２０１７年８月９日 植松祐輝氏

日時：２０１７年８月９日（水）　１１：００〜１２：３０
場所：首都大学東京　８号館３０１号室
講師：植松祐輝氏 (九州大学・ベルリン自由大学)
題目：Electro-osmosis and its dependence on the interfacial properties of water

要旨：The Poisson-Boltzmann and Stokes equations describing the electric double layer with inhomogeneous dielectric and viscosity profiles in a lateral electric field are analyzed.We perform linear and nonlinear analysis to electro-osmosis, and derive that in the limit of strongly charged surfaces and low salinity, the electrokinetic flow magnitude follows a power law as a function of the surface charge density. Remarkably, the power-law exponent is determined by the interfacial dielectric constant and viscosity, the latter of which has eluded experimental determination. Our approach provides a novel method to extract the effective interfacial viscosity from standard electrokinetic experiments. We find good agreement between our theory and experimental data. We also examine the different types of boundary condition for velocity field, and show that finite-viscosity-layer model is more realistic than the usual slip boundary condition by comparing the experimental data.