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

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 fine-tune 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.