The intrigue of directional water collection interface: mechanisms and strategies

Abstract

The shortage of fresh water resources is becoming more and more serious with the acceleration of modernization and industrialization, especially in some dry welding and underdeveloped areas. Scientists are bent on alleviating the issue of fresh water shortage. Concurrently, many biological species have developed elegant schemes for water-harvesting for their survival. Combining their mechanisms and design strategies is crucial to fabricate interfacial materials with efficient water collection. This paper extracts the water-collecting principles and characteristics of Namib Desert beetles, cactus and spider silk, and reviews the synthesis strategies of various bionic water collecting materials under the guidance of these typical creatures. We put an extreme emphasis on the liquid–solid interfacial interaction between the accumulative nuclear dew and functional materials' surfaces. The key factor for reliable water collection materials is the design of robust hierarchical configuration. However, these constructed microstructures are vulnerable and many practical applications are limited. Therefore, the design of architectures with durability has become a serious topic and we highlight the development, current research status on the durability and self-repair of directional water collection materials. Finally, a holistic view and future prospects of bionic directional water collection materials, including mechanisms, characterization, design strategies and fabrication techniques, are provided. We envision that these well-chosen facts and opinions will be useful in fluid handling and transportation, self-cleaning and water collection fields.