Electron Microscopy of Carbon-Loaded Polymers

It is very difficult to fully characterize the spatial distribution of particles in carbon-loaded polymers using traditional methods. One approach has been to cross-section the polymers, using ultramicrotomy techniques, to a thickness of 80–100 nm. These sections are then examined in a transmission electron microscope (TEM). Unfortunately, the information on particle dispersion obtained from such images is essentially two-dimensional in nature, and therefore does not lend itself easily to a three-dimensional interpretation. By increasing the thickness of the cross sections to 0.5 µm or more, one is able to utilize stereoscopic imaging techniques and obtain a three-dimensional image of the carbon particle dispersion. In this way, the characteristic dispersion of the carbon particles may be fully evaluated along a particular direction in the polymer film. Examples are given of the three-dimensional analyses of polymer films containing different carbon-particle loadings.