Energy filtering transmission electron microscopy of polymers – Benefit and limitations of the method

Energy filtering transmission electron microscopy (EFTEM) of polymers can often be successful where conventional methods fail due to insufficient contrast. A necessary prerequisite is that heteroatoms are contained in one of the phases to be discriminated. After an introduction of the method and a consideration of contrast in polymer systems, it is shown how and under what conditions EFTEM can contribute to the solution of typical problems in polymer research. The examples given cover representative areas from the fields of polymer blends, block copolymer morphology, structure of interpenetrating networks, film formation of water borne coatings, and organic-inorganic composites. All examples have in common that conventional TEM fails to yield the desired information on structure and composition, while EFTEM proves to be successful. Problems encountered upon interpretation of results are discussed, and ways to avoid artifacts are shown.