Exceptional behavior of anatase TiO2 nanotubes in axial loading: A molecular dynamics study of the effect of surface wrinkles

Abstract

Anatase TiO2 nanotubes have interesting properties which makes them a candidate for various applications. In this way, they may be exposed to different mechanical loadings. The aim of this research is to elucidate the mechanical behavior of anatase TiO2 nanotubes in axial loading using molecular dynamics simulations. Nanotubes with different radii and lengths are studied in 300 K both in stretching and compression. Our results show an interesting phenomenon occurring on the surface of these structures. As the radius of the nanotubes increases, their surface begins to wrinkle axially. This causes their axial behavior change dramatically. The threshold radius is observed to be 50 Å for length of 300 Å. This structural change softens the nanotubes in stretch loading while increasing the toughness by bestowing the structures more deformability. On the other hand, the nanotubes may entirely lose their stability in compression as the wrinkles form. As the radius or length of the anatase nanotubes increases, the possibility of wrinkle formation increases, strengthening these effects. Our results are important for the design of structures in which the anatase nanotubes are axially loaded, especially if the loading is compressive, to avoid structural failure.