Anisotropic Stick-Slip Behavior of Aqueous Drops on Lubricated Chemically Heterogeneous Slippery Surfaces

Slippery but tough - the rapid fracture of lubricated frictional interfaces

We study the onset of friction for rough contacting blocks whose interface is coated with a thin lubrication layer. High speed measurements of the real contact area and stress fields near the interface reveal that propagating shear cracks mediate lubricated frictional motion. While lubricants reduce interface resistances, surprisingly, they significantly increase energy dissipated, $Γ$, during rupture. Moreover, lubricant viscosity affects the onset of friction but has no effect on $Γ$. Fracture mechanics provide a new way to view the otherwise hidden complex dynamics of the lubrication layer.

Numerical and Experimental Investigation of Static Wetting Morphologies of Aqueous Drops on Lubricated Slippery Surfaces Using a Quasi-Static Approach

Due to the slow dynamics of the wetting ridge, it is challenging to predict the wetting morphology of liquid drops on thin lubricant coated surfaces. It is hypothesized that when a drop sinks on a lubricated surface, quasi-static wetting morphology can be numerically computed only from the knowledge of interfacial energies, lubricant thickness, and drop volume. We used Surface Evolver software for the numerical computation of the interface profiles for a four-phase system. For the experiments, we used drops of 80 wt% formamide on silicone oil coated substrates with varying lubricant thickness,…

Slippery or sticky ! Control of wrinkling patterns by selective adhesion

Wrinkling patterns at the metallized surface of thin polymer films are shown to be sensitive to the sticky or slippery character of the polymer/substrate interface (titanium coating, polystyrene film and coated silicon substrate). Selective prefered wrinkle orientation and amplitude are achieved. Existing theoretical models are expanded to specific boundary conditions (adhesive vs slippery) and rationalize these observations.

Guided droplet transport on synthetic slippery surfaces inspired by a pitcher plant

We show how anisotropic, grooved features facilitate the trapping and directed transport of droplets on lubricated, liquid-shedding surfaces. Capillary action pins droplets to topographic surface features, enabling transport along the feature while inhibiting motion across (or detachment from) the feature. We demonstrate the robustness of this capillary-based mechanism for directed droplet transport on slippery surfaces by combining experiments on synthetic, lubricant-infused surfaces with observations on the natural trapping surface of a carnivorous pitcher plant. Controlling liquid navigatio…

Effects of soft interactions and bound mobility on diffusion in crowded environments: a model of sticky and slippery obstacles

Crowded environments modify the diffusion of macromolecules, generally slowing their movement and inducing transient anomalous subdiffusion. The presence of obstacles also modifies the kinetics and equilibrium behavior of tracers. While previous theoretical studies of particle diffusion have typically assumed either impenetrable obstacles or binding interactions that immobilize the particle, in many cellular contexts bound particles remain mobile. Examples include membrane proteins or lipids with some entry and diffusion within lipid domains and proteins that can enter into membraneless organe…

胶体悬浮液滴在注油滑移表面上的蒸发

Evaporation of Colloidal Suspension Droplets over Oil-infused Slippery Surfaces

本文研究了不同浓度胶体液滴在仿生图案化注液滑移基底（LISS）上的蒸发干燥过程，发现注入油层厚度（hE）强烈影响钉扎程度和沉积形态，长时间蒸发可实现均匀沉积。