Metal salts Metastable phase

Many polymer-salt complexes based on PEO can be obtained as crystalline or amorphous phases depending on the composition, temperature and method of preparation. The crystalline polymer-salt complexes invariably exhibit inferior conductivity to the amorphous complexes above their glass transition temperatures, where segments of the polymer are in rapid motion. This indicates the importance of polymer segmental motion in ion transport. The high conductivity of the amorphous phase is vividly seen in the temperature-dependent conductivity of poly(ethylene oxide) complexes of metal salts. Fig. 5.3, for which a metastable amorphous phase can be prepared and compared with the corresponding crystalline material (Stainer, Hardy, Whitmore and Shriver, 1984). For systems where the amorphous and crystalline polymer-salt coexist, NMR also indicates that ion transport occurs predominantly in the amorphous phase. An early observation by Armand and later confirmed by others was that the... 

In order to prepare metastable states or possibly new phases of nano-scale metal particles, low temperature, kinetic growth methods should be used.(4J And atoms should be used, rather than salts or oxides since in the former case the high temperature reduction step can be avoided. In actuality, in recent years we have witnessed the development of several methods for the low temperature kinetically controlled growth of clusters from free atoms. Perhaps the most dramatic development has been the "cluster beam" approach where evaporated metal atoms are allowed to cluster in low temperature gaseous helium or argon streams.(5-2(9) Unusual cluster structures and reactivities have been realized. 

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