e., sodium and potassium) from the nutritionally beneficial divalent ions, such as calcium, magnesium and zinc.
While monovalent selective ion exchange membranes can be used in this process, commercial applications of these membranes are hindered by the limited monovalent/divalent selectivity, high electrical resistance and high manufacturing costs. Nanofiltration membranes can offer superior monovalent ion selectivity, but are subject to severe membrane fouling as nanofiltration is a pressure-driven process. This significantly lowers separation efficiency and increases energy consumption. On the other hand, electrodialysis technologies are much less susceptible to membrane fouling because these processes are not pressure driven. This project will investigate the use of nanofiltration membranes with ion exchange membranes to fractionate monovalent and divalent salts in an electrodialysis system, combining the advantages of the electrodialysis and nanofiltration technologies. The voltage-current density characteristics, as well as the separation performance of monovalent and divalent salts, will be examined.