An integrative bioinspired venation network with ultra-contrasting wettability for large-scale strongly self-driven and efficient water collection

Collection of water from the atmosphere is a potential route to alleviate the global water shortage. However, it is still difficult to find a strategy to collect sufficient water on a large surface and transport it all off the surface without additional energy input. Inspired by redbud leaves, herein, we proposed a new water-collecting configuration. This configuration utilizes an ultra-contrasting wettability venation network with hierarchical micro-nano structures as the skeleton and integrates the strategies evolved by cacti and beetles. This venation network was fabricated by the technology based on ultra-fast lasers. We achieved a near-unity efficiency in collecting and centralizing the condensed water on the entire surface with a large area. Remarkable water collection and centralization capability were obtained. The venation networks manifested the notable enhancements of approximate to 166%, approximate to 352% and approximate to 644% in water collection efficiency when compared with conventional superhydrophobic surfaces at the tilt angles of 90 degrees, 60 degrees and 30 degrees, respectively. This configuration can work continuously at all tilt angles, even against gravity at a negative tilt angle of 90 degrees. In addition, the venation network can maintain excellent water collecting capability even under very arid conditions. The principle and fabrication technology of this venation network make it possible to scale up a practical network device for mass water collection and may be useful for water desalination, heat transfer, microfluidics, lab-on-a-chip, distillation and many other applications.