Poly(3-hexylthiophene) adhesion on Zinc Oxide Nanoneedles

We study the interface between poly(3-hexylthiophene) and wurtzite ZnO nanoneedles by molecular dynamics simulation. We provide evidence that the polymer is easily adsorbed on the nanostructured surface with the largest binding energy found when the chain is aligned to the needle axis. Helically wrapped polymer configurations are nevertheless possible, and they are found to be metastable with long lifetimes and small polymer mobility on the nanoneedle surface. The wrapped configuration lifetime has been compared with the case of carbon nanotube-based systems at finite temperatures and calculated to be much longer. The dependence of the adhesion energy on the polymer orientation is discussed and explained by a model, including strain, adhesion anisotropy, and nanoneedle shape effects (i.e., the presence of edges between facets).