Specimen preparation method osmium tetroxide

Cellulose nitrate and cellulose acetate (CA) were among the first asymmetric, reverse osmosis membranes to be produced [150]. Plummer et al [1511 described 13 specimen preparation methods for the observation of CA membrane structures. They pointed out the lack of contrast in epoxy embedded sections and that one of the best stains, osmium tetroxide, reacts with the... 

Cellulose nitrate and cellulose acetate (CA) were among the first asymmetric, reverse osmosis membranes to be produced [121]. Plummer et al. [122] described 13 specimen preparation methods for observation of CA membrane structures. They pointed out the lack of contrast in epoxy embedded sections and that one of the best stains, osmium tetroxide, reacts with the polymer. Freeze fractured membranes were found by these authors to be of questionable value. In our experience, if care is taken, SEM study of fractured membranes can provide an informative view of the structure even though some structures collapse, and their sizes cannot be accurately determined. A method found acceptable was ultrathin sectioning of gelatin embedded wet membranes (TEM). The structure of CA membranes was shown by replication [123] and SEM [124]. 

In literature the following methods of preparation of polymer material specimen and studying their morphology are described methods of ultrathin section and films with contrasting of osmium tetroxide (10.11). method of replication of the brittle fractur-ed surface (11.12) oxygen and chemical etch of the polished surface or the fractured surface with the following replication for electron microscopy (11. 

Electron Microscopy The sample preparation was based on Kato s (10) osmium tetroxide staining technique and a two-step sectioning method. The specimens were exposed to O5O4 vapor and cut with a LKB ultratome III to get a 0.1 y slice. The electron micrographs were taken with an AEI 6B and a Phillips 300 transmitting electron microscope with a magnification of 95,000. 

---