The project is to understand fundamental structure-performance relationships of chemical demulsifiers in water-in-crude oil (w/o) systems. In particular, to understand how different polymers (demulsifiers) affect structural behaviour and stability of model well characterised w/o microemulsion systems. Studies of crude oil demulsifier performance in the literature are limited, and there are no examples of SANS being used for this purpose. SANS is the ideal technique to use, especially when employing contrast matching to highlight different domains, components and layers. This SANS proposal forms an essential part of a PhD project fully-funded by Croda Europe Ltd.