Quantitative analysis of the staining of a polyisoprene-block-polystyrene

The staining of polymer systems by OsO4 is a well-established method to generate or increase the contrast of samples used for transmission electron microscopic investigations. OsO4 staining is very specific for polymers containing double bonds and can be used to stain block copolymers such as polyisoprene-block-polystyrene (SI). A quantitative analysis of the staining reaction of OsO4 with a polyisoprene-block-polystyrene copolymer using electron energy loss spectroscopy (EELS) is presented, which can determine the sample thickness of the ultrathin cut and the ratio of oxygen atoms, absorbed OsO4, to all of the carbon atoms, polystyrene and polyisoprene, contained in the sample.