Molecular Dynamics and Reactivity in Complex and Confined Fluids

Of the three states of matter liquids are the most difficult to deal with. The molecules interact with one another all the time (unlike in gases) and yet possess no long range order, and move about all the time (unlike in solids). In the past this has made them hard for scientists to study. As a result much early quantitative research focussed on the gas phase, which is a problem for chemistry and biology, where most important processes actually happen in liquids. Fortunately our understanding of some common liquids has moved forward dramatically in the past few years. This is firstly because of the development of new experimental methods which make it possible to directly observe molecular motion in the liquid state (a technologically significant feat, since these dynamics occur in times of less than one million millionth of a second) and secondly very fast and efficient computer programs make it possible to model liquid dynamics accurately. However, many of the liquids that are most important in chemistry and biology do not behave exactly like the common liquids usually studied. For example some liquids spontaneously form large (hundreds of molecules) structures (the living cell being the most imporant, and most complex, example) or change their properties as a result of some external perturbation. Such liquids, called 'complex fluids', are of great importance, being widespread in nature and in foodstuffs (margarine for example) and having important technological applications (liquid crystals are another example). In the research program described here we will extend the methods used successfully to describe common liquids to investigate for the first time the dynamics of this important class of 'complex' fluids. This will contribute to our understanding of chemical processes in materials and life sciences.