Does size really matter? Adventures in nanospace
Palladium nanoparticles decorating the edges of the E. coli used to synthesis them. (Lynne Macaskie and Kevin Deplanche, Unit of Functional Biomaterials, School of Biosciences, The University of Birmingham).
Nanoscience is the science of the very small from one thousandth of a metre down to one billionth of a metre, one nanometre. Researchers at Cardiff University build particles right at the small end of this scale to explore how this affects their reactivity.
'Research at this scale has shown that size really does count,' explains Michael Bowker, Professor of Chemistry at Cardiff. 'Gold is of course gold in colour, but nanoscale gold particles can be blue or red depending on their exact size.' The electronic structure of a material changes as the particle size changes. This not only has implications for colour but also for reactivity.
At such very small scales nanoparticles are dominated by their surfaces and it is the way that reactions take place at these surfaces that is the focus of research at Cardiff. ' Nanoscale particles of platinum are used in the catalytic converters of cars to remove pollutants. Future applications may include the use of silver nanoparticles as surface coatings in operating theatres to make them resistant to bacteria such as MRSA,' suggests Bowker.
Bowker's team are currently working on 'ordered arrays' of nanoparticles, surfaces coated with particles of exactly the same size. Such arrays will allow accurate measurement of the variation of reactivity with particle size.