Directional transport of droplets impacting on superhydrophobic opening triangular groove surfaces

Abstract

Directional droplet transport is of great importance to various processes including heat transfer, water harvesting and microfluidics. Here, a facile superhydrophobic opening triangular groove surface was proposed, and the directional transport behavior of droplets impacting on the surface was observed. The results show that the essence of the directional transport on the opening triangular groove surface can be attributed to the interaction between the impinging droplet and the groove sidewall, and the directional transport distance is regulated by the contact area during the interaction. Further, by controlling the depth of triangular groove, the triangular opening angle, the impacting point position and the Weber number, the contact area between the droplet and the groove sidewall during the interaction can be changed, leading to the variation of directional transport distance. This study provides a new method for directional droplet transport on superhydrophobic surfaces and offers more options for the manipulation of droplet behavior.

Controllable self‐transport of bouncing droplets on ultraslippery surfaces with wedge‐shaped grooves

“…Wang et al 27 identified the factors affecting the distance of transport and provided guidelines for wedge‐shaped design for optimized spontaneous liquid transport. It is confirmed that wedge angle and groove depth are two important indicators of wedge‐shaped structures 28 . Similar to superhydrophobic surfaces, water droplets also show behaviors such as deposition, total bounce, and splashing on impact on SLIPS 29,30 .…”

“…Wang et al 27 that wedge angle and groove depth are two important indicators of wedge-shaped structures. 28 Similar to superhydrophobic surfaces, water droplets also show behaviors such as deposition, total bounce, and splashing on impact on SLIPS. 29,30 A basic question that arises if one wants to use SLIPS for surface cleaning is as follows: is there a possibility to control the self-transport behavior of droplets on SLIPS with wedge-shaped structures?…”