Construction Of Durable Superhydrophobic Bionic Coatings And Study On Their Ice Resistance

It has received a lot of attention from researchers.However,superhydrophobic coatings usually have poor wear resistance and stability,and the micro-nano structure on the surface of the coating is easily destroyed in practical application,resulting in serious degradation of superhydrophobic properties.In this study,aiming at the wear resistance and durability problems of superhydrophobic coatings,a nickel nano-cone array material with controllable size was prepared by electrodeposition,and a superhydrophobic coating with armor structure was prepared by laser processing,and the micro-nano structure of the coating was characterized in detail,and the organic relationship between micro-nanostructure and superhydrophobic was established,which provided technical support for the preparation of durable superhydrophobic coatings and their application in the field of anti-icing.The main findings are summarized below:In this study,superhydrophobic nickel nanocone array materials with controllable size were prepared by adjusting the electrodeposition parameters,and their comprehensive properties were evaluated.Firstly,the effects of pretreatment conditions,current density and electrodeposition time on the micromorphology of nickel nanocone were discussed,the morphology,size and distribution of nickel nanocone under different electrodeposition times were studied in detail,the preferred orientation of nickel nanocone coating was analyzed,and the growth mechanism was preliminarily studied,and the results showed that the growth mode of nickel nanocone was stepwise growth driven by spiral dislocation.Then,the superhydrophobic properties of nickel nanocone coating under different electrodeposition times were compared through a series of wetting tests,and the mechanical stability of nickel nanocone coating was verified by self-made friction wear device.It is found that the nickel nanocone has the best superhydrophobic properties and mechanical properties at 25 min of electrodeposition,and the contact angle is still 152° after friction of800 mm under a load of 0.9 k Pa.The newly grown tiny Ni nanocone provides an additional air cushion to support surface water droplets and improve abrasion resistance.Superhydrophobic nickel nanocones have good durability,and nickel nanocones exhibit stable and excellent superhydrophobic properties after one week exposure to atmospheric environment or immersion in 3.5wt% Na Cl solution for 24 h.Finally,the anti-icing performance of the coating was characterized by in-situ ice condensation test,and the mechanism of water droplet icing on the surface of the superhydrophobic coating was studied from the nucleation barrier required for icing and the heat transfer model of the interface between water droplets and coatings.The results show that the superhydrophobic nickel coating has good anti-icing performance,and its anti-icing performance can be increased by 80% compared with SUS304 matrix.The study found that water droplets freeze from the contact point between the water and the sample surface.Surface damage,such as scratches and holes,can reduce the icing resistance of superhydrophobic samples.In order to further improve the wear resistance and durability of superhydrophobic nickel nanocones,this work uses laser processing to design and prepare Laser making(LM)coatings with micron protrusions and groove arrays,and electrodepositions nickel nanocones are electrodeposited on the structure to prepare a strong and wear-resistant Laser making and electrodeposition(LME)coating.Firstly,the microstructure of the coating surface and section was studied in detail by SEM,the presence of air layer in the micro-nano structure was visually proved by contact angle measuring instrument,and the difference of hydrophobicity between LM and LME coatings was analyzed in detail.The results show that the LME coating has excellent superhydrophobic properties,and its contact angle is as high as 172° and the rolling angle is about 0.2°.The use of lift and press water drop tests and water jet reflection behavior proves that the LME coating has very low adhesion to water droplets.Then,through well-designed friction and wear instruments and extensive wear tests(using steel wire ball,sandpaper,tweezer mechanical friction coating),it was proved that the LME coating has excellent wear resistance and stable superhydrophobic properties.The mechanical test results show that the LME coating has a contact angle of up to 170° after a frictional wear of 6000 mm under a load of 0.9 k Pa,and the rolling angle of the coating remains below 5°.Then,mathematical and physical models were established to analyze the wear mechanism of the superhydrophobic coating(LME coating)of the armor structure in depth.Its excellent wear resistance is mainly due to the protection of the needle cone by the micron protrusion and groove array,so that the nano cone on the side wall and bottom can continuously provide a stable air cushion,so the coating still has excellent superhydrophobic properties even after wear.In addition,the good adhesion of the LME coating to the substrate was proved after 50 tape peeling tests,and the saline immersion test for up to 24 h showed the excellent corrosion resistance of the coating.Finally,the in-situ ice freezing test proved that the LME coating has excellent long-term anti-icing performance,compared with SUS304 matrix,its anti-icing performance can be increased by 1.6 times,and the superhydrophobic performance of the coating can remain stable after 5 icing and ice melting cycles,and the wettability test results show that its contact angle is continuously stable above 160°.