Preparation Of Multifunctional Super-wetting Surface And Research On Surface And Interface Behavior

Superlyophobic surface refers to a kind of surface with excellent sliding effect to liquids,usually including superhydrophobic surface,superoleophobic surface,and slippery surface,etc.Due to the excellent liquid repellent effect,these surfaces have exciting performances in many fields such as anti-fouling,self-cleaning,pipeline transportation,medical treatment,military and so on.In recent years,with the deepening of research,the preparation methods of superlyophobic coatings have become more abundant,such as microarrays,laser processing,photolithography and templating methods.Despite the advantages of these methods in their application environments,there are some limitations to overcome.Based on the in-depth study of relevant literature,this paper reported that a series of superlyophobic surfaces with different properties and functions,including superoleophobic surface,water-repellent surface,and oil-repllent surface,were prepared via the sol-gel method,covalent grafting method and spraying method based on the design principle of superlyophobic surface.We systematically studied the relevant superlyophobic mechanism,and carried out related tests on its anti-fouling performance,mechanical stability and anti-corrosion performance.Specifically:(1)Through the condensation condensation of 1H,1H,2H,2H-perfluorooctyltrichlorosilane(PFOTS)and Tetraethylorthosilicate(TEOS)to modify fumed Si O₂ nanoparticles,and then the solution was sprayed and dried to obtain a transparent superoleophobic coating.The contact angle(CA)of the coating to water and hexadecane both exceed 150°,the sliding angle(SA)of water is2±0.5°,and the SA of hexadecane is 8.4±0.5°.The coating is highly transparent and its transmittance in the visible wavelength range exceeds 82.3%.Besides,the coating shows excellent thermal stability,mechanical stability,chemical stability and self-cleaning ability.It is heat treated at 300?for 2 h,polluted by corrosive liquids,and impacted from a 30cm height of sand,the coating maintains outstanding liquid repellency.(2)Due to the rough structure of the superhydrophobic coating susceptible to damage to affect the liquid-repellent performance,utilizing epoxy resin/amine reaction to modify the epoxy resin with monoglycidyl ether-terminated polydimethylsiloxane(PDMS^ME)and polyamidoamine(PAMAM),then sprayed to obtain a transparent hydrophobic slippery coating.The grafted PDMS brush provides low surface energy and acts as a liquid phase to eliminate the barrier of droplet slip.Therefore,the SA of the coating is extremely low(<5°),and the sliding speed reaches 1.16 mm/s.The coating exhibits an outstanding anti-fouling effect,and the SA to liquids such as water,mud,ink and juice are less than 15°.The coating has excellent corrosion resistance,and the corrosion current density is reduced by 6 orders of magnitude compared with the original steel sheet.Besides,the coating has excellent thermal stability and physical and chemical stability.The SA of coating is less than 10°after the thumb press,knife scratching.The coating remains prominent sliding property after heat treatment at 120°C for 100 h.(3)Aiming at the problem that the liquid repellency of coating cannot be restored after entirely destruction,PDMS^ME was grafted onto PAMAM via epoxy resin/amine reaction under oil bath to prepare a copolymer,which was mixed with polytetrafluorowax(PFW)and commercial epoxy resin formula in proportion,then sprayed and heated to obtain self-repairing oleophobic slippey coating.The coating shows good sliding performance for a variety of low surface energy liquids.The SA of hexadecane is 8.3±0.7°,and the SA of ethanol is 6.4±0.7°.Due to the lubrication effect of PMDS brushes and the anti-friction property of PFW,the friction coefficient curve of coating remains stable under the long-term friction with a load of 3 N.PFW heated at high temperature will melt to liquid state and then replenish the destroyed surface thus achieving a self-repairing effect.After four damage-repair cycles,the coating still exhibits excellent mechanical stability.The corrosion resistance of the coating is further improved,and corrosion current density is reduced by 8 orders of magnitude compared with the original steel sheet.The coating is sprayed to cover common wooden surfaces,ceramic tiles and steel sheets and still has sliding property and self-repairing ability,indicating that the coating has a wide range of application prospects.