Load-responsive bionic kirigami structures for high-efficient fog harvesting

Harvesting fog is a charming approach to alleviating the global water shortage crisis. However, it is extremely challenging to design fog collectors with high efficiency due to the scarce geometric driving structures. Herein, we develop a 3D kirigami structure inspired by the new corrugated driving structures in the Bird's Nest Fern, which can be fabricated by simple shearing and stretching. Its water collection ratio increases with the external load, forming the unique load responsiveness. The kirigami structure owns a 3D array configuration to enhance flow velocity for the efficient droplet condensation rate and has geometric and wetting gradients to transport condensate droplets spontaneously and quickly, contributing to a high water collection efficiency. The water collection ratio can reach 3.45 times that of a pure iron sheet by only changing the geometric structure, and the highest ratio can even reach 4.58 times with the assistance of wetting gradients.