The Study On Micro/Nano Structure Construction And Stability Of Biomimetic Slippery Lubricant-infused Surface

As an important metal material in human life and production,copper and its alloys have a wide range of applications in industry and agriculture,daily life and new industrial fields.However,copper is susceptible to environmental factors such as temperature,humidity and p H during use,and when subjected to corrosion it can extend from the surface to the substrate,thus losing its effectiveness.Superhydrophobic surfaces,on the other hand,are expected to improve their stability because of their corrosion resistance.Inspired by lotus leaves,superhydrophobic surfaces with a solid/gas composite structure can be obtained by constructing micro/nano rough structures and after modification with low surface energy substances.However,as the pressure-bearing capacity and stability of the gas film captured by the superhydrophobic surface are limited,inspired by pigweed,a slippery lubricant-infused surface is prepared by injecting a low surface energy liquid into the porous rough structure and constructing a continuous and stable solid/liquid composite film layer through capillary action.Based on the research of related literature,this thesis carries out a systematic research work on the preparation,stability and application of bionic superhydrophobic surfaces and biomimetic slippery lubricant-infused surface.The main content is divided into two areas as follows:A mixture of sodium hydroxide and ammonium persulphate was chosen as the oxidising agent and copper hydroxide micro/nano structures with different microscopic morphologies（needle-like and petal-like）were constructed by chemical etching.Superhydrophobic copper oxide surfaces were obtained after heat treatment and modification with fluorine-free octadecanethiol/ethanol solutions.The superhydrophobic surfaces with optimum hydrophobicity were obtained by comparing the effect of different etching times and modification times on the morphology of the copper oxide micro/nano films.On this basis,the surface was injected with lubricating oil,at which point there was a capillary interaction between the substrate micro-nano structure and the infused dimethyl silicone oil,transforming the superhydrophobic surface into a stable super-slip surface.This oil-injected surface has good physical and chemical stability,and can maintain its hydrophobic properties after knife scraping,strong shear forces of 1000-7000 rmp and strong acids and bases in harsh environments.It also has excellent performance in corrosion resistance and self-cleaning tests.The original SiO₂ nanoparticles were modified with cetyltrimethoxysilane（HDTMS）and a silane coupling agent（KH-570）based on SiO₂ nanoparticles.The modified SiO₂ particles have low surface energy and reduce the agglomeration phenomenon of the particles.Inorganic aluminium phosphate is used as the binder and the modified particles are mixed with inorganic aluminium phosphate in a certain ratio and sprayed onto the cleaned copper sheets with a spray gun.After curing a superhydrophobic coating is obtained and finally a stable SiO₂ slippery coating will be obtained after injection of silicone oil.The surface has a stable sliding angle（10°）even after knife etching tests,different shear forces,acid and alkaline solutions,long-term storage and high temperature treatment,and the contact angle remains stable at around 100°.In addition,the superhydrophobic and slippery coated surfaces can regain their wetting characteristics after immersion in salt solutions by a simple repair process.Moreover,the SiO₂superhydrophobic and slippery coatings remain stable and have excellent corrosion resistance compared to the original copper sheet.This stable surface/interface can therefore be applied for condensation of liquid droplets in humid environments.Under high humidity conditions,the slippery coating has a high mist water collection efficiency.