Search

Superhydrophobic surfaces have great potential for application in self-cleaning and oil/water separation. However, the large-scale practical applications of superhydrophobic coating surfaces are impeded by many factors, such as complicated fabrication processes, the use of fluorinated reagents and noxious organic solvents and poor mechanical stability. Herein, we describe the successful preparation of a fluorine-free multifunctional coating without noxious organic solvents that was brushed, dipped or sprayed onto glass slides and stainless-steel meshes as substrates. The obtained multifunctional superhydrophobic and superoleophilic surfaces (MSHOs) demonstrated self-cleaning abilities even when contaminated with or immersed in oil. The superhydrophobic surfaces were robust and maintained their water repellency after being scratched with a knife or abraded with sandpaper for 50 cycles. In addition, stainless-steel meshes sprayed with the coating quickly separated various oil/water mixtures with a high separation efficiency (>93%). Furthermore, the coated mesh maintained a high separation efficiency above 95% over 20 cycles of separation. This simple and effective strategy will inspire the large-scale fabrication of multifunctional surfaces for practical applications in self-cleaning and oil/water separation.

Superhydrophobic surfaces with structure-dependent switchable wettability have recently drawn considerable attention due to their special applications in droplet manipulation, rewritable liquid patterns, friction control, etc. However, it still remains a great challenge for developing tunable superhydrophobic surfaces with multiple functions including friction control through a facile strategy. Here, we apply a templating approach to fabricate switchable superhydrophobic surfaces that can reversibly transit between high-adhesion superhydrophobic and hydrophobic states by dynamically controlling the morphology of the micro/nanostructures. Notably, due to the dynamically controllable micro/nanostructures and wettability, the superhydrophobic surface shows multiple functions. The superhydrophobic surface under different wetting states can serve as a droplet capturer or reaction platform to achieve droplet manipulation. Moreover, the friction coefficient of the superhydrophobic surface can be switched between ∼ 0.4 and ∼ 0.13, demonstrating the application potential in friction control. This work offers a promising multifunctional superhydrophobic platform with dynamically controllable morphology of micro/nanostructures and wetting behaviors for the applications of droplet manipulation and friction control.

There has been substantial recent interest with respect to the broad potential applications of superomniphobic surfaces, but it remains enormously challenging to enhance the dynamic stability of such surfaces impacted by high-pressured droplets. Herein, a robust superomniphobic surface with dual-scale re-entrant structures (DRSs) has been designed and fabricated through a facile combination of magnetic particle-assisted self-assembly and a dip-coating technique. Compared to superomniphobic surfaces with single-scale re-entrant structures, this superomniphobic surface with DRSs shows highly improved repellency against the impact from different high-pressured droplets, a property which is furnished by the extension of three-phase contact lines, the increase in local geometric angles, and the formation of additional air pockets. Furthermore, the superomniphobic surface can serve as a platform to well maintain lubricating fluid so as to realize a photoresponsive slippery surface wherein near-infrared light can be used to manipulate various liquid droplets with a large range of volumes. Overall, this study provides a strategy for obtaining the robust superomniphobic and photoresponsive slippery surfaces through the DRS design, which provides a new insight into enhancing the dynamic stability of superomniphobic surfaces and also demonstrates the application of slippery surfaces for droplet manipulation.