Replication extraction replicas

Examples of replicating plastics (along with their solvent) are cellulose acetate (acetone), gelatin (water or dilute sodium hydroxide), acrylic resin (acetone) and poly(vinyl alcohol) (water). Solutions of 2% formvar in chloroform or dioxane and 1-4% collodion in amyl acetate are appropriate for rough surfaces where tapes and films are not easily removed. Washing and extractions are similar to those described above for one stage replicas. A major problem can be the incomplete dissolution of the plastic replica which interferes with TEM imaging. 

Extraction or detachment replicas provide a replica of the surface along with some thin fragments of the actual specimen. The advantage is that the surface topography is recorded and anal5 ical experiments, such as electron diffraction, may also be conducted. The method is complementary to microtomy or ultrasonication. Methods for such replication are similar to those described above for single and double stage... 

Figure 10.19 (a) Replica of an etched surface of isotactic polystyrene crystallised at 215°C in the form of a thin film. Replication involved an extraction procedure whereby a thin film of crystalline material remained adhering to the carbon replica, (b) Electron diffraction pattern from the replica... 

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