Anomalous diffusion, amorphous polymer

A brief review is presented of the theories describing transport processes in binary solutions of an amorphous, uncross-linked polymer and low molecular weight solutes. At present, there exists no theory capable of describing diffusion in polymer-solute systems over the entire concentration range. No general theory has been formulated to describe diffusional transport under conditions where viscoelastic effects are important. However, methods have been developed to anticipate conditions under which anomalous effects can be expected (2-2). This brief review is limited to the theories applicable for concentrated polymer solutions under conditions where the classical diffusion theory holds. 

The finding of anomalous diffusion in gas transport through amorphous polymers by TSA was bom out completely by MD. For a favourable case of fast diffusion, MD could detect the crossover from short-time motion inside cavities to the anomalous diffusion, and then to the Einstein regime. Anomalous diffusion must be expected for all transport of light gases through amorphous polymers. 

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