Development of Liquid-Repellent Cotton Fabrics through Short-Chain Perfluoroalkyl Substances-Modified Al ₂ O ₃ , MgO, and ZnO Nanomaterials

This work explores interactions among alumina oxide (Al2O3), magnesium oxide (MgO), zinc oxide (ZnO) nanoparticles, and the short-chain fluorocarbon surfactant SilnylFSJ (SY) in creating liquid-repellent cotton fabrics. Nanoparticles were modified via incipient-wetness impregnation with SY, yielding systems with varying fluorine levels. The thermodynamics and adsorption potential of SY on the nanoparticles were analyzed to elucidate the interactions between SY and the nanoparticles. Dispersion of SY-modified nanoparticles in probe liquids was evaluated using the Derjaguin, Landau, Verwey, and Overbeek (DLVO) theory to assess the surface free energy of nanomaterials. The most promising SY-modified nanoparticles were incorporated into cotton using a two-step layer-by-layer assembly with poly(vinyl alcohol) (PVA) as a binder. Liquid repellency was tested with liquids of varying polarity and surface tension. Results showed that higher hydroxyl content in the SY-modified nanoparticles led to strong complexation with the PVA, favoring the migration of the nanoparticles to the bulk coating, limiting the fluorine orientation outward the fabric surface, and reducing the repellency of the treated fabrics. Otherwise, lower hydroxyl and higher fluorine content at the nanoparticle surface enhances fluorine surface exposure and liquid-repellency performance. Among the tested systems, Al2O3-30SY/PVA@Cotton exhibited superior repellency [water contact angle of 163.1° and oil contact angle of 150.3°], even against low-surface-tension liquids and after repeated washing cycles. The high affinity of SY for the surface of Al2O3 nanoparticles, the feasible exposure of the Al2O3-30SY nanoparticles, and the formation of a micro/nano hierarchical structure on the surface of the fabrics are responsible for the liquid-repellent character. The findings highlight the critical influence of nanoparticle surface chemistry on PFAS integration and performance, providing a pathway for the rational design of advanced liquid-repellent textiles with reduced environmental impacts.