Fog collection using hydrophobic and hydrophilic treatments on wrinkle-based multilayered surfaces

This study evaluated the fog-collection efficiency of wrinkle-based multilayer surfaces using hydrophilic and hydrophobic treatments. The wrinkle structures were fabricated by leveraging the elastic modulus and Poisson's ratio of polydimethylsiloxane (PDMS) and ultraviolet (UV) resin. The optimal wrinkle periodicity for fog collection was determined by varying the spin-coating rate of the UV resin. Chemical surface treatments were examined by applying hydrophilic (hyaluronic acid [HA]) and hydrophobic (perfluoropolyether [PFPE] and TiO₂-PFPE) agents. Surfaces with perpendicular wrinkles treated with TiO₂-PFPE demonstrated the highest fog-collection efficiency due to increased surface roughness that promoted droplet nucleation and growth. These wrinkles further optimized efficiency by facilitating the rapid downward flow of water droplets through the combined effects of gravity and capillary action. The study highlights the significant impact of wrinkle structures and surface treatments on fog collection, with the TiO₂-PFPE treatment showing particular effectiveness and potential for applications in arid regions.