| 초록 |
In the charge-related wetting phenomena of the micron-sized or smaller, closed system, the assumption of infinite domain of Poisson-Boltzmann equation may not be satisfied. Then, we cannot neglect the finiteness of the number of ions and cannot define the bulk position for the system. In the present work, semi-spherical electrolyte droplet on the electrode is considered. We use a different governing equation to include the ion number constraints by combining the Poisson equation and Nernst-Planck equation(PNPc). This is a more general form of the Poisson-Boltzmann equation (PB). Due to the non-linearity of equations, numerical approach is taken. It is based on a finite-difference solution on each governing equation on the spherical coordinate. The concrete distribution of the electrostatic potential inside the droplet is analyzed for different parameters including the inverse Debye length (κR), and the electrostatic force exerted on the drop surface is calculated for the prediction of the deformation of the drop surface near the contact line by using the relation between the curvature and the normal stress. It is shown that the macroscopic shape change in electrowetting can be made by the electric contribution without the molecular contribution. |
