Complex nano-assemblies of polymers and carbon nanotubes

Since the discovery of carbon nanotubes in 1991 [1], researchers have envis aged potential applications such as nanoscale electronic circuits and the c onstruction of complex carbon-based nano-machines. Thus, the assembly of ba sic building blocks of complex nano-architectures, such as conjugated polym ers and nanotubes, has been a driving goal of much of the nano-science comm unity. A first step towards realizing this goal may be the attachment to, o r modification by carbon nanotubes of structures such as polymers. This lea ds to the possibility of assembling individual polymer molecules onto carbo n nanotubes with the net effect being the modification of the polymer's ele ctronic properties and structure in a predictable way. To accomplish this, clearly, a more detailed understanding of the interactions between conjugat ed polymers and carbon nanotubes must be sought. In this paper, we describe the assembly of the polymer, poly(m-phenylenevinylene-co-2,5-dioctoxy-p-ph enylenevinylene) (PmPV), into a coating around single-walled carbon nanotub es. Using scanning tunnelling microscopy, and scanning tunnelling spectrosc opy, we demonstrate that the low-energy electronic structure of the assembl ed material is dominated by the one-dimensional nature of the nanotube as r eflected in van Hove singularities. Further, we examine the modifications t o electronic structure at higher energies using spectroscopy, which suggest s that the polymer's electronic structure is altered by the introduction of nanotubes. (Some figures in this article are in colour only in the electronic version) .