Non-leaching bactericidal cotton fabrics with well-preserved physical properties, no skin irritation and no toxicity

Abstract

We developed an isocyanate group containing quaternary ammonium salt (IQAS) as a potential antimicrobial finishing agent that can be stored in a high purity form for more than a year in dry environments to permit convenient transportation and storage. Additionally, we report a facile and eco-friendly finishing technique to fabricate durable antimicrobial cotton fabrics using IQAS as an antimicrobial finishing agent by a dipping–padding–drying process. IQAS was bound onto the surface of cotton fabrics by a covalent bond to obtain a cotton fabric with excellent bactericidal activity, tearing strength, breaking elongation, bending rigidity, water vapor permeability, surface roughness and smoothness. The antimicrobial rates of these fabrics reached 92.2% and 98.5% against gram-negative bacterium Escherichia coli and gram-positive bacterium Staphylococcus aureus, respectively, even after 50 laundering cycles. These values are much higher than the reference antimicrobial rates of AAA class antimicrobial fabrics, as well as those of conventionally finished cotton fabrics, indicating that the IQAS finished cotton fabrics maintained excellent antimicrobial activity even after long-term repeated launderings. Moreover, the results indicate that the IQAS-treated cotton fabrics could improve the breaking strength (increased by 13.5% in the warp direction and 20.3% in the weft direction), the bursting strength (increased by 11.9%), the air permeability (increased by 12.6%) and the hydrophilicity compared to untreated cotton fabrics. Additionally, our non-leaching antimicrobial cotton fabrics treated with IQAS were non-toxic and showed no skin stimulation. Therefore, IQAS and the antimicrobial finishing technique reported here have great potential applications in antimicrobial fabrics used in hospitals, hotels and other susceptible situations. An isocyanate group containing quaternary ammonium salt that permits convenient transportation and storage was developed as a potential antimicrobial finishing agent to fabricate excellent antimicrobial cotton fabrics with well-preserved physical properties and security using a dipping–padding–drying process.