Structured surfaces for a giant liquid slip.

Maximizing the giant liquid slip on superhydrophobic microstructures by nanostructuring their sidewalls.

In an effort to maximize the liquid slip on superhydrophobic surfaces, we investigate the role of the nanoscale roughness on microscale structures by developing well-defined micro-nano hierarchical structures. The nonwetting stability and slip length on the dual-scale micro-nano structures are measured and compared with those on single-scale micro-smooth structures. A force balance between a li...

Giant slip at liquid-liquid interfaces using hydrophobic ball bearings.

Liquid-gas-liquid interfaces stabilized by hydrophobic beads behave as ball bearings under shear and exhibit a giant slip. Using a scaling analysis and molecular dynamics simulations we predict that, when the contact angle θ between the beads and the liquid is large, the slip length diverges as Rρ(-1)(π-θ)(-3) where R is the bead radius, and ρ is the bead density.

Effect of Geometric Parameters of Superhydrophobic Surface on Liquid Slip

In this paper, we experimentally study how geometric parameters of textured hydrophobic surfaces affect a liquid slip, empowered by a custom-tuned microfabrication procedure that produces regular micro-patterns of posts and grates on an entire 4” wafer with a good size uniformity and no defect. A pitch of the patterns and a gas fraction of the structured surface are independently controlled, an...

Slip flow over structured surfaces with entrapped microbubbles.

On hydrophobic surfaces, roughness may lead to a transition to a superhydrophobic state, where gas bubbles at the surface can have a strong impact on a detected slip. We present two-phase lattice Boltzmann simulations of a Couette flow over structured surfaces with attached gas bubbles. Even though the bubbles add slippery surfaces to the channel, they can cause negative slip to appear due to t...

A New Method for Determination of Critical Slip Surfaces in Earth Slopes