Nanoindentation Investigation on Chitosan Thin Films with Different Types of Nano Fillers

Chitosan nanocomposite thin films were fabricated using two types of chitosan natural polymer (cross-linked chitosan (CLCS) and non-cross-linked chitosan (NCLCS)), with three different weight percentages nano-fillers (Graphene (G) and fullerene (F)). Nanoindentation tests were performed to investigate the local mechanical properties of the produced nanocomposite in comparison to the unreinforced chitosan thin films. Nano hardness values (H) and indentation modulus (E) were measured using 5 and 10 µm spherical indenters. The addition of nano fillers enhanced the hardness of both types of films with the amount of hardening being directly proportional to the fraction of nano filler added(p<0.001). Crosslinking has also significantly increased the hardness (p< 0.001). The larger indentation returned a lower hardness. The use of different radii nano indenters underlined the indenter size effect due to the differing strain fields. The promising mechanical properties resulting from this research will allow using the fabricated nanocomposites for tissue engineering, biomedicine, drug delivery, electronics, energy, surface coatings and packaging applications.