Incorporation of melanin nanoparticles improves UV-shielding, mechanical and antioxidant properties of cellulose nanofiber based nanocomposite films

The featured work reports the preparation, characterization and various properties of melanin nanoparticle (MNP) reinforced cellulose nanofiber (CNF) based nanocomposite films. The CNF was extracted using a combination of chemical and physical methods. The MNP was isolated from a natural source sepia ink by following a simple centrifugation technique and used as a functional nanofiller to fabricate the CNF/MNP nanocomposite films. The prepared nanocomposite films were characterized in terms of morphology, structure, chemical interactions, optical properties, surface hydrophobicity, mechanical properties, thermal stability and antioxidant activity. The MNP was shown to be evenly dispersed in the CNF matrix and biocompatible with cellulose matrix to form the nanocomposite films. Incorporation of MNP enhanced the ultraviolet blocking, mechanical properties, hydrophobicity and water vapor barrier properties of the nanocomposite films. The developed nanocomposite films also showed strong antioxidant activity. The crystalline structure, crystallinity and thermal stability of the nanocomposite films were not affected meaningfully. The sepia ink isolated MNP has a very good prospective to be used as a nanofiller for the preparation of CNF based nanocomposite films.