Synthesis of branched catechol-containing polymers by cationic polymerization of unprotected 4-vinylcatechol: Combination of vinyl polymerization and polyaddition

Abstract In this study, we demonstrate a protection-free synthetic strategy for branched catechol-containing polymers using 4-vinylcatechol (4VC) as an AB₂-type monomer. 4VC was found to polymerize through simultaneous vinyl cationic polymerization and electrophilic polyaddition, which undergo via identical carbocations as the intermediates. The polymerization of 4VC with various acid catalysts confirmed the formation of branched poly(4VC) structures through dual polymerization pathways. The copolymerization of 4VC with 2-hydroxyethyl vinyl ether (HEVE) also revealed distinct reactivity under protic acid catalysis. The resulting polymers exhibited high thermal resistance and maintained strong metal adhesion, highlighting the impact of branched architecture on material performance. Graphical Abstract