Biomimetic fluorine-free 3D alternating hydrophilic–superhydrophobic surfaces with different bump morphologies for efficient water harvesting

Abstract

Biomimetic 3D hydrophilic–superhydrophobic hybrid surfaces with bump structures were prepared by a combination of spin-coating and high-temperature calcination. How wettability and different bulge morphologies affect droplet capture and removal behavior were compared and analyzed. Hydrophilic–superhydrophobic hybrid PDMS@copper with linear bumps showed the best water-collecting performance, bettering by 151% the original copper sheet and showing a 135% improvement over a superhydrophobic surface without bulges. Both hemispherical and linear bulges accelerate droplet nucleation and growth, but the unique anisotropy of linear bulges enhances the water collection performance of samples with linear bulges. This combination of hybrid wettability and surface morphology inspires 3D structured surfaces and hybrid wettability surfaces.