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.