Hydrophilic and antibacterial surface functionalization of polyamide fabric by coating with polylysine biomolecule

Polyamide (PA) fiber is the second largest synthetic fiber, and extensively applied in underwear, outerwear, sports/leisure wear and decorative fabrics. However, PA textiles have poor wearing comfort resulting from their inherent hydrophobicity, and do not possess antibacterial function which is vital for preventing bacterial infections. To address these issues, this study employed polylysine (PLL) biomolecule to fabricate the hydrophilic and antibacterial surface on PA fabric by a dip coating technique. The Schiff base reaction between the aldehyde groups of glutaraldehyde and the amino groups of PLL and PA fiber was utilized to increase washing resistance. The effects of the dip coating conditions of PLL on the hydrophilicity of PA fabric were studied by the wetting time of water droplet. The hydrophilicity imparted to PA fabric by PLL coating was further confirmed by water contact angle, moisture adsorption and capillary effect tests. The PLL coated fabric exhibited excellent hydrophilic and antibacterial properties with good washing durability. The functional surface of the PLL coated fabric was proved by scanning electron microscope, X-ray photoelectron spectroscopy, and charge effect. The present research suggests that PLL biomolecule can be used as a surface coating agent for simultaneously imparting hydrophilic and antibacterial functions to PA fiber.