Gas phase sorting of fullerenes, polypeptides and carbon nanotubes (Kopie 1)

Sorting of nanoparticles is essential for many future nanotechnologies. Nanoparticles can generally be sorted by their different physical or chemical properties. The objective is to prepare or enrich a particular species with a distinct property. In the case of carbon nanotubes the sorting of species with different metallicity is essential for many applications such as the realization of field effect transistors, light emitting diodes or conducting wires. Here sorting can for instance be achieved by exploiting the tube’s dielectric properties in a liquid environment. Also, chemical methods for the selection and separation of carbon nanotubes are currently being investigated.
Complementary to these efforts, the manipulation of large clusters and molecules in the gas phase has also attracted a growing interest over recent years, in particular with applications in molecule metrology. Since many nanoparticles, among them biomolecules or carbon nanotubes, exist in various different isomers and conformations, it is intriguing to investigate sorting methods in the gas phase which select the particles according to their polarizability-to-mass ratio α/m instead of their mass alone.
A large number of classical deflection experiments have been performed in the past (for a review see) which employ the deflection of a well-collimated neutral beam in the presence of a static transverse inhomogeneous electric field. In this
arrangement, one can usually chose between a wide molecular ray of high flux or a narrow beam with a lower total signal whose lateral shift can be determined with higher precision.

Hendrik Ulbricht, Martin Berninger, Sarayut Deachapunya, André Stefanov and Markus Arndt

Nanotechnology 19 (2008) 045502 (6pp)