Fog-harvesting devices (FHDs) have been widely explored and applied to alleviate the shortage of fresh water. However, during the fog collection process, how to maintain a balance between fog capture and water removal behaviors to enhance the water collection rate still remains a challenge. Herein, inspired by the Stenocara beetle, we combined a beetle-like Janus surface and the conventional cross-sectional Janus structure together, developed a simple spray-and-dry strategy to obtain three types of biomimetic asymmetric meshes, and explored the working modes for atmospheric fog collection. The surface wettability could be carefully controlled, and various asymmetric meshes with different water transportation behaviors were obtained. Through a detailed study of the fog collection process, we concluded that there existed three main working modes: Janus mode, hybrid mode, and Janus and hybrid mode. It was noted that the dual-directional Janus pump with the Janus and hybrid working mode balanced the fog capture and water removal ability and exhibited the highest water collection rate of 2478.73 mg m −2 h −1 , which was 2.61 times more than that of the corresponding superhydrophilic mesh. Furthermore, the prepared dual-directional Janus pump showed superior mechanical durability and antibacterial ability. In general, this work was considered instrumental in the reasonable design of biomimetic asymmetric meshes and could provide references for efficient atmospheric fog harvesting.

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Membrane separation technology is attracting a broad spectrum of attention because of its low energy consumption and superior availability in oily wastewater treatment. Poly(vinylidene fluoride) (PVDF) membranes play an important role in membrane separation field. Herein, a kind of superhydrophilic/underwater superoleophobic nanoparticles modified PVDF membrane based on mussel-inspired chemistry was prepared via a one-pot method. This method applied the Michael addition/Schiff base reactions between dopamine (DA) and alkoxy hydrolysis of (3-Aminopropyl) trimethoxysilane (APTMS). The water contact angle (WCA) decreased from 117∘ to 12.6∘ after the modification. The resultant superhydrophilic/underwater superoleophobic membrane exhibited the outstanding water flux (12280.4[Formula: see text]L m[Formula: see text] h[Formula: see text] bar[Formula: see text], which was a sixfold increment compared to Pristine PVDF. Besides, the resultant membranes showed the effective separation of various oil–water emulsions [Formula: see text], and a high recoverability in multiple-iterations presented the membrane possessing the performance of persistent separation. With the simplicity of one-pot method preparation, outstanding performance, and environmental friendliness, this work provided a potential strategy to large-scale modified membrane materials for the treatment of oily wastewater.