CONDITIONS FOR CREATING THIN LIQUID LAYERS AT THE CONTACT SURFACE OF TWO OTHER LIQUIDS Agnieszka Słowicka Zbigniew A. Walenta Institute of Fundamental Technological Research Polish Academy of Sciences

Aim- Nanomaterials of structure as shown The emulsion with thin layers of third substance at the surface between oil and water The structure of nanomaterial after removing water and oil

Molecular Dynamics Simulation Liquid – an ensemble of molecules Interaction between molecules Electrostatic interactionvan der Waals interaction Coulomb potentialLennard - Jones potential The program „Moldy” by Keith Refson used for simulation.

Models of molecules and interactions Diagram of the Lennard-Jones potential Molecule of waterMolecule of oilMolecule of the third fluid

180 amu OilWater Parameters of the Lennard-Jones potential + H O + H 18 amu

t = 0 ps t = 9 ps t = 13 ps Molecules of water = 1000 Diameter of the droplet ~  A 32 Formation of water droplet in vacuum Oscilation period = 26 ps ~ diameter of oil droplet average speed of molecules

Simulation of emulsification process t = 0 ps t = 5 ps t = 13 ps Temperature = 300 K Molecules of water = 7000 Molecules of oil = 1000 Diameter of oil droplet ~

t = 0 ps t =48 ps Temperature = 300 K Molekules of water = 2614 Molekules of oil = 257 Molecules ofsoap = 252 Diameter of oil droplet ~  A 20 Simulation of three liquids t = 123 ps

The molecular dynamics seems to be the best tool to simulate physical processes on a nanoscale in liquids. Formation of water droplet in vacuum and oil droplet in water have been simulated successfully. The addition of soap, expected to remain at the surface of oil, leads to destruction of oil droplets. Now we look for other substances which would stay at the surface of the droplets and would not destroy them. Conclusions