Sustainable Superhydrophobic Surface with Tunable Nanoscale Hydrophilicity for Water Harvesting Applications

Superwettable surfaces show great potential in water harvesting applications, however, a scalable water harvesting surface remains elusive due to the trade-off between water deposition and transport. Herein, we report a unique superhydrophobic surface with tunable nanoscale hydrophilicity constructed by structured Pickering emulsions. Preferential exposure of the cellulose nanocrystal's outer surface and wax microspheres accelerates droplet deposition allowing for the manipulation of droplet mobility. Appropriate tuning of the wetting characteristics of the surfaces, optimizing the hydrophobicity and density of the water affinity nanodomains enhance the water deposition rate without the sacrifice of water transport rate, achieving an optimal water harvesting flux of 3.402 L m^-2  h^-1 for a plate and 5.02 L m^-2  h^-1 for a mesh. This hydrophilic/superhydrophobic surface allows the controllable manipulation of droplet nucleation and removal to enhance the water harvesting efficiency.