Dynamics of hydroxyapatite and carbon nanotubes interaction

The aim of this work is to study the interaction of hydroxyapatite (HA) with carbon nanotubes (CNTs). The HA, a biomaterial with known low mechanical resistance, is put to interact with CNTs known for having high mechanical resistance. The systems studied were complexes formed by hydroxyapatite and pristine and functionalized CNTs with x = 5%, 10%, 15%, 20%, 25% concentration of hydroxyl (OH) and carboxyl (COOH) organic groups. The software used to perform the simulations was GULP together with the DREIDING force field. The lattice dynamics revealed that pristine CNTs had lower interaction with HA due to their high chemical stability whereas the functionalized CNTs interacted better with the HA matrix. The dependence of mechanical properties such as bulk and Young modulus and the Poisson's ratio with the percent of functionalization indicate the possibility to modify the elastic properties selecting the type and concentration of functionalization, giving is such a way, control over the mechanical properties of the complexes.