Soft meets hard: a microscopic view of the freeze-thaw stability of Pickering emulsions

Abstract: Particle stabilised emulsions are widely used in the food and personal care industries and are present in common household products such as homogenised milk. It is therefore important to characterise the behaviour and stability of these composites under the influence of processes used both in industry and in daily life, such as freezing and thawing. Using confocal microscopy, we investigate the microscopic changes in structure of water-in-oil Pickering emulsions undergoing freeze-thaw cycles. We explore the effects of droplet size and cooling rate on both the behaviour of the emulsions during the freeze-thaw cycle and on the post-thaw structure. We also consider inhomogeneous sample cooling/heating and the resultant biliquid-foam patches which are produced under these conditions. These results help us to understand how hard materials, such as ice crystals, interact with soft materials at the microscopic level.