CHARACTERIZATION OF POLYMER BLENDS AND BLOCK COPOLYMERS BY CONVENTIONAL AND LOW-VOLTAGE SEM

Methods for characterizing block copolymers and polymer blends have been developed. Results from unstained and ruthenium tetroxide‐stained samples obtained by scanning electron microscopy at various acceleration voltage and by transmission electron microscopy are presented. The contrast in secondary images between components in stained polymer blends, where one component is preferentially stained, is maximized at higher acceleration voltage (10–25 keV). For measurement of particle size and shape, this is the preferred operating condition. To obtain high‐resolution images showing surface topography and fine structure, such as 20 nm domains in block copolymers, low‐voltage (<5 keV) imaging is preferred. Observation of the 20 nm domain structure in hydrogenated styrenebutadiene‐styrene shows that the spatial resolution now possible by scanning electron microscopy is comparable to that obtained by the traditional method of transmission electron microscopy. Copyright © 1990 Foundation for Advances in Medicine and Science, Inc.