Design and construction of a Laplace and wettability gradient field for efficient water collection.

A hydrophilic-hydrophobic hybrid surface with a vein-like pattern was prepared on a copper substrate using 3D printing technology and laser scanning technology. Under the action of the Laplace pressure gradient and wettability gradient, the superhydrophilic (SHL) vein-like pattern on the superhydrophobic (SHB) surface aided the directional transport of water droplets. The presented scheme combined with the wettability and surface pattern could achieve a water-collection efficiency of 4258.59 mg cm h.