OsO4 staining

Fig. 33 TEM micrograph revealing peculiar two-component, three-phase morphology OSO4 staining. Note cylinder-like PS domains inside PB phase. Morphology is schematically illustrated in insert. From [102]. Copyright 2003 WUey...

Figure 6.9. Transmission electron micrograph of PEO/PS block copolymer (70.0% PS) cast from ethylbenzene (OSO4 staining). The white markers are 1 nm apart. (Crystal et a/., 1970.)...

CF4 02 RIE is used to transfer the pattern of a monolayer of OSO4 stained spheres into the substrate,... 

Some aspects of morphology can be observed directly by transmission electron microscopy of stained and ultramicrotomed thin sections. The most successful staining method, developed by Kato, makes use of osmium tetroxide, which attacks the double bonds in diene type polymers. The OSO4 staining technique can also be used with other active groups, such as polyurethanes.Many saturated or nonreactive polymers are not easily studied by transmission electron microscopy, unfortunately, because they cannot be stained. Other aspects of morphology, such as phase continuity and interface characteristics, are best determined by combining chemical and dynamic mechanical spectroscopy methods with electron microscopy. 

OSO4 staining - when there is at least 5% unsaturation in the polymers being investigated, e.g. NR/EPDM, bromo isobutylene isoprene rubber/ neoprene (BIIR/neoprene). 

Several two step reactions have extended the range of OSO4 staining to materials that cannot be stained directly. Alkaline saponification at boiling temperature foUowed by reaction of the... 

Figure 1.46 TEM micrographs of a multicomponent blend (PE/PPE/HIPS/ SEPS) stained with different agents left OSO4 staining mainly shows the rubber particles (dark) embedded in the PS/PPE phase ...

Figure 1.51 Two sections from a section series from the same place of a HIPS sample section 7 (at the bottom) Is about 700 nm deeper in the sample than section 1 (at the top), changes In the shape and size of the salami particles are visible (OSO4 stained,...

Figure 5.1 Relatively large rubber particles with PS inclusions ( salami particles ) in HIPS OSO4 stained, ultrathin section, TEM...

Hgure 5.3 Core-shell particles (rubber shells with PS inclusions and SAN grafted surfaces) OSO4 stained, UDS, TEM... 

Polymers containing unsaturated rubber and semicrystalline polymers are often effectively stained using osmium tetroxide. What about materials that do not show such differential staining Two examples will be described where reactive (unsaturated) materials are included into the polymer to provide reaction sites. Inclusion of a stainable unsaturated polymer was shown for cellulosics [81] and synthetic fibers [106]. The initial work was focused on improvement of properties of cellulosics by inclusion of an elastomer between the microfibrils. OSO4 staining... 

Fig. 4.12 "Longitudinal sections of polyester fibers shown by TEM (A) do not have any interesting morphology, unstained, except for particles of Ti02 (arrows). Impregnation with isoprene followed by OSO4 staining results in electron dense longitudinal striations and elongated voids (arrows) adjacent to the particles (B).

Several two step reactions have extended the range of OSO4 staining to materials that cannot be stained directly. Riew and Smith [195] exposed rubber modified epoxy resins to OSO4 dissolved in tetrahydrofuran (THF), which diffuses into the epoxy, speeding the reaction with the rubber. Aqueous formaldehyde was used in the staining of polyamides [1%]. Thin films of... 

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