Drop Cargo Transfer via Unidirectional Lubricant Spreading on Peristome-Mimetic Surface

Abstract

To promote drop mobility, lubricating the gap between liquid drop and solid surface is a facile method which has been widely exploited by nature. Examples include lotus and rice leaves using entrapped air to "lubricate" water and Nepenthes pitcher plant using a slippery water layer to trap insects. Inspired by these, here, we report a strategy for transporting drop cargoes via the unidirectional spreading of immiscible lubricants on the peristome-mimetic surface. Oleophilic/hydrophobic peristome-mimetic surfaces were fabricated through replicating three-dimensional printed samples. The peristome-mimetic surface, via unidirectional immiscible hexadecane spreading, can transport a wide diversity of drop cargoes over a long distance with no loss with controllable drop volumes and velocities, hence mixing multiphase liquids and even reacting liquids. We anticipate this unidirectional drop cargo transport technique will find use in microfluidics, microreactors, water harvesting systems, etc.

Bioinspired Surface with Superwettability for Controllable Liquid Dynamics

“…achieved no‐loss and directional transport of a wide range of droplet cargoes (Figure 5b). [ 75 ] Multiphase liquid microfluidics and even liquid microreactors can be easily implemented. In addition, surface curvature is another crucial factor that affects liquid dynamics.…”

“…Reproduced with permission. [ 75 ] Copyright 2018, American Chemical Society. c) The time‐dependent asymmetric spreading dynamics of droplets on a curved peristome‐mimetic PVA hydrogel surface.…”

“…[ 23 ] In addition, no‐loss, fast, long‐distance, and directional liquid transport, including a wide diversity of liquids or drop cargoes, can be achieved on peristome‐mimetic surfaces in open systems. [ 7,75 ] Based on this result, multiphase liquid microfluidics, liquid‐liquid separation (Figure 8e), [ 77 ] and even liquid microreactors (Figure 8f) [ 75 ] can be easily implemented.…”

Surface-Tension-Confined Channel with Biomimetic Microstructures for Unidirectional Liquid Spreading

“…On the one hand, as shown in Figure 4b, i, the advancing angle θ A of liquid on the stage approximates to zero due to the complete hydrophilic property of the STC channel. Affected by the strong capillary rise in RC, the precursor is first imbibed into microcavities before the movement of the major liquid film, and the forward transport is enhanced obviously compared to liquid wetting on smooth channel owing to the transition of liquid/solid interface to liquid/liquid interface (Figure 4b, ii,iii) [43]. The liquid imbibition and filling process in the microcavity can be simplified to the capillary flow in an open channel with wedge corners, which are relevant to the pit dimensions and the wedge angle of front corner [44,45].…”

Programmable droplet manipulation and wetting with soft magnetic carpets

“…Although previous work has successfully demonstrated a patterned wetting surface, this has only been achieved via the microfabrication of static patterns ( 22 , 23 ). Furthermore, the ability to reversibly locate and manipulate multiple droplets over large distances has been challenging ( 10 , 24 , 25 ) because of the static nature of the manipulation designs ( 26 , 27 ). Some of the methods based on magnetic fields suffered from contamination in the used magnetic particles, requiring a purification step after transportation ( 28 , 29 ).…”