Emulsions with nanoparticles for new materials

The project is a joint work with the partners from Institute of Fluid Mechanics and Heat Transfer (ISW) of Graz University of Technology, Austria, the Laboratory of Chemical Physics and Engineering (LCPE) of the University of Sofia, Bulgaria, and the Department of Mechanics and Physics of Fluids (DMPF) of the Polish Academy of Sciences in Warsaw, Poland. The work is dedicated to explore new and promising directions for the fabrication of nano-composites (colloidosomes, microcapsules, core-shell and other composite particles), as well as nano-structured surfaces and porous layers, using emulsion droplets as precursors and/or templates. The considered procedures involve the formation of emulsions, and especially emulsions stabilized by solid particles (Pickering emulsions), where the main relevant effects for the process of emulsification and the emulsion stability in the presence of solid particles are investigated. Three different emulsification methods are considered experimentally as well as analytically and numerically, namely a narrow-gap homogenizer, the liquid jet break-up technique and membrane emulsification. In the first two methods, the emulsification process is associated with a stepwise break-up of the oil phase into smaller droplets. In the latter, a mono-disperse emulsion is produced by driving the oil phase through microprous membranes into the carrier phase. The here obtained data are used to further devop and validate theoretical models for the prediction of the size distribution of the produced drops. The interaction of nanoparticles at interfaces that lead to the formation of dense adsorption layers and formation of stable Pickering emulsions is studied by carrying out experiments with single drops, which allow direct optical observation and quantitative analysis of the processes such as kinetics of particle adsorption, film stability, drop-drop coalescence, etc. The results of these single drop experiments contribute to a better understanding of the lateral capillary forces between particles at emulsion interfaces, and serve to revisit the theoretical modeling of this interaction.