About the Research

An understanding of colloidal particles at interfaces is critical to a variety of phenomena of industrial significance. Fluid-fluid interface-containing particles include oil-water, air-water, oil-oil, air-oil and water-water interfaces (1). Janus liquid marbles, for example, can be prepared by coalescing a liquid water droplet with an oil droplet in the presence of omniphobic particles and can then be used to carry out reactions that take place at the oil-water interface (2). Methods are being developed for manipulating such non-wetting droplets (termed ‘liquid marbles’) which can be applied in biological detection and clinical diagnosis as well as in microreactors for material fabrication and chemical reactions (3). Light and magnetic effects can be used to create a Pickering emulsion microreactor by co-adsorption of light-sensitive titania (TiO₂) and super paramagnetic iron oxide (Fe₃O₄) nanoparticles at the oil-water interface of emulsion droplets (4), enabling improved versatility in this class of microreactor.

Flow chemistry is of growing interest to the pharmaceutical among other industries. Its advantages include continuous processing, scalability, reduced solvent use and finer control of reaction products. Pickering emulsions have been explored in the Binks group as part of an EU project looking at a ‘compartmentalised smart factory’ approach involving heterogeneous palladium (Pd) catalysts and biocatalysts in catalytic cascade synthesis of active pharmaceutical ingredients (APIs) (5). Interfacial catalysis in a Pickering emulsion has also been investigated in the group to elucidate their mechanism with the aim of moving towards solvent-free epoxidation reactions (Figure 1) (6). Continuous enzymatic or homogeneous catalysed reactions are also being explored in non-aqueous Pickering emulsions (7).

In the life sciences, Pickering emulsions have raised interest for bone tissue engineering applications with the possibility of forming biocompatible and biodegradable porous scaffolds with adjustable pore structure (8). Water-in-water (w/w) emulsions are attractive micro compartmentalised systems for applications in the life sciences including drug delivery and encapsulation as well as synthesis due to biocompatibility (9).

Current projects in the Binks group at the University of Hull include stabilisation of emulsions with polyelectrolyte complexes or organic pigments, the effects of polymers and surfactants on oils and oil-water emulsions, aqueous and oil-based foams and catalysis in microparticle stabilised emulsions.