In-situ synthesis and characterization of silver nanoparticle decorated cotton knitted fabric for antibacterial activity and improved dyeing performance

This study reports the antimicrobial activity and improved dyeing performance of cotton knitted fabric by depositing silver nanoparticles on the surface. The cotton fabric is first treated with caustic soda (NaOH) of three different concentrations to activate the hydroxyl groups on the cellulose surface and then the nanoparticles are introduced on fabric surface by direct reduction of silver nitrate salt using ascorbic acid. The presence of silver nanoparticles on the fabric surface is clearly observed by scanning electron micrograph. The elementary analysis is done by energy dispersive spectroscopy and the chemical interaction of cotton fibre with nano silver is characterized by Fourier transform infrared spectrum. In this work, the antimicrobial activity on Ag deposited sample is investigated by quantitative analysis against both Gram positive (S. aureus) and Gram negative (E. coil) bacteria. Results shows a significant antimicrobial activity such as more than 90% bacterial reduction of both Gram positive and Gram negative bacteria are inhibited. The fabric sample is dyed with 2% direct dye and consequently the result shows very good performance in dye exhaustion, colour strength and fastness property. For instance, the incorporation of Ag nanoparticles increases 7% of dyestuff exhaustion and 15% of colour strength of the fabric. However, Ag nanoparticles deposited fabric loses its strength slightly due to the pretreatment using NaOH for the functionalization of cotton.