Preparation And Application Of Superhydrophobic Surface Based On Diffusion Bonding

Superhydrophobic surfaces are widely found in nature,and the non-wetting property of water droplets makes the surface have some special functions,such as anti-corrosion,self-cleaning,anti-fog,anti-icing,etc.Therefore,it has a good application prospect in the engineering field.The key of superhydrophobic surface preparation is the structure of surface micro-nano-structures.The existing preparation methods are limited by cost,accuracy and other problems,which limit the application of superhydrophobic surface in metal materials.In this study,the method of diffusion connection was used to make use of its characteristics of accurate regulation of micron scale.Through chemical corrosion,preparation of nano-structure and modification,the functional super-hydrophobic surface was successfully prepared.The copper foils and the titanium foils were stacked at intervals,and the diffusion connection was carried out under the condition of a connection temperature of 800?and a holding time of 5 min.Flat interfaces were obtained.Corrosion process was carried out by a 3.76 mol/L FeCl₃ solution at 50?,the bottom of the groove after corrosion is flat and the depth is controllable.Rough surfaces with different groove spacing and depth-width ratio were constructed by controlling different corrosion time.After modification with 0.01 mol/L of n-dodecyl alcohol solution for 24 hours,the measurement of the contact angle on the corroded samples showed that the surface of the sample with 60 mum copper foil diffused and corroded has the best hydrophobic property.We did anodic oxidation experiments using 1mol/L NaOH solution as electrolyte.The test piece is placed on the anode,Pt is used as the cathode.A rough surface with TiO₂ and CuO was prepared under the process conditions of current parameter of 3.54A/cm² and oxidation time of 90s.The composite surface has a surface morphology of dense spherical particles of about 300 nm in diameter.After being modified by 0.01 mol/L of n-dodecyl alcohol solution for 24 h,a superhydrophobic surface with a contact angle greater than 160°and a rolling angle of less than 3°was prepared.After testing,the surface bounce phenomenon and self-cleaning function were observed.A rough surface with a depth-width ratio of 1 was obtained by diffusion connection of 60?m wide copper foil and 10?m wide titanium foil.The mixed solution of 1mol/L?NH₄?₂SO₄+0.5wt%NH₄F was used as electrolyte.The specimen was placed in the anode and Pt was used as the cathode for anodic oxidation test.The optimal technological parameters were obtained as current density:150mA/dm²,oxidation time 20s,and the acid-resistant and alkal-resistant surface with silk reticulated TiO₂ nanometer surface morphology was prepared.After 20min exposure to ultraviolet light,the wettability changes significantly,and the surface with light-controlled wettability changes is realized.Functional surfaces with wettability varying with the pH value of droplet were prepared after 24h immersion in 1mmol/L ethanol solution with HS?CH₂?₉CH₃ and HS?CH₂?₁₀COOH molar ratio of 3:2.The prepared functional surfaces have great application prospects in microfluidic control,oil and water separation and other fields.