Wetting Ridge‐Guided Directional Water Self‐Transport

Abstract

Directional water self‐transport plays a crucial role in diverse applications such as biosensing and water harvesting. Despite extensive progress, current strategies for directional water self‐transport are restricted to a short self‐driving distance, single function, and complicated fabrication methods. Here, a lubricant‐infused heterogeneous superwettability surface (LIHSS) for directional water self‐transport is proposed on polyimide (PI) film through femtosecond laser direct writing and lubricant infusion. By tuning the parameters of the femtosecond laser, the wettability of PI film can be transformed into superhydrophobic or superhydrophilic. After trapping water droplets on the superhydrophilic surface and depositing excess lubricant, the asymmetrical wetting ridge drives water droplets by an attractive capillary force on the LIHSS. Notably, the maximum droplet self‐driving distance can approach ≈3 mm, which is nearly twice as long as the previously reported strategies for direction water self‐transport. Significantly, it is demonstrated that this strategy makes it possible to achieve water self‐transport, anti‐gravity pumping, and chemical microreaction on a tilted LIHSS. This work provides an efficient method to fabricate a promising platform for realizing directional water self‐transport.

Sr(II) and Ba(II) Alkaline Earth Metal–Organic Frameworks (AE-MOFs) for Selective Gas Adsorption, Energy Storage, and Environmental Application

“…The inorganic units can be metal cations or clusters; the latter is widely described as secondary building units (SBUs) with different shapes and sizes. Because of the extraordinary variability degree of building blocks, their enormous surface areas, and the multiple ways of surface functionalization and modification, MOFs have considerable potential in many application areas, such as gas storage [ 1 , 2 , 3 , 4 ] and separation [ 5 , 6 ], heterogeneous catalysis [ 7 , 8 , 9 , 10 ], drug delivery [ 11 , 12 , 13 ], water [ 14 , 15 , 16 , 17 ] and sensor technology [ 18 , 19 ], magnetic refrigeration [ 20 , 21 , 22 ], or conductive matrix for sulphur in lithium-sulphur (Li-S) batteries [ 23 , 24 , 25 , 26 ].…”

Janus Fabric with Asymmetric Wettability for Switchable Emulsion Separation and Controllable Droplets with Low Friction

“…Compared with monofunctional membranes, Janus smart membranes can simply realize the opposite separation synergistically by simple operation, resulting from an intrinsic inner driving force of Janus membranes. At present, many strategies have been applied to fabricate Janus membranes, such as floated coating and deposition, unidirectional segregation, sequential electrospinning, thiol–ene click chemistry, vapor treatment, photopolymerization, photografting, laser structuring, and so on. − However, this has to be settled urgently for preparation of a membrane by a facile approach on various alternative substrates, and a Janus membrane is deficient for separating various emulsions due to inconspicuous wetting asymmetry. As for separating a water-in-oil emulsion, Janus membrane surfaces lack instantaneous wettability, which increases the transmembrane resistance during slow penetration, resulting in a lower flux for a large-scale application.…”

Underwater Oleophobic Electrospun Membrane with Spindle-Knotted Structured Fibers for Oil-in-Water Emulsion Separation

“…38 Inspired by the mosquito bite-induced bulge and the N. alata plant's transporting water behavior, Wang et al, through femtosecond laser direct writing and lubricant infusion, fabricated a lubricant-infused heterogeneous superwettable surface on the polyimide (PI) film, which successfully realized directional water self-transport. 39 Jiang et al utilized the template method to fabricate needle arrays of poly-(dimethylsiloxane). Similar to cactus spines in nature, the needle-like arrays could collect tiny oil droplets from the emulsion.…”

“…Water-collecting mechanisms on biological surfaces, such as the carapace of stenocara beetles, the capturing silk of cribellate spiders, and cactus spines, serve as an inspiration for materials with structures that exert directional movement on droplets . Inspired by the mosquito bite-induced bulge and the N. alata plant’s transporting water behavior, Wang et al, through femtosecond laser direct writing and lubricant infusion, fabricated a lubricant-infused heterogeneous superwettable surface on the polyimide (PI) film, which successfully realized directional water self-transport . Jiang et al utilized the template method to fabricate needle arrays of poly­(dimethylsiloxane).…”