PhD in Materials

Research areas

Biomedical Materials and Engineering

The complementary disciplines of materials science and engineering can provide understanding of complex, hierarchical systems in biology. The specific strategy of the group is to produce solutions to clinically relevant problems, through the study of normal and disordered tissue structure/function. An integrated multiscale approach is taken with respect to both structural organization and reactivity of tissues studied from the nano- to the macro-scale. Examples include the modification of the stem cell niche, using both biomaterial and engineering cues, to explore their potential to differentiate into specific cell lineages for use in regenerative medicine. Specific areas of interest are the musculoskeletal, vascular and neuronal systems, aimed at a greater holistic understanding of the mechano-biological and electrophysiological tissue behaviour. Underpinning this strategy is an effort to advance experimental techniques, both within the School, across Queen Mary and through use of UK central facilities. As an example live cell imaging is employed in conjunction with confocal imaging to establish quantifiable parameters to explain mechanotransduction signalling pathways. Extending out from direct tissue analysis is the study of micro- and macro-scale fluid flows, which influence both the tissue environment and cellular functions, as well as contributing to the long term structural outcomes of medical significance, viz prognosis in vascular aneurisms. The Group is also involved in advancing new diagnostic tools and techniques, which range from spectroscopic analysis of cancer tissue in vitro, in vivo sensors to microcapsules for the delivery of biological agents. The experimental approach is supported by a considerable utilisation of in silico modelling designed to predict early damage or disease, thereby developing the potential for regenerative medicine strategies. Ultimately, a progression to direct medical application is anticipated. Future biomaterial developments include smart bioactive nanocomposite coatings for enhanced hip prostheses, novel bioceramics for hard tissue repair and bone tissue engineering, which can be evaluated with both laboratory-based tests and animal models. Such new generation materials can be developed by Queen Mary-associated companies such as Progentix Orthobiology and Apatech, the latter having recently been acquired by Baxter International.

Energy Systems

Energy use and the resultant environmental and climate effects are the biggest issues (along with their driver, population growth) we will face in the Twenty-First Century. This has brought the energy area at the forefront of public and political awareness. Energy is also a very wide area, encompassing many engineering and scientific disciplines. It is therefore important to strategically target energy research activities in order to be effective. At Queen Mary we have a long tradition and established areas of international research reputation and excellence in key aspects of the energy theme (heat transfer, combustion and fuels, alternative and sustainable fuel use and generation, novel powerplants, materials for solar cells, sustainability and wind turbines). Stemming from these areas we intend to continue being world leaders in targeted research activities in the broader energy theme.

Currently about 15 per cent of total energy demand is for long-distance transportation (requiring powerplants of power density that cannot be effectively met with renewable sources); and the remaining 85 per cent is for electricity generation, industrial and agricultural processes, heating and cooling (which can be met with lower-power-density powerplants with energy provided from renewable and sustainable sources). Therefore our strategic vision is governed by concerns of renewable and sustainable energy sources, while ensuring we also meet long-distance transportation needs despite the sustainability threat of fossil-fuel reserves. On the 85 per cent of the demand we need to secure future energy supply by the appropriate mix of renewable and sustainable sources of energy; and on the 15 per cent of the demand we need to minimize the effects of use of fossil fuels, and use the renewable sources to generate surrogate power-dense long-distance-travel liquid-fuels for the future. These needs of humanity fit very well with our established areas of research excellence. Our strategic vision in energy points to applications of engineering and scientific disciplines in wind turbines, solar and geothermal energy, generation and use of alternative future fuels, and novel powerplants and thermodynamic cycles.

Research in heat transfer is pertinent to all forms of energy conversion and use. Established directions of heat transfer research continue, and have expanded in the areas of nanofluids, and interaction with materials for solar panels. Research in aerodynamics, turbomachines and novel powerplants is ongoing, and we are expanding into wind turbine applications and combined solar powerplants, with planned future interactions on blade materials and distributed power control. Research on engine-fuel performance and emissions with alternative and sustainable fuels continues, and we have recently expanded in the areas of alternative and surrogate fuel generation (biofuels, hydrogen from artificial photosynthesis, and surrogate fuels). Emissions predictions with novel computational techniques is an ongoing theme. Interactions on theoretical, numerical and experimental techniques within the School in the other research themes, across Queen Mary, within the UK and internationally are established and are being expanded.

