The sections were stained by exposure to the vapors of a ruthenium tetroxide
solution for 20 min at room temperature.
Before the TEM observation, the sample taken from the core part of molded bar specimen was microtomed at - 140[degrees]C to an ultrathin section of 70 nm thickness and then stained by ruthenium tetroxide
The samples were previously treated by staining with ruthenium tetroxide according to the technique proposed by Montezinos (31).
In view of its reactivity with many compounds including olefines, ruthenium tetroxide is commonly used as a staining agent for polymers in order to enhance image contrast by increasing the electronic density of those regions that can be oxidated at a higher rate, like the amorphous regions in polyethylene.
The ruthenium tetroxide solution was prepared from ruthenium (III) chloride hydrate and sodium hypochlorite.
It was found that for these specimens, the PE phase (identified by the clearly visible crystallites) was more heavily stained by the ruthenium tetroxide than the PS phase.
The film was vapor stained for 15 minutes over a ruthenium tetroxide solution (19).
This sample was vapor stained with ruthenium tetroxide, which reacts with the phenyl groups in the polystyrene blocks.
The oil is unreactive towards ruthenium tetroxide and thus does not contribute to the staining effect.