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.
Stuart also uses neutron scattering and neutron reflection to obtain detailed structural information on soft-condensed matter systems. He worked on the design, construction and commissioning of a new sample environment for neutron reflection experiments to study the effects of confinement on near-surface structures. Collisions between colloidal particles are one form of confinement, as is lubrication between surfaces. He recently published the designs for the cell along with studies of polyelectrolyte multilayers.
Studying the liquid-liquid interface can pose additional challenges Stuart has made use of microfluidic techniques to create of stable, high surface area emulsions. These emulsions are model systems to explore the uses of NMR for the characterisation of the drop size of emulsions as well as templates for further synthesis.
Stuart undertook his PhD research into the kinetics of RAFT-mediated living polymerisations jointly between the CSIRO, the Cooperative Research Centre for Polymers and the Key Centre for Polymer Colloids. Following two years' post-doctoral research at the University of Melbourne with the AFM, sonochemistry and nanoparticle groups, he moved to Bristol to take up a Marie Curie Individual Fellowship. He was appointed to the position of Lecturer in Polymer Chemistry at the University of Bristol in 2009 and Senior Lecturer in Chemical Engineering at the University of New South Wales in 2013.
Stuart is also active in the Free and Open Source Software movement. He maintains a range of data analysis and visualisation packages for the Debian project and is a regular contributor to free software projects.