Construction Of Superhydrophobic/Superslippery Layer On Construction Steel Surface And Its Anti-Icing Performance

Steel is an indispensable engineering material in the construction field.In recent years,steel structure buildings have received extensive attention due to their advantages of short construction period,low comprehensive cost,green environmental protection,sustainable utilization,and convenient use.However,since steel is a hydrophilic surface,ice is easy to condense on the metal surface in the low temperature environment in winter,which not only increases the load of the metal structure,but also increases the risk of corrosion of the metal,causing serious safety hazards.Therefore,it is of great practical significance to alleviate or solve the formation of ice on the metal surface.With the development of nanotechnology and biomimetic technology,superhydrophobic surface（SHS）has been proposed as a passive anti-icing technology and applied to the field of surface frosting and icing.The superhydrophobic surface can isolate the matrix from the external liquid through a low surface energy film and trapped"air cushion",reduce the contact area between the surface and the droplet/ice,thereby prolonging the nucleation and freezing time of the droplet and reducing the ice adhesion strength.However,the icing protection barrier of the superhydrophobic coating is not permanent.At low temperature and high humidity,non-wettability is lost and the anti-icing properties of the surface fails,and the mechanical durability of superhydrophobic coatings is poor.Therefore,it is crucial to improve the durability of superhydrophobic coatings.Slippery liquid-infused porous surfaces（SLIPS）have received extensive attention due to their excellent liquid repellency,antifouling,anti-icing,self-healing,bacteriostatic and corrosion resistance,and have gradually become a potential alternative to anti-icing superhydrophobic surfaces.Compared with the superhydrophobic surface,the superslippery surface exhibits the stability and high humidity durability of the lubricating film layer under high droplet impact pressure.Based on the research status of surface icing protection all over the world,this paper combines the superhydrophobic and superslippery surface,the two anti-icing coatings to develop a new type of temperature-sensitive superslippery coating,which maximizes the anti-icing performance of the coating,prolonging the freezing time of surface droplets and reducing the ice adhesion strength to the surface.The main conclusions of this study are as follows:（1）The superhydrophobic coatings that are widely applicable to metal surfaces have been prepared.In this experiment,the Zn-Ni alloy coating was first constructed by electrodeposition technology,and then the Zn-Al layered double metal hydroxide was prepared by hydrothermal method.Then,the effects of different hydrothermal reaction temperature,time,and Al（NO₃）₃/Na₂CO₃ concentration ratio on the microstructure and wettability of the superhydrophobic surface were investigated by orthogonal experiments with three factors and three levels.The results showed that when the hydrothermal reaction was carried out at 100°C for 7 hours and the concentration ratio of aluminum nitrate/sodium carbonate was 1:3,the surface morphology presented a uniformly distributed micro-nano"rose"-like structure.The resulting superhydrophobic surface showed a water contact angle as high as 160°and a rolling angle as low as 3°.（2）The prepared superhydrophobic surface shows excellent self-cleaning performance and chemical stability.More importantly,the superhydrophobic surface can significantly delayed the ice formation time at-10°C,which was about 17 times than that of ordinary steel surface.The ice adhesion strength was as low as 3 k Pa,which demonstrated significant anti-icing performance.（3）Fe₃O₄ nanoparticles were uniformly dispersed in the molten paraffin,and then Fe₃O₄/paraffin lubricant was poured into the rough superhydrophobic surface to obtain a stable temperature-sensitive solid superslippery coating.The prepared super-lubricated surface has excellent anti-icing performance,and the icing time can be extended to 1115s at-14°C.The surface ice adhesion strength has good stability during the icing/deicing cycle at-18°C.（4）The temperature-sensitive solid SLIPS can alleviate the loss of liquid lubricating oil,and displayed self-healing property under photothermal action.Moreover,it can resist certain physical damage.Fe₃O₄ nanoparticles endowed the smooth solid surface with the characteristics of remote photothermal deicing,and the higher the content of Fe₃O₄ nanoparticles,the faster the heating rate（5）The superhydrophobic coating and temperature-sensitive solid superslippery coating prepared in this work can not only reduce the icing risk of metal structure,but also provide some reference for metal corrosion protection.