Eco-Friendly Superhydrophobic Coatings from Organosilane Sol–Gel Synthesis: Performance and Environmental Assessment

Superhydrophobic coatings offer promising solutions for a wide range of applications. However, many of the existing technologies rely on fluorine-based compounds that are harmful to human health and the environment. The aim of this study is to present a novel, eco-friendly approach to fabricate superhydrophobic surfaces using a one-step sol–gel synthesis of organosilane sols combined, followed by spray-deposition method. Conducted at 70 °C and employing non-toxic solvents such as water and ethanol, the process was designed to minimize environmental impact while achieving superhydrophobicity on the surface. The incorporation of organosilanes enabled the formation of a silica network that reduced surface energy, whereas the spray-deposition technique contributed to micro-nanoscale surface roughness; both emerged as crucial factors for superhydrophobicity. Furthermore, the influence of the tetraethyl orthosilicate (TEOS):Hexadecyltrimethoxysilane (HDTMS) molar ratio on wetting performance was systematically investigated. The synthesized solution was effectively deposited on various substrates, including metallic alloys (Ti-6Al-4V, Al 1050 H14, Cu-ETP), carbon fiber-reinforced polymer (CFRP), paper, cardboard, fabric, and glass. Surface morphology was characterized by Scanning Electron Microscopy (SEM), coupled with Energy Dispersive Spectroscopy (EDS), and chemical composition was confirmed by Fourier Transform Infrared (FTIR) spectroscopy. A cradle-to-gate life cycle assessment (LCA) using the CML 2001 methodology demonstrated consistent environmental improvements across all eleven impact categories relative to a PFAS-based baseline, with higher reductions in ozone layer depletion (−96.2%), terrestrial ecotoxicity (−81.3%), and eutrophication (−64.5%). These results establish a scalable, fluorine-free route to high-performance superhydrophobic coatings with significantly reduced environmental burden.