Direct Experimental Evidence of Slip in Hexadecane: Solid Interfaces

Abstract

The boundary condition for the flow velocity of a Newtonian fluid near a solid wall has been probed experimentally with a novel setup using total internal reflection-fluorescence recovery after photobleaching leading to a resolution from the wall of the order of 80 nm. For hexadecane flowing on a hydrocarbon/lyophobic smooth surface, we give what we think to be the first direct experimental evidence of noticeable slip at the wall. We show that the surface roughness and the strength of the fluid-surface interactions both act on wall slip, in antagonist ways.

Apparent Slip Due to the Motion of Suspended Particles in Flows of Electrolyte Solutions

“…Consequently, we cannot assume that the Peclet number, P e = U/U k B T = U a/D, is necessarily large and thermal motion cannot in general be neglected. However, in the experiments reported to date, velocity measurements are cross correlated (as in [9]) or averaged (as in [11]) so that the random thermal motion disappears, and we will therefore not consider it in this paper.…”

“…Over the last few years, a number of pressure-driven flow [7,8,9,10], shear-flow [11], and squeeze-flow experiments [12,13,14,15,16,17,18] showing a response interpretable as some degree of slip for partially wetting liquids have been reported. Molecular dynamics simulations of Lennard-Jones liquids have also shown that slip can occur, but only at unrealistically high shear rates [19,20].…”

“…We are only aware of two such previous works. Pit et al [11] measured velocities in shear flow of hexadecane over a smooth surface using a technique based on fluorescence recovery after photobleaching (see also [22]). …”

Force measurements with the atomic force microscope: Technique, interpretation and applications

“…A possible slip was only discussed in the mainstream literature for polymer melts [1007,1008]. Recent experiments, however, indicated that fluids might slip past smooth surfaces [1009][1010][1011][1012][1013][1014]. The hydrodynamic boundary condition to describe slippage is [1015] …”

A constrained particle dynamics for continuum-particle hybrid method in micro- and nano-fluidics

“…The main reasons for those differences include the increasing ratio of surface to volume and the important effects of the interfaces between fluid and solid or two-phase flows [2]. Especially, in the fluid-solid interface, there may exist slip boundary conditions [3,4]. The slip boundary conditions are difficult to be treated at the level of continuum dynamics.…”