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

Abstract

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 navigation on synthetic surfaces promises to unlock significant potential in droplet-based technologies. Our observations also offer novel insight into the evolution of the Nepenthes pitcher plant, indicating that the 'pitfall' trapping mechanism is enhanced by the lubricant-infused, macroscopic grooves on the slippery peristome surface, which guide prey into the trap in a way that is more tightly controlled than previously considered.

Simultaneous measurement of time‐of‐wetness and electrolyte concentrations with IDE sensors by evaluation of impedance spectra using an artificial neural network

“…The fast drop of the electrolyte concentration for the 40° angle at 80% humidity can be attributed to a fast volume change but a slow change in the surface coverage, which may be related to a change of the droplet evaporation mode from evaporation with constant contact angle to evaporation with a constant contact radius 18 . Further investigations could clarify if there is an influence of a guided transport of small droplets between the electrode digits on the measurement signal 19 …”

Investigation and modelling of edge corrosion of e‐coated galvanized steel with respect to the spatial edge orientation

“…However, especially bottom horizontal edges (hb) do exhibit a characteristic feature, called droplet pinning. [38,39] As electrolyte droplets are growing during the salt spray phase until they reach a mass where they no longer stick to the surface and roll down the sample, droplets in their path are carried off. When reaching the horizontal edge, the electrolyte is pinned and forms a bead of liquid or droplets.…”

“…When reaching the horizontal edge, the electrolyte is pinned and forms a bead of liquid or droplets. [38,39] The size is dependent on the angle of the incline. This means, while on vertical edges, pinning or sticking of droplets to the edge is a result of microscopic structures as surface roughness or particles, on horizontal edges droplets are pinned at the edge.…”

Anisotropy-induced directional self-transportation of low surface tension liquids: a review

“…59,61 Experimental and numerical studies have characterized the directional transportation of these unique structures in terms of surface wettability, as well as the viscosity and surface tension of the liquid. [66][67][68][69][70] In 2017, Chen et al 6 also fabricated bio-inspired unidirectional liquid spreading surfaces using inclined UV exposure of SU-8 photoresist. Various arc-curvatures and wedge angles were fabricated to investigate the effect of structural features on the spread mechanism (Fig.…”