Interface Analysis Centre: Current Research
The Interface Analysis Centre is a fully equipped technical centre specialising in surface and materials analysis. Operating successfully since 1990, the IAC has a multi-million pound range of analytical instruments at its disposal, maintained by highly skilled and dedicated technical staff. Specific problems are dealt with by academics also pursuing cutting-edge research. Most researchers have several years of industrial experience and are knowledgeable in the theoretical and experimental aspects of materials science often acting as consultants to various industries both home and abroad.
1 Solving a Massive Problem with a Minuscule Solution (Dr T Scott)
Clean water is critical for sustaining human life. But the provision of clean water is increasingly difficult due to pollution, industrialisation and population growth, particularly in the developing world. However, there is a tiny solution to this enormous problem: nanotechnology. Engineered nanomaterials such as those being developed at the IAC could be the key that unlocks a generation of cheaper, faster and better water treatments. Environmentally-compatible nanoscale materials such as nanotubes or nanoparticles prove highly effective at cleaning up polluted groundwater. Introducing these minuscule, water-suspended cleaning agents – far smaller than bacteria at less then 100nm in size – into polluted aquifers can destroy or immobilise a wide range of toxic pollutants.
Recent ground-breaking work and complementary materials analysis at the IAC has demonstrated how vacuum heat treatments improve the environmental longevity and reactivity of metallic iron nanoparticles for water treatment. While these iron nanoparticles have yet to be deployed in the UK or the developing world, the IAC, in collaboration with the new Nanoscience and Quantum Information (NSQI) centre, aims to spearhead further development of this technology and play an active role in UK commercialisation.
2 Micro-Crystals, Macro-Solutions (Professor G Allen)
Global cement manufacture accounts for five percent of all the carbon dioxide generated worldwide. Using lime as a replacement for cement significantly reduces this CO2 due to its lower kilning temperature, which also makes lime an ideal low tech material for the developing world. The process by which lime sets hard involves a carbonation reaction through which atmospheric CO2 is absorbed and fixed into limestone, and this “carbon storage” further enhancing lime's environmental credentials. However, in conventional cements and concretes other factors such as porosity, humidity and liquid water creep in to limit the rate of reaction and stop the CO2 getting to where it needs to be - fixed in limestone.
In order to maximise the rate of carbonation, the reaction needs to be understood, and the best location to study it is on the lime crystals themselves by investigating the interfacial reaction at a microstructural level. IAC researchers, using high magnifications, can see the CO2 “in real time” as it is converted into limestone in situ. When these surface reactions are understood, then the optimum conditions for carbonation will be within reach. All that remains it to tailor the porosity to get the reactants in the right place, but as this porosity is direct proportion to particle size, it can be controlled! By maximising the rate of this reaction, lime can be engineered to set harder and faster, creating a structural material that literally soaks up CO2.
Figure 1– Single lime crystals growing on a sand grain.
3 Spectroscopy Where the Sun Don’t Shine (Dr J Day)
In 1928, Indian physicist Chandrasekhara Raman won a Nobel prize for his discovery that light can undergo a weak but perceptible colour change when scattered by matter. The resulting Raman spectrum is characteristic of the chemical bonds involved and can distinguish between such diverse substances as diamond and graphite or cancerous and healthy tissue.
The IAC is involved in several projects to make miniature Raman probes for industrial and medical applications that cannot be analysed in any other way. For example, cancer of the oesophagus, the fastest growing incidence of any cancer in the Western world and frequently associated with chronic heartburn, which may change the structure of the oesophageal wall. The subtle differences in the Raman spectra of cancerous and healthy tissue mean that an early, automated diagnosis of oesophageal cancer is a real possibility.
However, the proportion of light that undergoes Raman scattering is as low as one part in a billion, and the optical equipment needed to collect the light may generate Raman signatures much stronger than those of the cancer. It is therefore vital to design miniature probes with multiple filters and lenses as close as possible to the point of analysis to primarily measure only the tissue's signal. Since fibre optics have dimensions similar to those of human hair the precision required is far greater than that normally achieved by conventional engineering.
In collaboration with Gloucester Royal Hospital (GRH), Renishaw and KeyMed Olympus, the IAC uses semiconductor fabrication facilities within the Department of Electrical and Electronic Engineering to make probes small enough to fit inside medical endoscopes. Work at GRH has demonstrated that the spectra produced in just 2 seconds can detect cancerous tissue with an accuracy similar to that of trained pathologists looking at biopsies in the laboratory. Work is continuing to make the probe suitable for in-vivo studies so that live trials can begin.
Raman Probe incorporated into medical endoscope