Flavylium-Containing Stimuli-Responsive RAFT Polymers: Synthesis and Enhanced Stability

Abstract

Flavyliums are abundant naturally occurring, stimuli-responsive cationic chromophores found in anthocyanins that constitute the majority of red and blue pigments found in flora. While synthetic molecular derivatives have been devised to finetune these characteristics, the development of polymeric materials in this regard remains scarce. To address this, a flavylium-based methacrylamide derivative (FlavM-A1) was successfully synthesized, but its radical polymerization proved to be ineffective. To overcome this constraint, a convergent synthetic route for a series of flavylium-containing polymers was developed, employing reversible addition−fragmentation chain transfer (RAFT) polymerization followed by postmodification to install the flavylium chromophore. The flavylium-containing polymers described in this work exhibit improved hydrolytic stability in their flavylium moieties compared to the small-molecule FlavM-A1 while both possess interesting stimuli responsiveness and surfactant-like properties.