Investigation of Fog Harvesting Performance of Functional Thin Film-Coated 3D Surfaces

Access to clean water is one of the major global challenges due to the depletion of natural freshwater reserves, exacerbated by global warming and increasing world population. Reverse osmosis and desalination methods are commonly used for clean water production; however, these methods have high investment and energy costs, limiting their widespread application. In recent years, atmospheric water collection, using fog, has emerged as an energy-efficient, low-cost, and environmentally friendly alternative method. However, traditional fog harvesting nets have low efficiency, prompting increasing interest in developing materials that can collect fog at higher yields. In this study, 3D printing was used to create surfaces with various topographies, which were then coated with hydrophilic polyacrylic acid (PAA) and hydrophobic polyhexafluorobutyl acrylate (PHFBA) thin films in a single step, utilizing the environmentally friendly plasma enhanced chemical vapor deposition (PECVD) technique. Additionally, surfaces exhibiting both hydrophilic and hydrophobic properties were designed and fabricated. The chemical structure, topographical features, and wettability characteristics of the coated surfaces were thoroughly characterized. A total of 22 samples with different surface structures and wettability properties were produced. Fog harvesting experiments revealed that, compared to the control surface, the surface designs achieved up to a 270% increase in fog harvesting efficiency. The results demonstrate that surface topography and wettability are key factors influencing fog harvesting performance.