Measuring the size of polymers with negative radii using MALS/QELS: an exploration of the thermodynamic radius

The concept of 'size' in polymer science can have several interpretations, including definitions that rely on either statistical or equivalent-hard-sphere measures of the spatial extent of macromolecules in solution. A definition such as that of the equivalent thermodynamic radius (R(T)), which relies on the second virial coefficient of the polymer solution, offers the possibility of a zero or even a negative size parameter for macromolecules,...