Superhydrophobic carbon nanotube/silicon carbide nanowire nanocomposites

a r t i c l e i n f o The composite film of carbon nanotubes and silicon carbide nanowires was synthesized directly on the silicon substrate by the catalyst-assisted method. The carbon nanotubes crimped together decorated with silicon carbide nanowires covering the whole substrate. The appropriate amount of aluminum powders is a crucial factor to achieve the composite film. The composite film exhibited excellent intrinsic superhydrophobicity without any further functionalization. By using the nano/micropillar composite structure model, the presence of silicon carbide nanowires is found to be the key factor that results in the superhydrophobicity of the films. The feasible synthesis of the superhydrophobic coating could have potential application in water-repelling devices, like biochemical sensors and microfluidic systems. The superhydrophobic surface of lotus leaves with a micro/nano-scale hierarchical surface structure has attracted a lot of scientists' interest [1–4], because the superhydrophobicity has a large application potential in opto-electronics, biochemical sensors, and microfluidic systems. In order to meet the requirement in a wide range of application , from window glass and cement to textiles, the demand for the surface is not only superhydrophobicity but also self-cleaning property [5]. Self-cleaning property means that the surface is superhydrophobic and the droplets can be easily removed by slightly tilting the surface to take the dirt away [2]. As a commercial product, the rapidly developed technology of self-cleaning coatings has been divided into two categories: chemical functional surface [6] and artificial superhydrophobic surface [7,8], both of which can increase the hydrophobicity of the coating. High surface roughness can increase the amount of air-trapping pores [9], while chemical coating lowers the free energy [10]. One-dimensional nanomaterials with high surface area and unique morphology make them particular appealing for fabrication of self-cleaning coating applications with high efficiency [11–13]. The unique morphology of one-dimensional nanomaterials enhances the roughness of the surface and increases the amount of the air-trapping pores. As have been demonstrated previously, the surface coated with 1D nano-structure e.g. aligned nanotubes [14], nanofibers [15], nanorods [16] and nanowires [17], has exhibited excellent superhydrophobicity, with a CA larger than 150°. A vertically aligned carbon nanotube forest functionalized by poly(tetrafluoroethylene) with a superhydrophobic surface using the nanoscale roughness has been reported by Lau and co-authors [18]. The aligned silicon carbide nanowires also show excellent superhydrophobic property after functionalized with perfluoroalkysilane [19]. Thus, the specific chemical functionalization is a crucial factor to achieve superhydrophobicity [20–25], since the …