Department Seminar of Vaknin Yanin - Electrokinetics, Dynamics & Stability of Single and Two Interacting Janus Particles Under Gravity
School of Mechanical Engineering Seminar
Monday 1.11.2023 at 14:00
ZOOM SEMINAR
Electrokinetics, Dynamics & Stability of Single and Two Interacting Janus Particles Under Gravity
Vaknin Yanin
M.Sc. student of Prof. Touvia Miloh
School of Mechanical Engineering, Tel Aviv University, Tel Aviv, Israel
One of the simplest inhomogeneous geometries in electrokinetics is that of a Janus sphere, which comprises two hemispheres with differing properties. In our research, we explore the non-linear dipolophoretic motion (dielectrophoresis combined with induced-charge electrophoresis) of a nano/micro Janus particle when exposed to a spatially uniform ambient AC electric field, both in the presence and absence of a gravity field. In our case, we consider the special case of a "metallodielectric" Janus sphere, comprises of two half-spheres - one metallic and the other dielectric.
Both the electrostatic and hydrodynamic problems are solved for the unbounded case (no walls) under the conventional Poisson-Nernst-Planck (PNP) model by assuming a “weak-field” and a “thin” Debye layer. Furthermore, we analyze the resulting dipolophoretic motion of two adjacent interacting Janus particles which are exposed to a spatially uniform ambient AC electric field (again with or without gravity). In addition to the electrostatic and hydrodynamic forces applied on a single sphere, we also calculate the induced velocity at the center of one sphere due to the Stokes motion of the other sphere by means of Faxen. In order to analyze the dynamics and stability of these complex phenomena, we employ a combination of analytical and numerical methods.
The implications of our findings are vast, with potential applications ranging from drug delivery systems to the design of probes based on Janus nanoparticles, which can provide directional data about cell-particle interactions.
