Silanization of Cotton Fabric to Obtain Durable Hydrophobic and Oleophobic Materials

Developing durable hydrophobic and oleophobic textiles using simple and environmentally responsible techniques remains a challenge. This study aimed to determine how the structure of organosilicon silanes-specifically the type of functional group (fluorinated alkyl, long alkyl, or benzyl group) and the presence of an ester linker formed via the thiol-Michael addition-affects the wetting behaviour of cotton fabrics. Five silanes were synthesized and applied using a mild pad-dry-cure silanization process. The modified fabrics were evaluated through water and oil contact angle (WCA, OCA) measurements, water absorption tests, droplet-stability analysis, and washing-durability assessment. All treated samples exhibited hydrophobicity, while the silane containing a C6 perfluoroalkyl chain provided both hydrophobic and oleophobic performance. This fabric showed a WCA of 152° and an OCA of 126° (hexadecane), which remained essentially unchanged after 10 washing cycles (153° and 126°, respectively). Water absorption decreased by 91%, and droplets remained stable for at least 30 min. SEM, and SEM-EDS confirmed the presence and uniform distribution of the silane coating. These results demonstrate that short-chain fluorinated silanes and long-chain alkyl silanes can form durable low-surface-energy layers on cotton using a straightforward and efficient process, offering a promising route for high-performance functional textiles.