The Polymer Society of Korea

Abstract

In reversible deactivation radical polymerization, block extension increases the fraction of terminated chains, significantly reducing the proportion of living species. Living chains molecular weight distribution follow a Poisson distribution, making their isolation essential for enabling high-performance multiblock and functional materials. Here, we report the first separation of living chains from poly(benzyl acrylate-block-styrene) (PBzA-b-PS) block copolymers synthesized via activators regenerated by electron transfer atom transfer radical polymerization (ARGET ATRP). Based on our earlier work with poly(benzyl acrylate) homopolymers, we used high-performance liquid chromatography (HPLC) to separate the living fraction. Bromine termini were converted to azides and subsequently functionalized with polar alkynes via copper-catalyzed azide-alkyne cycloaddition (CuAAC), enhancing polarity contrast between living and terminated chains. HPLC enabled successful isolation of the living chains, with size-exclusion chromatography confirming a narrow dispersity of Đ ≈ 1.017. Preliminary matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS) revealed a near-Poisson distribution. This approach demonstrates the feasibility of chain-end-defined purification in complex block copolymer systems and expands the applicability of living chain separation beyond homopolymers.