Biomimetic Ventilation Cap Structure Enables Passive Water Collection and Stable Power Generation

This study aimed to address the global challenges of freshwater scarcity and energy shortage by developing a bioinspired and multifunctional fog collector. Drawing inspiration from the architecture of unpowered ventilation caps and the surface structure of desert beetles, the researchers engineered a three-dimensional device featuring a wettability gradient. This advanced structure featured a 360° array of blades composed of superhydrophobic surfaces and superhydrophilic regions, enabling omnidirectional fog collection while simultaneously utilizing rotational motion to generate electricity. Experimental evaluations demonstrated that the device achieved a fog collection efficiency of 7620 mg cm^-2 h^-1 under conditions of 2.6 m/s wind speed and 100% relative humidity. Additionally, the system generated a stable electrical output of 0.6 V and 5 mA at a wind speed of 7 mph. The fabrication process involved laser scanning and chemical modification to establish superhydrophobic and superhydrophilic regions, thereby creating a wettability gradient. This configuration, in conjunction with centrifugal forces, facilitated the effective capture and directed transport of water droplets. The device also exhibited robust durability across repeated experimental trials, underscoring its suitability for prolonged use. This work presented a novel design paradigm for fog collection systems and offered promising applications in mitigating both water and energy scarcity.