In-situ formation of supramolecular aggregates between chitin nanofibers and silver nanoparticles

• Published in: Carbohydrate polymers 2017-10, Vol.173, p.295-304
• Main Authors: Wijesena, Ruchira N., Tissera, Nadeeka D., Abeyratne, Charith, Bangamuwa, Osura M., Ludowyke, Natalie, Dahanayake, Damayanthi, Gunasekara, Sunanda, de Silva, Nuwan, de Silva, Rohini M., de Silva, K.M. Nalin
• Format: Article
• Language: English
• Subjects: Chitin; Chitin nanofibres; Silver nanoparticles; Supramolecular aggregates
• ISSN: 0144-8617; 1879-1344
• DOI: 10.1016/j.carbpol.2017.05.065

[Display omitted] •In situ aggregate formation between silver nanoparticles and chitin nanofibers.•Presence of chitin nanofibers AgCl is photo-reduced followed by reduction with NaBH4.•The system became unstable and formed a precipitate upon reduction.•Aggregate structure was analyzed using different analytical techniques.•Aggregate is made of wrapped chitin nanofibers on silver nanoparticles. Chitin and chitin derivatives have gained significant research interest over the years due to a number of beneficial properties that can be exploited in various application fields. Particularly, interactions between their nanostructures and other nanomaterials are of great interest. In situ photo-reduction of AgCl in chitin nanofiber aqueous dispersions resulted in significant loss of colloidal stability of both chitin nanofibers (CNF) and silver nanoparticles. UV–vis spectroscopy was used to characterize the extinction profiles of in-situ prepared CNF and several silver nanoparticle mixtures over the reaction steps. High resolution TEM characterization of the resulting structures indicated the presence of the aggregated form of nanofiber and nanoparticles. Energy filtered TEM analysis confirmed the existence of both CNF and silver nano particles in the aggregate, with silver in its chemically reduced state (Ag(0)). FT-IR, and 13C solid state NMR revealed the presence of strong interactions between Ag and CNF through hydroxyl and carbonyl moieties of the CNF structure. It was concluded that these interactions led to the formation of a supramolecular aggregate in the in-situ mixture as a result of wrapping of CNF around photo-reduced silver nanoparticles which resulted in the colloidal instability.