Nanotubes of pristine poly(3-hexylthiophene) with modulable conductive properties: the interplay between confinement-induced orientation and interfacial effects.

Here we investigate nanotubes of poly(3-hexylthiophene) (P3HT) prepared by solvent casting using highly ordered AAO (anodized aluminum oxide) membranes as templates. Upon varying the thickness of the nanotubes between 13 nm and 44 nm, a rise in conductivity by five orders of magnitude is observed. For 44 nm thick P3HT nanotubes, a conductivity value higher than in the bulk is reported. The mechanism of this enhancement effect is evidenced by X-ray scattering structural investigations revealing an orientation of the crystalline domains along the long axis of the nanopores. Nanoconfinement in nanopores could represent thus a powerful tool to modulate, within many orders of magnitude, the conductive properties of conjugated polymers and give rise to nanomaterials exhibiting better properties than in the bulk.