Simple fabrication of patterned wettability surfaces for efficient fog harvesting
摘要
This study aims to develop a simple, low-cost method for preparing patterned non-uniform wettability surfaces for efficient fog collection. Inspired by the desert beetle Stenocara, a patterned surface consisting of hydrophilic circular regions and hydrophobic channels was designed on a 6061 aluminum substrate. Micro-nanorough structures were formed through chemical etching with a copper chloride solution, followed by selective masking modification using polyimide tape to achieve non-uniform wettability. The surface morphology, chemical composition, and wettability were characterized using scanning electron microscopy, Fourier transform infrared spectroscopy, Raman spectroscopy, and X-ray photoelectron spectroscopy. Fog collection performance was evaluated under a fog flow velocity of 2.0 m/s, a temperature of 25 °C, and relative humidity of 85%, and the effects of the hydrophilic circle diameter and hydrophobic channel width on the collection rate were systematically studied. The optimal preparation process parameters were: etching in 1 mol/L copper chloride solution for 15 s and polyimide tape modification for 25 min. The fabricated surface had a static contact angle of 8.5° in the hydrophilic region and 151.3° in the hydrophobic region. The optimal geometric parameters were a hydrophilic circle diameter of 1.1 mm, hydrophobic channel width of 0.9 mm, and 100 water collection units, at which the maximum fog collection rate reached 3.18 g·h−1·cm−2. The results indicate that the proposed strategy combining chemical etching and mask modification provides a simple, low-cost, and scalable method for preparing patterned non-uniform wettability surfaces with excellent fog collection performance.