Durable Lubricant-Impregnated Surfaces for Water Collection under Extremely Severe Working Conditions.

Abstract

It is worth noting that the multifunctional surfaces are highly desirable for water collection applications on droplet nucleation and removal. Although the superhydrophobic surfaces is beneficial to water collection due to easily shed liquid drops and favorable heat-transfer performance, the pinned condensed water droplets within the rough structure and a high thermodynamic energy barrier for nucleation severely limit the water collection efficiency. Recently, the liquid-infused surfaces have been significant for condensation heat transfer and droplet nucleation but have poor durability. In this work, under the UV light, polydimethylsiloxane was grafted onto ZnO nanorods (through Zn-O-Si bond), and the residual unbonded silicone oil was used as the lubricant, so that it form a hierarchical lubricant-impregnated surfaces. Because of high viscosity of silicone oil and strong intermolecular force between silicone oil and PDMS brush, the lubricant can be firmly fixed in micronanostructure to form a durable lubricant layer. For example, the LISs have outstanding properties such as boiling water repellency, omniphobicity of various liquid, and hot water resistance. Under a self-made hot vapor collection device, the surface can maintain good water collection capacity and there is no obvious change in the lubrication layer. After exposing in sunlight for 7 days and subjecting them to 25 times heating/cooling cycles (heating at 150 °C), the LISs exhibit excellent water collection and repairability. After measurement, the oil content in the water is 43 mg/L, which is harmless to the human body. Through the high-water collection efficiency and durable lubricant layer, the LISs can be applied on a large scale in the water collection industry.