Figure 1

Micro-ionic density profiles (averaged over the lateral dimensions), as a function of the normalized separation distance, for the wetting case. The solid and dashed lines represent counterion and co-ion density predictions, respectively, from the present model, whereas the circular and rectangular markers represent the corresponding MD predictions [6]. The corresponding predictions of electrostatic potential are shown in the inset. The oscillations in the ionic density profiles are clear manifestations of the confinement-induced structuration effects, as induced by the discreteness of the solvent molecules. The potential corrections in the mesoscopic description enable one to capture the underlying consequences, without necessarily executing molecular simulations.Reuse & Permissions

Figure 2

Pressure-driven velocity profile (solid line represents MD predictions [6], whereas the “starred“ line represents predictions from the present model) and charge density profile (dotted line with triangular markers) in normalized units, for the wetting case. The physical situation is equivalent to the location of a “no-slip” plane at a distance $\sigma$ from the wall. Within this wall-adjacent layer, the system is virtually immobile. The nonwetting case is presented in the inset. The solid and dashed lines represent velocity and charge density profiles, whereas the dotted line represents hydrodynamic prediction with a no-slip boundary condition. A portion of the velocity profile with steep local gradients adjacent to the wall represents the velocity variation within a two-phase layer, the inception of which is triggered by hydrophobic interactions. The effective slip length is obtained as an extrapolation of the velocity profile prevailing over the remaining extent of the solvent phase. Agreement with MD predictions [6] is excellent.Reuse & Permissions

Figure 3

Effective $\zeta$ potential as a function of the amplification factor $A$, for the nonwetting case. The reported results appear to exhibit a universal trend, irrespective of the details of the flow actuation mechanism (pressure-driven, electro-osmotic, or a combination). For simulating combined effects, axial electric fields of varying strengths are considered, both in the sense of aiding and opposing the imposed pressure gradient. For large ${\psi }_w$, replacement of $\kappa$ with $\frac{\partial (\psi /{\psi }_w)}{\partial z}{|}_w$ identical fits.Reuse & Permissions