Self-Assembly of Helical Polyacetylene Nanostructures on Carbon Nanotubes

The self-assembling of helical polyacetylene (PA) nanostructures on single-walled nanotubes (SWNT) is studied using molecular dynamics (MD) simulations. The results indicate that SWNT can activate and guide the polymer chains helically wrapping onto it through van der Waals interaction and the π–π stacking interaction between the polymer chain and the outer surface of SWNT. The effects of SWNT diameter, SWNT chirality, and PA chain length on the configuration of the nanostructure have been extensively examined. It is found that a DNA-like double helix of two PA chains appears when the diameter of SWNT is larger than about 13.56 Å, the SWNT chirality has a negligible effect on whether the helical process could happen, and the two PA chains can interact with each other and then influence the formation of the perfect double helix. The geometrical structures between PA and SWNT may trigger enormous interests in chemical functionalization and helical polymer synthesis, which may eventually be beneficial for fabricating nanoscale devices. In addition, the self-assembly process of helical nanostructures on SWNT may also be helpful for understanding biological systems at the molecular level and for developing new materials.