Continuous Directional Water Transport on Integrating Tapered Surfaces

Abstract

years, the transport distance is always limited by the short gradient length: larger gradient driving force and larger gradient length are contradictory. This limitation impedes the application of water transport in a wide range of practical settings. Clearly, introducing of external energy, such as light, [5] temperature, [6] magnetic field, [7] electric field, [8] and vibration [9] can break the limitation. However, complexity of manufacturing technologies and waste of energy restrict the applications of such design strategies. Therefore, it is essential to develop a simple method to achieve continuous directional and long-range water transport without extraneous energy.Here, we report a continuous directional and long-range transport of fog droplets on integrating tapered surface (ITS) inspired by spider silk and butterfly wing. [2,10] Fog droplets first transport on single tapered structure from tip to bottom propelled by Laplace pressure and form liquid film at the joint. Then, a new phenomenon occurs that the liquid film switches periodically between convex-continuous and concaveintermittent due to synergism of Laplace pressure gradient and wetting gradient, which promotes the rapid surface reconstruction and fog droplet collection. The combination of continuous, directional, long-range transport of fog droplets and rapid surface reconstruction facilitates highly effective water harvesting task. We envision that this basic design strategy can be applied to artificial fluid transport systems, water-collecting devices and systems, etc.

Bioinspired Unidirectional Liquid Transport Micro-nano Structures: A Review

“…6a) [39] . By controlling the electric current in the electrochemical etching process, a designed integrating tapered wire can be achieved with continuous directional water transporting ability [56] . A star-shaped hydrophilic pattern can be fabricated with patterned UV exposure, where its sharp wedged edges can directionally aggregate fog more efficiently than round edges [57] .…”

Special Wettability Materials Inspired by Multiorganisms for Fog Collection

“…However, the distance to which these surfaces transport water is always limited by the shorter gradient length, because the larger gradient driving force contradicts the larger gradient length. Inspired by spider silk and butterfly wing, Feng et al [154] prepared continuous, directional, long-distance fog droplet transport system of integrating tapered surface (ITS), which consists of regular tapered knots. In order to control the surface wettability of copper needles prepared by anodic oxidation method, a wettability gradient is formed on ITS surface by lowering the liquid level height, and the wettability is gradually enhanced when the contact angle decreases from the top to the bottom (Figure 20a).…”

Progress in Bioinspired Dry and Wet Gradient Materials from Design Principles to Engineering Applications

“…The system is made by anodizing methods introduced by nano-needles of copper hydroxide. Synergism of Laplace pressure and wetting gradient play essential roles in the water collection process and the continuous, directional, and long-range transport of fog droplets ( Feng et al., 2020 ). Hou et al., inspired by spider silk and cactus, fabricated a multilevel-structure bioinspired fiber with multigradients.…”