Development of a durable superhydrophobic PVDF nanocomposite coating

In the present research, the superhydrophobic coating was prepared through spray coating of a mixture of PVDF polymer and ZnO nanoparticles on aluminum substrate. Stearic acid was added to improve the dispersion of ZnO. The Taguchi orthogonal array L9 was used to optimize the fabrication process parameters, namely the percentage of stearic acid, ZnO and PVDF contents, and the spray distance from the substrate. Through the Taguchi method, it was found that the percentage of stearic acid and ZnO contents were the parameters making significant contribution toward improvement in wettability of PVDF coating. As the content of ZnO nanoparticles increased, the values of water contact angle increased, ranging from 122° to 159°, while the contact angle hysteresis and sliding angle decreased to 3.5° and 2.5°, respectively. The SEM results show that hierarchical micro-nanostructure of ZnO plays an important role in the formation of the superhydrophobic surface. In order to improve the durability of this developed superhydrophobic coating, a highly functional and biocompatible class of acrylics, known as cyanoacrylates (superglue) was added to composite. The results of tape test showed a significant improvement of coating adhesion on aluminum surface after adding the specific value of superglue