Fabrication Of Colorful Superhydrophobic Surfaces On Al Substrates

The surface, which the contact angle is greater than 150° and sliding angle of less than 10°, is called super-hydrophobic surfaces. In recent years, the researcher had prepared the super-hydrophobic surface in the aluminum matrix with method of electricity etching, chemical etching and so on. It is desirable to obtain both the super-hydrophobic surface with self-cleaning and decorative beauty property in the life application. Therefore, the preparation of color super-hydrophobic surface has a great application value in life decoration, meanwhile, in urban construction, environmental protection and energy saving and other fields has research significance potentially.The obtain method of color super-hydrophobic surface includes brush plating, electrochemical deposition, spraying, and so on. However, the obtained surface color of brush plating is limited, while electrochemical deposition and spraying are difficult in obtaining multi-color surface.To solve these problems, based on the analysis of the theory of wettability and research status of metal matrix coloring, a series of experiment are carried out in establishment Nano microstructure and hole sealing and coloring in metal materials. The main research work and results are as follows.The aluminum matrix after electrochemically etched is electrolytic colored in mixed solution of potassium permanganate and sulfuric acid (0.07 mol/L H2SO4,0.0095 mol/L KMnO4,0.0495 mol/L Al2O3) and modified with fluoroalkyl silanes to reduce surface energy, then the golden aluminum super-hydrophobic surface will be obtained. The microstructure of specimen surface, chemical ingredient and wettability were characterized in the optimum process parameters of colored time of 3 min and coloring voltage of 10V. The results showed that the contact angle of water droplet and surface reaches 159.3° and rolling angle is 1°.The oxidized aluminum matrix anode after electrochemically etched is electrolytic colored in mixed solution (0.05 mol/L H2SO4,0.0495 mol/L A12O3,0.04 mol/L NiSO4·6H2O, 0.038 mol/L CuSO4·5H2O,0.067 mol/(NH4) 2SO4) and modified with fluoroalkyl silanes to reduce surface energy, then the black aluminum super-hydrophobic surface will be obtained. The good hydrophobic nature is obtained in the optimum process parameters of colored time of 30 min and coloring voltage of 14V, and the contact angle of water droplet and surface reaches 158.3° and rolling angle is 1°.This paper focuses on the effect of electrolytic coloring voltage and time on color and wettability of golden surface. It is found that the coloring voltage and time are key factors to effect specimen surface color, while has less effect on surface wettability. The yellowish-brown super-hydrophobic surface with bright color and good super hydrophobic property (contact angle of 157.2° and roll angle of 1°) can be obtained in the condition of coloring voltage of 10 V and coloring time of 3 min.The copper solution and stearate solution can be obtained when the copper and stearate added into anhydrous ethanol respectively and stir fully. The stearic acid copper slurry can be obtained after stir these two solution, and the slurry after many times filtered wash soluble in anhydrous ethanol will get good hydrophobic property, which contact angle of water droplet and surface is 168.3° and roll angle isl°.The obtained super-hydrophobic surface with above method has good color and wettability stability, which has potential applications value in urban beautification, life decoration, and other fields.