Fabrication Of Super-hydrophobic Surfaces On Metallic Substrates And Research On Anti-corrosion And Anti-biofilm Properties

The ocean epoch is coming, the marine materials and the technic of surface protection are urgent needed in the area of exploitation of marine resources, transport in ocean and marine engineering. Because of interesting properties and important applications in fundamental researches and industrial applications, super-hydrophobic surface has attracted significant attention, and various fabrication methods have been reported. However, to the best of our knowledge, little attention has been paid to super-hydrophobic surface equipped with anticorrosion properties to metallic surface. Such surface is of great importance for many industrial applications, and may present a solution to the long-standing problems of environmental contamination and corrosion of metals and metal alloysA novel super-hydrophobic film was prepared by myristic acid (n-tetradecanoic) chemically adsorbed onto the copper wafer. The film formation and its structure were characterized by means of water contact angle measurement, Fourier transformation infrared spectroscopy (FTIR) and scanning electron microscopy (SEM). The static contact angle for water on the surface of this organic film was measured to be as high as 158·.The formation of a composite interface composed of the flower-like surface nanostructures, water droplet and air trapped in the crevices was suggested to be responsible for the superior water-repellent property. The corrosion behavior of the super-hydrophobic surface was investigated with potentiodynamic polarization measurements and electrochemical impedance spectroscopy. Due to the'air valleys'and'capillarity'effects, the corrosion resistance of the material was improved remarkably.A novel and stable super-hydrophobic film was prepared by myristic acid (CH₃(CH₂)₁₂COOH, mya) chemically adsorbed onto the anodized aluminum surface. The static contact angle for seawater on the surface was measured to be 154o. As evidenced by molecular dynamics (MD) simulations and electrochemical impedance spectroscopy (EIS), the effect of ethanol solvent on the film stability was proved. The surface structure and composition were then characterized by means of scanning electron microscopy (SEM) with energy dispersive X-ray spectrum (EDS) and atomic force microscope (AFM). The electrochemical measurements showed that the super-hydrophobic surface significantly decreased the corrosion currents densities (icorr), corrosion rates and double layer capacitance (Cdl), as simultaneously increased the values of polarization resistance (Rct) of aluminum in sterile seawater.A super-hydrophobic film was prepared by myristic acid (CH₃(CH₂)₁₂COOH chemically adsorbed onto the polyethyleneimine (PEI) coated Fe₃Al-type intermetallic wafer. The film character and structure were probed with contact angle measurement, scanning electron microscopy (SEM) and atomic force microscope (AFM). The results suggested that the structure of the film is similar to lotus and the seawater contact angle was larger than 150·. Moreover, the corrosion resistances of untreated and modified samples in seawater were investigated by electrochemical impedance spectroscopy (EIS). Experimental results showed that the corrosion rate of Fe3Al-type intermetallic with super-hydrophobic surface decreases dramatically because of its special microstructure.In addition, the preponderant bacterium was obtained from the surfaces of copper, aluminum and Fe3Al-type intermetallic which were staticly hung in natural sea water from Qingdao for different times. The preponderant bacterium was identified as Vibrio natriegens (V. natriegens) through biological method namely PCR. The survival habit and growth curve were studied using nephelometery. Moreover, the effect on microbial attachment of superhydrophobic surface was discussed using fluorescence microscope.