Study On Preparation And Performance Of Fog Harvesting Materials Based On Biomimetic Slippery Lubricant-Infused Surface

Fresh water accounts for only a small fraction of the world’s water resources.Recently,as the economy and population have grown,the deficiency of fresh water is getting progressively worse.Inspired by creatures in nature(Namib desert beetles,cacti,spider silk and pitcher palnts,etc.),a range of fog harvesting materials has been prepared.Due to its excellent sliding capacity,the slippery lubricant-infused surface is applied to fog harvesting.Unfortunately,as the period of sevice time extended,the lubricant film on the surface will gradually become thin and disappear eventually,leading to the failure of the surface.Therefore,it is vital to improve the physical durability and chemical stability of lubricant-infused surface.Based on previous literature research,this work prepared a lubricant-infused surface with brilliant mechanical durability and chemical stability and designed a simple fabrication approach of lubricantinfused surface on the premise of ensuring the performance.The research content is mainly divided into the following two aspects:(1)Inspired by pitcher plants,the nanotree array covered frame was prepared by electrochemical and hydrothermal methods using copper foam as the base material.The main stem of the nanotree was composed of Cu O nanorods,and the branches were composed of Zn O nanorods.Then,dimethylsilane is infused into Zn O nanorods under ultraviolet irradiation.During this process,poly(dimethylsilane)is grafted onto Zn O nanorods,forming a layer of superhydrophobc molecular brush on the surface.The excess poly(dimethylsilane)not grafted onto Zn O nanorods acts as a lubricant,and finally a slippery lubricant-infused surface was obtained.Due to the nanotree array structure and the existence of Zn-O-Si covalent bond between polydimethylsiloxane and zinc oxide nanorods,the substrate exhibited excellent lubricant locking ability,and can still maintain good performance after a series of physical and chemical stability tests.Moreover,the fog harvesting efficiency is higher than the original copper foam.(2)The dynamic bubble template method was used to prepare porous foam-like micro/nanostructure on the surface of the copper sheet,and the pore wall was composed of closely interlaced needle-like nano-branches.After modification by perfluorodecyl mercaptan,the surface was transferred into a superhydrophobic surface,which was then injected with perfluoropolyethers as a lubricant.The surface exhibits good sliding property and low sliding angle for many organic solvents.At the same time,the surface also shows excellent physical and chemical stability.After ultraviolet illumination,shear resistance test,acid-base solution corrosion test and long-term storage test,it still shows brilliant droplet sliding performance.More importantly,compared with other lubricant-infused surfaces,our approach is simpler and less time-consuming,and a range of properties of the lubricant-infused surface are not affected by the simplification of the preparation method.