Research in sustainability is funded through a number of collaborative and industrial research programmes and embraces areas such as environmentally friendly processing, renewable materials, life-cycle engineering and waste remediation. There are significant activities in recycling of polymers and rubbers and clean processing methods using supercritical CO2 fluids. The group has a strong international reputation in ‘green’ composites that are biobased, compostable or recyclable. Fully biobased and biodegradable composite materials are being developed based on bioplastics in combination with natural fibres such as flax, hemp or nano-sized cellulose whiskers. Particularly noteworthy is the groups work on fully recyclable self-reinforced polypropylene (SR-PP) or 'all-polypropylene' composites that has been a major innovation in the area of engineering plastics and is now commercialised under the name PURE® by Pure-Composites in The Netherlands and its license Tegris® by Milliken in the US. Work on all-polymer composites has recently been extended to a variety of other polymer systems including polyethylene (PE) and polyethylene terephthalate (PET), aramid and cellulose.

Modelling of Fluid and Solid Systems

In recent years, computational modelling and simulation has become one of the leading fields in Engineering. In some industries, eg automotive, mechanical or aerospace, a paradigmatic shift from development based on physical prototyping to that driven by computational approaches has been realised due to the increase of computational power (software/hardware) and due to improved and new numerical methods. This still ongoing process is strongly driven by academic research often in close collaboration with industrial software developers. In the area of solid mechanics it is dominated by Finite Element Methods (FEM) but it became clear that these approaches need to be accomplished by other methods – eg Discrete Finite Element Method (DFM), Boundary Element Method (BEM), Meshless Methods – to cover the full range of applications. For fluid problems, computational fluid dynamics (CFD) is well established with research now focussing on specialised and more advanced fields like LES (Large Eddy Simulation) and DNS (Direct Numerical Simulation). Using all these methods a second more goal-directed group of methods is developed, which enables to identify optimal and robust designs. Here deterministic and stochastic methods are used and still further developed (particle swarm methods etc). This is in particular of interest for approaches where the gradient information for sensitivities and optimisation are obtained by adjoint methods and automatic differentiation. Challenges can be found in topology optimisation addressing highly nonlinear problems (crash, turbulent fluids), in shape optimisation studying complex structures (complete car bodies for crash, aerodynamics, etc) and in combination with robust design and reliability. Several of these optimisation tools are then employed for control techniques.

In addition to research on methodological improvements and developments, the investigations also enable new approaches in a large range of applications. Some of the currently most interesting fields can be found in disciplines such as Bio-fluids, Nanomaterials, Nanomechanics, Nano and Multi-scale Simulations, Material Modelling, Dynamics and Control, Discrete Population Modelling, Highly Non-linear Mechanics (Crashworthiness, Turbulence), Acoustics and coupled problems (Thermoelasticity, Aeroelasticity, Fluid-Structure-Interaction etc).

The vision of the group "Modelling of Fluid and Solid Systems" of the School of Engineering and Materials Science is two-fold: first to stay among world leaders in some specialised areas of development of numerical methods (eg DFM, BEM, Meshless Methods, LES-DNS) and second to establish and extend our advanced applications (eg Biomechanics, Nanotechnology, Energy Systems and Automotive Optimisation) ideally in collaboration with the other research groups of the School of Engineering and Materials Science, Queen Mary and a worldwide network of collaborators.

Nanostructured Materials

The development and understanding of nanostructurised materials is currently a major research theme at Queen Mary. These nanomaterials have a range of unique physical and chemical characteristics, and have the potential to be used in a multitude of novel applications from new functional materials and sensors and actuators, materials for energy conversion and storage to biomaterials. It is because of this diversity that the work of this group overlaps with other research groupings within Queen Mary.

A large area of research within the Nanostructured Materials group is in nanocomposites. A major research effort is around the creation of multi-functional polymeric materials based on carbon nanofillers such as carbon nanotubes, graphene and carbon black. Research in carbon nanostructures ranges from synthesis and electrical properties to applications and is studied in collaboration with the Physics Department. A specific area of interest is higher-order fullerenes filled with guest atoms and electronic properties of nanotubes. Extensive research activity involves the application of carbon nanotubes in polymer composites for the creation of multi-functional materials with interesting mechanical, electrical, thermal and optical properties. Specific areas of research are the creation of high strength polymer fibres, sensory fibres for smart textiles, smart rubber, improved flame retardancy of polymers, transparent conductive films and new hierarchical carbon fibre/carbon nanotube composites with localized damage sensing capability. Besides carbon nanoparticles a significant research activity is in the area of electrospun polymer nanofibres, cellulose nanofibres and nanoclays. Cellulose nanofibres such as cellulose whiskers and nanocellulose produced by bacteria are used to create fully biobased nanostructured materials with interesting mechanical and optical properties. Nanospider® technology is used for the creation of electrospun nanofibreous materials for a wide variety of applications such as filtration, textiles, medical and composites.

