Poly-para-phenylene-ethynylene assemblies for a potential molecular-nanowire: an SFM study

The self-assembly of a poly-para-phenylene-ethynylene (PPE) derivative cast onto muscovite mica is investigated by Tapping Mode Scanning Force Microscopy. The film morphology depends on the concentration of the PPE in the casting solution. At high concentration a grain morphology with some linear aggregates is observed. At low concentration PPE self-assembles into well defined and stable needles with a cross section with molecular dimensions. A model for the packing of the molecules in these supramolecular structures is suggested. Properly functionalised needles exhibit the molecular architecture of a molecular nanowire ready to be interfaced by metallic nanoelectrodes. (C) 1998 Elsevier Science B.V.