Modeling and Simulations of Soft Matters

Abstract

The electrostatic interaction has been extensively studied in electrolytes and many soft matters. However, not enough attention has yet been paid on the molecular interactions in charged fluid systems. Particularly, the ion-dipole interaction gives rise to the solvation shell around each charged particle, whose characteristic energy much exceeds the thermal energy kBT. The resultant solvation interaction drastically affects phase transitions and structure formations, sometimes leading to mysterious effects. I will discuss such aspects in electrolytes, polyelectrolytes, ionic surfactants, colloids, and so on. In particular, some unique effects appear with addition of salt composed of hydrophilic and hydrophobic ions in mixtures of water+less polar component, where such ion pairs behave antagonistically in the presence of composition heterogeneities.

About the speaker

Prof. Akira Onuki received his PhD in Physics from University of Tokyo in Japan and later was assistant in Physics at Kyusyu University. Currently, he is a professor at Department of Physics of Kyoto University. He has been studying phase transition dynamics in various systems including fluids, solids, and superfluids. He wrote ”Phase Transition Dynamics” (Cambridge, 2002), which give precise mathematical explanations of various theories treating a broad range of physical systems. He has recently begun to work on the charge effects in soft matters combined with the solvation effects. He is also working on two-phase hydrodynamics on the basis of the dynamic van der Waals theory presented by himself. Some predictions are being made on Marangoni effects in binary fluid mixtures.