Quasi-block copolymer libraries on demand via sequential RAFT polymerization in an automated parallel synthesizer

Rapid and Systematic Access to Quasi‐Diblock Copolymer Libraries Covering a Comprehensive Composition Range by Sequential RAFT Polymerization in an Automated Synthesizer

“…For the first polymerization step, a monomer conversion of 78% was obtained after 9 h at 85 °C. At this monomer conversion, the extent of radical termination should be relatively low while, at the same time, the conversion is sufficiently high to keep the level of n ‐butyl methacrylate (BMA) in the PMMA block low . The experimental number‐average molar mass () value for the PBMA macroRAFT agent (11 200 g mol −1 ) is in good agreement with the theoretical prediction (11 500 g mol −1 ), and the dispersity ( Đ ) is low (1.13) indicating a good control during BMA polymerization.…”

“…The characteristics of the quasi‐diblocks synthesized in this investigation are summarized in Table . The data are based on analysis by proton nuclear magnetic resonance ( 1 H NMR) and size exclusion chromatography (SEC), as previously described . The samples were collected every hour during the polymerization providing a 23 member PBMA‐ qb ‐PMMA library covering the range of copolymer compositions from 0 to 80 mol% MMA.…”

“…As full conversion was not achieved during the first polymerization step to make the PBMA macroRAFT agent, the residual BMA is incorporated within the PMMA segment of the quasi‐diblock copolymer . The amount of BMA incorporated into the PMMA segment during the second polymerization step was estimated by 1 H NMR.…”

“…The approach detailed here differs from that described in our previous paper in that the samples comprising the library were obtained by systematically withdrawing aliquots of the polymerization mixture as a function of reaction time. Thus, the entire copolymer library was obtained in a “one‐pot” process.…”

RAFT Polymerization – Then and Now

“…High throughput RAFT polymerization in an automated synthesizer has been developed to provide polymer libraries through the synthesis of di-tri-and higher order multi-block copolymers in a 'hands-free' operation (150,151,198,199). Recent work has seen the implementation of freeze-thaw degassing procedures (200) and the application of the methodology to determine RAFT agent activity (52,53,161) and copolymerization reactivity ratios (201).…”