Stuart's principal research interest is in developing understanding of the relationships between the structures adopted by molecules at interfaces and the physical properties of these interfaces. Of particular interest have been polymers at the solid-liquid interface of nanoparticles dispersed in water. Such particles have high surface areas to be used for further chemistry, can have useful electronic properties for energy applications and are widely used from personal care formulations through to drug delivery vehicles. The potential economic and environmental impacts of improving our understanding of particulate dispersions are quite high.

Stuart's approach to understanding molecules at surfaces is to bring together various analytical techniques with numerical simulations to help gain the most from the available experimental data. He has extensively used solvent relaxation NMR as a way of characterising near-surface polymer/surfactant complexes has been a workhorse technique for my research in recent years. Through solvent relaxation NMR, in concert with light scattering and small-angle neutron scattering, he demonstrated antagonistic interactions exist between commonly used polymers and surfactants that leads to the destabilisation of nanoparticle dispersions. He also has a long-standing collaboration with US start-up company XiGo Nanotools to design and build bespoke, miniaturised hardware for solvent relaxation NMR and to develop suitable software for controlling the instrument and analysing the data. The instrument is commercially available as the “Acorn Area” with the “AreaQuant” software for measuring the surface area of colloidal dispersions.