Strategic Role of Carbon Nanotube Functionalization on the Multifunctional Properties of Structural Epoxy Nanocomposites

Carbon nanotubes (CNT) have received great attention as nanofillers for epoxy structural nanocomposites, due to their rare combination of mechanical, electrical, thermal properties, and others. Furthermore, the surface of the carbon nanotubes can be easily transformed with a variety of characteristic atoms or groups of atoms conferring specific and desired properties. Different kinds of functionalization (covalent and non-covalent) can be performed. A very recent and hopeful strategy capable of modifying the surface of carbon nanotubes, without endangering their structural integrity, is the non-covalent modification of CNT walls with specific molecules that show a marked similarity with the graphitic structure of carbon nanotubes. The aim of this work is to enhance the interactions of CNT with epoxy matrices to allow much better nanofiller dispersion within the epoxy polymer through carbon nanotube modification. The obtained results highlight that the performed functionalizations are suitable for designing carbon-based nanocomposites with improved structural and functional properties. Specific surface modifications of CNT walls are carried out using supramolecular chemistry specialized in non-covalent interactions. These weak and reversible forces act advantageously by activating the self-repairing functionality in the nanofilled resins. The morphology of nanodomains and the interfacial interactions between nanocharge and hosting resin are investigated by Tunneling Atomic Force Microscopy (TUNA). The nanocomposite performance is strongly affected by the performed functionalization.