One-step fabrication process of superhydrophobic green coatings

In general, creation of superhydrophobic surfaces is composed of two steps: (i) creation of a rough surface and (ii) passivation of the surface with the low surface energy molecules or coatings. Superhydrophobic properties cannot be achieved on a surface without these two essential factors fulfilled. In the present work we have demonstrated that superhydrophobic silver films on copper (Cu) substrates can be created in just a one-step process via galvanic reactions by immersing the Cu substrates in silver nitrate solution containing benzoic acid, simplifying the complexity of two different steps involved in the former method. Silver films were also fabricated using similar process without benzoic acid for comparative studies. The X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FTIR) confirmed the formation of benzoic acid incorporated silver films. Scanning electron microscopy (SEM) images showed micro-nano structured leaf-like and flower-like morphological features in the films prepared without and with benzoic acid, respectively. Benzoic acid incorporated flower-like silver films demonstrated water repellency as the water drops rolled off those surfaces whereas complete absorption of water drops were encountered on the leaf-like silver surfaces prepared without benzoic acid.