D.B. Robinson Distinguished Speaker Series 2013-2014
Andrew Main Lecture title:
Controlling clay suspensions in water and oil using surfactants
Swelling clays, such as montmorillonite, disperse into water but not oil, and tend to form gels at a few percent by weight. The surface properties of the clay can be modified by adsorbing surfactants or polymers, however. We have in particular used stabilisers with amine head groups to modify the behaviour of clay suspensions. In water, this allows for a significant increase of the gelation concentration, and there is evidence of structural change in the suspension associated with this.
Clay can also be dispersed in oil after suitable surface treatment. This allows for full exfoliation of montmorillonite into individual sheets of clay. For rod-like sepiolite clay particles, well-stabilised suspensions were obtained that spontaneously form nematic liquid crystals on increase of concentration. Finally, montmorillonite particles were used to stabilise oil-in-water Pickering emulsions and microcapsules.
Jeroen van Duijneveldt was appointed to a lectureship at the University of Bristol in 1997 and currently is Reader in Physical Chemistry. He obtained his PhD in Utrecht (1994) and came to Bristol as a Ramsay Memorial Fellow (1995). He is a member of the Royal Dutch Chemical Society, the Royal Society of Chemistry (RSC; CChem MRSC), the Society of Chemical Industry and the Institute of Physics (CPhys MInstP). He is treasurer of the RSC Colloid and Interface Science Group and past member and chairman of the RSC Bristol & District Section Committee.
His research group studies soft condensed matter: colloidal suspensions, emulsions, liquid crystals, and polymers. Well-defined model systems allow detailed characterisation, coupling structure (seen in the microscope or using scattering experiments) with phase behaviour and flow properties (rheology). This research field underpins development of a wide range of product formulations, and many of the projects are supported by Industry. A central theme is the use of polymers to control particle interactions, structure and phase behaviour in colloidal suspensions. This work has led to over 60 publications.