From Solution to Microstructures in Minutes: Microdroplet-Derived Stand-Alone TiO<sub>2</sub> Surfaces for Simultaneous Water Harvesting and Treatment
Keerthana Unni, Jenifer Shantha Kumar, Anirban Som, Depanjan Sarkar, Thalappil Pradeep
Abstract
We present a straightforward and eco-friendly method to transform a titanium tetraisopropoxide (TTIP) solution into superhydrophobic TiO 2 microstructures by ambient microdroplet deposition. At lower temperatures the micropillars of amorphous TiO 2 act as nucleation sites for condensing humidity to form droplets. However, the microstructures facilitate efficient water runoff despite TiO 2 ’s hydrophilic character by a combination of surface hydrophobicity and gravity. Additionally, the photocatalytic TiO 2 surface resists biofilm formation and degrades the contaminants, offering long-term collection of safe water and its purification, which has been demonstrated with examples. We demonstrate that the microdroplet-based methodology developed for the conversion of solution into microdroplets can also be applied to other metal oxides, including CuO and ZnO, highlighting the universality of the process.