Fog harvesting is an important method to solve the water shortage in arid and semi-arid areas by collecting water from air. Improving fog harvesting efficiency is still a big challenge to be overcome. Herein, under the inspiration of natural creatures, a novel harvesting structure that couples a hierarchical microchannel (HMC) needle with the Janus membrane by taking a conical pore as their junction is proposed. Such an HMC-conical pore-Janus membrane system can improve the harvesting efficiency by regulation of liquid behavior in the whole fog harvesting process involving droplet capture from air, high speed transport on the microchannel, and droplet detachment from Janus. The synergistic effects of the hierarchical channel-conical pore-Janus structure are exploited in terms of capture, transport, and detachment capabilities, and their underlying mechanism to enhance fog harvesting efficiency is built. Compared with the traditional harvesting structure, the proposed hierarchical channel-conical-Janus coupling mode was demonstrated to improve fog harvesting efficiency by 90%. Such a coupled system has potential applications in efficient fog harvesting systems, microfluidic devices, and liquid manipulation.

normally tend to condense on the protruding solid surface, but the already condensed bulked water film will slow down further condensation. [6][7][8] In nature, many biological samples have developed unique parts to solve the bulked water film-restrained fog condensation, [9][10][11] such as spider silk with spindle-knots [12][13][14] and cactus with cone spines. [15][16][17] Their conical structures can directionally transport condensed water from the tip to the bottom, releasing the tip surface area for further fog condensation. [18][19][20][21][22] Conical structures are usually combined with fog harps to construct fog collectors for highly efficient fog harvesting. [23][24][25][26][27][28] However, the velocity of directional water transport on these conical structures remains of ≈0.5 mm s −1 , which limits further enhancement of fog harvesting by fog collectors.Fortunately, a more efficient fog harvesting and transport mode was discovered on Sarracenia trichomes that has a unique hierarchical microchannel structure around the needle-shaped trichomes (Figure 1a). [29] A thin water film is automatically formed on the hierarchical microchannel structure to generate superslippery capillaries, which remarkably enhances the water transport capability and further reinforces the fog harvesting efficiency of trichomes. The hierarchical microchannel shows greater properties than the uniform microchannel, which can also aid on the development of new microfluidic systems. [30][31][32][33] However, the underlying dynamic mechanism of hierarchical microchannel-induced ultrafast transport on fog harvesting is still ambiguous, and the multiscale structural coupling effect on fog harvesting performance is also a great challenge.Herein, we propose an effective strategy to fabricate a bionic Sarracenia trichome (BST) using a one-step thermoplastic stretching approach on a glass fiber bundle under the constraint of an inner gear pattern. The BST possesses an ondemand hierarchical microchannel structure, whose major channels are confined by an inner gear pattern, as well as junior microchannels are automatically assembled by the glass fiber monofilaments. Its excellent gravity-ignoring fog harvesting property was herein demonstrated, which was governed by a superslippery sliding mode, similar to the real Sarracenia trichome. The capillary condensation and fog harvesting theoretical model of BST was built to further discuss the dynamic Fog harvesting through bionic strategies to solve water shortage has drawn considerable attention. Recently, an ultrafast fog harvesting and transport mode was identified in Sarracenia trichome, which is mainly attributed to its superslippery capillary force induced by its unique hierarchical microchannel. However, the underlying effect of hierarchical microchannel-induced ultrafast transport on fog harvesting and the multiscale structural coupling effect on highly efficient fog harvesting are still great challenges. Herein, a bionic Sarracenia trichome (BST) with an on-demand regular hierarchical ...

In article 2100087 , Huawei Chen and co‐workers design a bionic Sarracenia trichome with an on‐demand regular hierarchical microchannel to achieve excellent fog harvesting and transport properties. With the combination of a Janus membrane, a highly efficient multiscale fog collector is developed, in which a gradient high‐pressure field is purposely formed to improve, by threefold, fog harvesting performance compared with a single‐scale structure.