Some methodical aspects and applications of freeze-etching in polymer research

The freeze-etching method is used for investigating the morphology of aqueous polymer systems, e.g. network-like segregation structures of cryofixed polymer solutions and real network structures in polymer gels. The cooling rate, which is decisive for cryofixation of specimens, is measured by a thermocouple and a pyroelectric element in different coolants. The effect of the cooling rate on the freeze-etching structure of polymer solutions, polymer gels and a 10% aqueous glycerol solution as a model substance is determined and compared. The increase of the cooling rate in polymer gels results in maintaining the original network structure, in smaller segregation compartments in polymer solutions and in smaller crystallites in the cryofixed ice matrix.