freely draining

https://doi.org/10.1351/goldbook.F02516
An adjective referring to a chain macromolecule the segments of which produce such small frictional effects when moving in a medium that the hydrodynamic field in the vicinity of a given segment is not affected by the presence of other segments. Thus, the solvent can flow virtually undisturbed through the domain occupied by a freely draining macromolecule.
Source:
Purple Book, 1st ed., p. 61 [Terms]