MWD of Living Polyacrylates Fractionated by Chromatography via Chain-end Modification

Abstract

Selective separation of living and dead polymer chains can be accomplished by exploiting differences in chain-end functionality, as characteristic terminal groups introduced into living chains interact with chromatographic stationary phases. Compared with polystyrene, the relatively higher polarity of the ester-containing acrylate backbone leads to interactions with polar stationary phases during chromatographic separation, partially masking the contribution of chain-end functionality and hindering efficient end-group-dependent fractionation. To overcome this limitation, we introduce a strategy that enhances chain-end polarity through dihydroxyl functionalization via azidation and copper(I)-catalyzed azide–alkyne cycloaddition. The resulting polymers exhibit stronger end-group interactions with a polar stationary phase, enabling effective separation of living and dead chains by solvent-gradient high-performance liquid chromatography under near-critical adsorption conditions. This approach allows distinct fractionation of the living population, whose molecular weight distribution was verified by matrix-assisted laser desorption ionization–time of flight mass spectrometry to follow a Poisson distribution. By establishing a chromatographic separation framework compatible with intrinsically polar acrylate backbones, this study provides direct experimental access to living polyacrylate populations and expands analytical capabilities for precision polymer synthesis.