Understanding the Helical Wrapping of Poly(3-hexylthiophene) on Carbon Nanotubes

We studied poly(3-hexylthiophene) adhesion on single-walled carbon nanotubes via molecular dynamics simulations. We provide evidence that, in absence of the solvent, the polymer tends to unwrap and align to the nanotube. The helical organization in vacuo is metastable, and its lifetime is a function of the temperature and the polymer length. A kinetic model is here proposed according to which unwrapping is thermally activated with an energy barrier as small as 0.09 eV. Our results at room temperature reproduce the experimentally observed pseudohelical morphology of the polymer and confirm the role of the nanotube chirality. Furthermore, we provide evidence of a strong stabilization effect on the wrapped configuration because of neighboring polymer chains.