Collect. Czech. Chem. Commun. 1989, 54, 1821-1829

QELSS diffusion data for moderately broad molar mass distribution polymer samples compared with data from classical gradient techniques

Bedřich Porscha, Simon Kingb and Lars-Olof Sundelöfb

a Institute of Macromolecular Chemistry, Czechoslovak Academy of Sciences, 162 06 Prague 6, Czechoslovakia
b Department of Physical Pharmaceutical Chemistry, Uppsala Biomedical Center, P.O. Box 574, S-751 21 Uppsala, Sweden


The differences between the QELSS and classical diffusion coefficient of a polydisperse polymer resulting from distinct definitions of experimentally accessible average values are calculated for two assumed specific forms of molar mass distributions. Predicted deviations are compared with the experiment using NBS 706 standard polystyrene. QELSS Dz of this sample relates within 2-4% to the classical diffusion coefficient, if the Schulz-Zimm molar mass distribution is assumed to be valid. In general, differences between the height-area and QELSS diffusion coefficient of about 20% may be found for Mw/Mn ~ 2, and this value may increase above 35%, if strongly tailing molar mass distribution pertains to the sample.