A conical shaped self-healing slippery film for enhanced fog harvesting in windy environment

Abstract

Wind presents both advantages and disadvantages for water collection. It can bring an abundant fog resource to arid areas for water harvesting, however, some of the captured water droplets are inevitably blown away in a windy environment because of the easy-sliding property of the material surface. Herein, a conical-shaped, self-healing, liquid-infused film with tunable cone angles based on candle soot, thermoplastic poly (ethylene-co-vinyl acetate) (EVA), and hydrophobic silicone oil has been developed using a simple template method and traditional Chinese origami. Benefiting from the inward force induced by the conical structure, the condensed droplets prefer to gather toward the top of the conical structure in windy environments rather than splashing out, which usually occurs on a plane surface. This advantage can greatly ensure the high water collection efficiency of materials in windy regions. In addition, owing to the unique photothermal property and thermoplasticity of the designed conical structure, surface scratches during application can be quickly repaired under solar illumination without extra fossil energy consumption, and long-term stable application of the materials can be guaranteed. Therefore, this study finely synergized structure design and performance enhancement and established a new paradigm for effective and reliable fog harvesting applications.