Leather, a collagen-based natural material, exhibits excellent mechanical strength, breathability, and flexibility; however, its inherent hydrophilicity leads to significant water absorption, limiting its application in moisture-exposed environments. To address this demand, we developed sustainable superhydrophobic coatings on a leather matrix. Here, we use HMDS (hexamethyldisilazane)-modified SiO2 nanoparticles (superhydrophobic SiO2) as a base material to achieve superhydrophobicity. This work presents a single-step, room-temperature modification route for generating superhydrophobic SiO2, eliminating the need for complex multistep procedures. Although superhydrophobic SiO2 is well established, its compatibility with a diverse range of polymers remains unexplored. In this study, hybrid micro/nanocomposite coatings were prepared using various types of polymers such as polyurethane (PU1, PU2, PU3, PU4, PU5), acrylic resin (AR1, AR2), and nitrocellulose lacquers (NC1, NC2) to impart hydrophobicity to leather surfaces. Superhydrophobic SiO2 nanoparticles were incorporated into the polymer matrices, with 3-aminopropyltriethoxysilane (APTES) employed as a coupling agent to enhance interfacial compatibility between the nanoparticles and polymers. The prepared coatings were applied onto the leather surface by a facile spray-coating process. Different types of single and combination coating formulations were done, and the coated leathers exhibited water contact angles in the range of 130°–156° for various systems. Among the formulations studied, AR1- and PU2-based coatings showed superior performance, achieving water contact angles of 156° and 154° with low sliding angles of 8° and 10°, respectively. The coatings also demonstrated excellent fastness properties and abrasion resistance without compromising the intrinsic properties of leather. This work provides a practical and sustainable surface-engineering approach for developing durable hydrophobic leather materials and highlights its potential for versatile leather finishing applications suitable for advanced footwear, apparel, and upholstery uses.
Sangeetha et al. (Fri,) studied this question.