Thermally triggered transition of fluid atomized micro- and nanotextured multiscale rough surfaces

Evaluation of fluid atomized spraying process parameters for poly(1,1,2,2-tetrafluoroethylene) coating such as `patternation' influencing on the distribution of droplets inside the spray boundary, air pressure affecting the 'nozzle flow-rate', air pressure assisted nozzle flow rate dependent 'droplet size', etc. gives state-of-theart hydrophobicity. The fabricated coating shows the transition from hydrophilic surface to hierarchical rough hydrophobic surface (WCA = 139 degrees +/- 3 degrees) at a temperature of 130 degrees C. Furthermore, the reflex of transition temperature on the hydrophobicity of coated system triggers the fabrication of hierarchical surface morphology culminating the maximum static water contact angle (147 degrees +/- 3 degrees) at an optimized temperature of 220 degrees C. Tailoring of nano-spindles over the multiscaled hierarchical rough surface by the synergistic effect of air-pressure assisted atomization parameters and thermally triggered transition temperature endowing ultimate hydrophobicity. Atomic force microscopy (AFM) characterization of the coating morphology confirms the triggered temperature by demonstrating the nano-spindled structure with RMS roughness (78 nm). Anti-corrosion performance of thermally triggered hydrophobic coating containing `air valleys' has been evaluated by using Tafel polarization curves proclaiming reduction in corrosion rate (0.001 mmpy) in the coated system. The results obtained by the following study possess tremendous potential to tailor-wet characteristics of the nano-textured atomized PTFE coating for diversified naval applications.