Effect of graphene oxide and fluorinated polymeric chains incorporated in a multilayered sol-gel nanocoating for the design of corrosion resistant and hydrophobic surfaces

In this work, it is proposed a multilayer sol-gel nanocoating onto aluminum alloys for the fabrication of new surfaces with a dual property of hydrophobicity and corrosion resistance. A study of two experimental variables such as number of dips and thermal treatment has been performed in order to have a better optimization of the nanocoatings with the desired corrosion resistance properties. A combination of a hybrid sol-gel matrix to host the corrosion inhibitor (graphene oxide) with a simple sol-gel matrix to provide hydrophobic properties (fluorinated polymeric chains) is presented. The effect of the thermal treatment is also analyzed for the formation of highly cross-linked sol-gel matrices with an improvement in the mechanical and hydrophobic properties. The surface and coating morphology have been determined by using atomic force microscopy, profilometry and scanning electron microscopy; whereas the hydrophobicity was determined by measurements of the water contact angle. Finally, the corrosion resistance of the sol-gel coatings has been determined using potentiodynamic polarization and electrochemical impedance spectroscopy. These results open up a new perspective for the design and implementation of novel coatings in applications of high performance.