Fabrication of fatty acid based superhydrophobic metallic surface functionalized with Al2O3 nanoparticles for moist air condensation

We present a cost-effective and durable coating using fatty acids, such as lauric and stearic acid, with and without functionalization using Al₂O₃ nanoparticles to enhance the hydrophobicity of aluminum (Al) substrates. We varied and optimized the weight percentage of the chemical composition in fabricating the durable coatings to increase the efficacy of the moist air condensation. The optimized coated surfaces were characterized using atomic force microscopy (AFM) for their order of roughness, scanning electron microscopy (SEM) for their morphology, and Fourier-transform infrared spectroscopy (FT-IR) for their chemical composition. The wetting behavior of the surfaces was evaluated via water contact angle measurements, and their performance for moist air condensation was analyzed. Our results demonstrated that the functionalization of Al₂O₃ nanoparticles in fatty acid reduces the surface roughness, minimizing the contact angle's hysteresis. We found a significant enhancement in the water condensation rates with minimum hysteresis with an increase of ∼105 % for lauric acid–Al₂O₃ and ∼ 48 % for stearic acid–Al₂O₃ coated Al surfaces, respectively. Additionally, fatty acid based superhydrophobic metallic surfaces functionalized with Al₂O₃ nanoparticles have excellent durability for 150 days in a moist air environment.