Surface morphology analysis and hydrophobic property design for cotton clothing fabric based on vinyl-bearing silane coupling agent

Neat cotton clothing fabrics cannot show hydrophobic properties due to surface hydrophilic groups. Fiber fabrics with hydrophobic surfaces have attracted extensive study interest. Here, a hydrophobic cotton clothing fabric via a modification of silane coupling agent with terminal vinyl group was fabricated. Compared with neat cotton fabric, surface nano-roughness of the modified cotton fabric was improved with a low surface energy, making the latter become hydrophobic. The mechanism of molecular modification to cotton fiber surface was clarified. Covalent bonds were formed between coupling agent molecules as well as between coupling agent molecules and fabric surface via hydrolysis and dehydration condensation, which led to a stable modifying layer at fabric surface. The microstructure and hydrophobic properties of various cotton fabrics were investigated using infrared, scanning electron microscopy, and contact angle analyses. The water contact angle for the surface of 7-octene-1-ylsilane-modified cotton fabric arrives at 114.9 degrees. However, the surface of vinyltrimethoxysilane-modified cotton fabric cannot exhibit a hydrophobicity because of a short molecular length. Here, the hydrophobic functionalization for cotton fabric surface may be conducive to a large-scale fabrication of state-of-the-art clothing.