Efficient cross‐section preparation method for high‐resolution imaging of hard polymer composites with a scanning electron microscope

Summary Characterization of distribution and arrangement of filler particles in polymer composites is of primary importance to understand and maximize their mechanical, electrical and thermal properties. An innovative procedure that allows reliable and straightforward preparation of cross‐sections of polymer composites with the use of mechanical polishing, ion beam etching and soft gaseous etching is presented in this paper. Because of the inherent difference between the organic amorphous matrix and the inorganic crystalline nature of composite fillers, the removal of matrix layers at the surface of the cross‐section at the expense of the inorganic materials allowed characterizing the composite filler particles structure and distribution over the surface. Since beam broadening did not occur before the beam hit the nanoparticles, high‐resolution imaging in the scanning electron microscope was possible and true dimensions and orientation of the particles were observed. This provided more flexibility in selecting the primary beam voltage; especially, the use of low beam energy greatly improved the image contrast and reduced charging effects resulting from the primary electron beam bombardment. It was shown that only polymers with a carbonated main chain could be etched selectively by the gaseous etching process.