The Impact of Band Broadening on Molar-Mass Determination of Narrow-Distribution Polymer by Size-Exclusion Chromatography

A systematic study of the effects of band broadening (BB) in size-exclusion chromatography (SEC) on Poisson molar-mass distributions (MMDs) is carried out. Such distributions apply for polymer standards used for SEC calibration, and they are a good model for the MMD from any quasi-living polymerization, including reversible-deactivation radical polymerization (RDRP). BB is simulated using the exponentially modified Gaussian model, which is shown to work excellently for actual polymer standards. A series of simulations with this model revealed how BB parameter values affect number-average degree of polymerization and polydispersity index from SEC. It is shown that the skewness parameter is particularly important in these considerations. Many of the obtained trends echo ones from RDRP, suggesting that BB has been making a hitherto unsuspected-indeed uninvestigated-contribution to deviations from ideal behavior in such systems.