Preparation of carrageenan-based nanocomposite films incorporated with functionalized halloysite using AgNP and sodium dodecyl sulfate

Silver nanoparticles (AgNP) were prepared by reducing AgNO3 using ascorbic acid and adsorbed to halloysite nanotube (HNT) and treated with sodium dodecyl sulfate (SDS). The HNT-AgNP nanoparticles were used as a reinforcing filler to prepare carrageenan-based functional nanocomposite films. Transmission electron microscopy (TEM) results indicated that AgNPs were formed and adsorbed to the surface of HNT. The average diameter of SDS-treated HNT was 20-30 nm, which was smaller and more uniformly distributed than the SDS-untreated counterparts (>60 nm). The incorporation of HNT-AgNP nanoparticles increased the mechanical strength and UV-barrier properties of carrageenan films, and the composite films showed potent antibacterial activity against foodborne pathogenic bacteria, L. monocytogenes, and E. coli. Treatment with SDS increased the dispersion of HNT-AgNP nanoparticles in the carrageenan matrix, and also improved the mechanical properties, transparency, and antimicrobial activity of the carrageenan-based nanocomposite film.