A Deborah number for diffusion in polymer‐solvent systems

A Deborah number is introduced as a means of characterizing diffusional transport in amorphous polymer-solvent systems. Two types of temperature-penetrant concentration diagrams are constructed, and the various regions on these figures are identified by their Deborah number values. The utility of the diffusion Deborah number is demonstrated by using this dimensionless group to anticipate conditions under which thickness anomalies can be expected in sorption experiments for the atactic polystyrenepentane system.