I run the Edinburgh Complex Fluids Partnership (ECFP) which facilitates knowledge transfer of the research carried out by the Institute of Condensed Matter and Complex Systems (ICMCS). Research topics including the flow of dispersions and emulsions, the stability of colloid-polymer gels and the behaviour of bacteria in complex media are all relevant to the formulation and processing industries. Industry can work with ECFP through a variety of models including research projects, consultancy, student sponsorship and service work.
On the academic side, I have been utilizing the order intrinsic to liquid crystals to self-assemble colloidal systems. Mixing colloids into a nematic solvent we find that the type of structure formed depends on the volume fraction. Collaborating with Davide Marenduzzo we have used simulations to determine the form of defect lines in the composite. Interestingly we find that defect lines percolate through the composite at volume fractions higher than 20\% and create a stiff gel that exhibits self-healing characteristics.
Previously, I worked in the field of optical tweezers to study particle dynamics in various media. We successfully used such a technique to measure the effective temperature of a colloidal glass. As well as applying optical interferometry to study translational dynamics, we developed techniques to access rotational dynamics using birefringent particles. Using optical tweezers I also demonstrated that waveplate-like behaviour was primarily reponsible for the transfer of optical torque to birefringent nematic liquid crystal droplets held in an optical trap. Trapping chiral nematic liquid crystalline droplets, the effect of selective reflection on axial optical trapping forces was also studied. In addition, we studied colloid behaviour in nematic liquid crystals and demonstrated that isotropic particles could be trapped and manipulated in liquid crystalline media. By dragging a colloid through the liquid crystal, we measured the effective viscosities experienced by a particle subject to drag flow in both parallel and perpendicular with respect to the director of a nematic liquid crystal.
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