Effects of the aspect ratio of multi-walled carbon nanotubes on the structure and properties of regenerated collagen fibers

Collagen is a natural one-dimensional nanomaterial. Multi-walled carbon nanotubes (MWNTs) have been previously shown to interact with biomolecules and to have promising applications in reinforced biopolymers for tissue engineering and regenerative medicine. In this work, collagen/MWNT composite fibers are prepared using dry-jet wet-spinning technology. Three types of MWNTs with aspect ratios of 40, 150, and 4000 are used to investigate the effects of the MWNT aspect ratio on the properties of the composite fibers. There results show that there are strong molecular interactions between the MWNTs and collagen molecules. The mechanical properties and thermal stability of the composite fibers are significantly improved compared to those of the collagen fibers. The diameter and aspect ratio of the MWNTs are the main factors affecting the self-assembled structure of the collagen molecules, the alignment of the microfibrils, and the mechanical and thermal performance of the composite fibers.