There is currently also a great interest in size effects in ceramic materials as many properties change dramatically when the grain size or component dimensions are below 100 nm. For the production of these materials the Queen Mary team has unique Spark Plasma Sintering (SPS) facilities that allow densification of nanoceramic powders to be achieved with minimal grain growth. Research is focused on the effect of grain size on the mechanical properties of metals and structural nanoceramics and the electrical properties of ferroelectric, varistors and thermoelectric nanoceramics. Applications of these ferroelectrics are in non-volatile memories, and actuators and sensors in microelectromechanical systems (MEMS). The increasing demand for size reduction in the microelectronics industry is approaching the nanometre scale, where our experimental and theoretical work is showing that the properties of these functional ceramics strongly diverge. Our work on nanoscale metals and structural ceramics involves development of improved tungsten components for fusion reactors and anti-ballistic protection with industrial collaborators, respectively. Next to the creation of nanostructured ceramics the group is also involved in the development of conductive ceramic nanocomposites using carbon nanotubes or graphene as a conductive filler. We have shown that rapid sintering by SPS can preserve the structure of such carbon nanostructures, opening up the possibility to create multi-functional ceramic materials with improved mechanical, electrical and thermal properties.

A very distinctive area of research that has recently been introduced to Queen Mary is that of micro- and nano-encapsulation. This work is based on a layer-by-layer (LbL) adsorption approach utilising oppositely charged polyelectrolytes on colloidal template particles, including emulsions and gas bubbles. A great variety of materials can be encased in capsules with controlled delivery and release properties, sensing, magnetic navigation, light addressing and more functions to meet scientific and industrial interest. Our work on stimuli-responsive nanoparticles and nanocapsules has attracted great interest because of the broad opportunities for in vivo medical applications. Hollow LbL capsules can be refilled with various molecules for drug delivery. Drug release can be activated on demand by local changes in pH or by remote physical stimuli.

Imaging is a strength of both the School and the College with a number of centres of excellence in institutes on all campuses. Within the School, nanoscale imaging is exemplified by the NanoVision Centre that was developed to provide a facility to support nanomaterials research and to develop new imaging platforms. However, research extends beyond these bounds to the use of national and international facilities (eg synchrotron X-ray experiments). For routine characterisation of nanostructures the NanoVision Centre is well-equipped in scanning probe techniques and scanning electron microscopy, while having basic facilities in transmission electron microscopy. In this area of research developments in advanced nano-imaging techniques there is a strong emphasis on integration of imaging and nanomechanics, where structure-property relations at the molecular scale are a key theme. There is also considerable overlap with the biomaterials group, since many of the systems studied are biological materials. The development of new techniques has been, to date, associated with 3D imaging of biological tissue and with the integration of different technologies to produce new approaches to imaging and nanomechanics. These developments have been built around mutual partnerships with instrument suppliers, in producing both novel techniques and high profile research publications.

A key element supporting nanostructured materials research is having available the necessary multi-disciplinary approaches to manufacture and, as required, functionalize surfaces at the nano and micro-scales. This is achieved by having staff with chemistry, physics, materials science and engineering backgrounds. The group has the technological capability to pattern surfaces with nanostructure via a variety of routes. These routes include chemical synthesis, photo-embossing, EHD direct writing, solid free forming fabrication of meta materials and tissue engineering scaffold structures and 3D inkjet printing of ceramic and polymeric materials. These techniques continue to be developed to provide enhanced group capability to investigate novel material structures and cost effective manufacture of advanced materials. Genuine disruptive technology skill base includes dry powder dispensing at ten times speed of competitive technology and EHD deposition with feature resolution one-tenth that of conventional inkjet.

Nanoforce: Application of the team’s research is significantly enhanced by the creation of Nanoforce Technology Ltd, a wholly-owned Queen Mary subsidiary devoted to nanomaterials research for exploitation by industry. Nanoforce provides access to a broad range of unique world-class processing facilities, such as spark-plasma sintering for development of nanoceramics and dedicated equipment for production of polymer nanocomposites.