Surface energy maps of nanostructures: Atomic force microscopy and numerical simulation study

Topography and surface energy distribution of etched graphite were examined by atomic force microscopy (AFM). AFM images show atomic monolayer deep circular holes (etch pits). At certain imaging conditions, these etch pits appear surrounded by rims. Numerical simulation of AFM images reveals that the rims are formed due to an increased surface energy zone at the edges. The vertical dimension of the rim correlates with the magnitude of the local surface energy. Such a correlation between the imaging features and the surface energy profiles can be used to demarcate local chemical constituents in a composite nanomaterial. (C) 2003 American Institute of Physics.