Antibacterial properties of silk fabric treated with silver nanoparticles

Silk is hygroscopic and is affected by microorganisms easily. Hence, treatment with antimicrobial agents can facilitate to make silk resistant to microbes. Silver nanoparticles have been attempted by researchers and applied as antimicrobial chemical finish on textiles. Silk has also been applied with silver nanoparticles through exhaust method to obtain antimicrobial properties. However, use of cross-linking agents such as 1,2,3,4 butane tetra carboxylic acid (BTCA) for entrapping silver nanoparticles in the interstitials of the silk molecular chain has not been attempted. The present study is focused on the application of BTCA on silk in the presence of sodium hypophosphite (SHP) simultaneously using silver nanoparticles has been done by pad-dry-cure (2dip/2nip) method. Application of 6% BTCA with 3% SHP and 250 ppm of silver nanoparticles gave satisfactory antimicrobial properties. Infrared spectroscopic (FTIR) studies showed good cross-linking of BTCA. X-ray diffraction studies depict that the crystal structure and crystallinity % of treated silk did not change due to the treatment. SEM studies showed the impregnation of silver nanoparticles on to the fibre matrix. Different physical properties of silk fabric did not change due to the treatment. Based on the studies, it is inferred that BTCA cross-links with silk fibroin at the carboxyl and amine groups, create a lattice void and trap silver nanoparticles giving durable antimicrobial finish.