Electrostatic scanning force microscopy images of long molecules:: single-walled carbon nanotubes and DNA

Experimental measurements of the electrostatic properties of long molecules are presented in this work. It is shown that, in the case of carbon nanotubes, the electrostatic force between the scanning force microscopy tip and the sample enhances the network of nanotubes electrically connected to a metal electrode. On lambda-DNA molecules the same kind of experiments result in essentially no measurable electrostatic force due to the molecules. From this we conclude that X-DNA has a negligible electronic conductivity.