Consecutive living polymerization from cationic to radical: a straightforward yet versatile methodology for the precision synthesis of “cleavable” block copolymers with a hemiacetal ester junction

摘要: In this paper, we provide a straightforward yet versatile methodology via two consecutive living polymerizations, from cationic to radical, synthesize “cleavable” block copolymers whose segment junction is hemiacetal ester (HAE). The key compound α-halophenyl acetic acid [HOOC–CH(Ph)–X: X = halogen] used as hetero-bifunctional initiator: the carboxylic for polymerization (LCP) and carbon–halogen bond metal-catalyzed radical (LRP). efficiently reacted with vinyl ether (e.g., isobutyl ether: IBVE) give an adduct bond, which was reversibly activated suitable mild Lewis (SnBr4) catalyst initiate LCP of IBVE. Thus obtained poly(IBVE) quantitatively retained α-end initiator thus worked macroinitiator LRP methyl methacrylate (MMA) ruthenium catalyst, form HAE-connected (PIBVE-HAE-b-PMMA), can be cleaved under acidic conditions. Their solution-cast films exhibited mostly cylindrical microphase-separated structures, both cleavage removal PIBVE were achieved in one shot, just by immersing film into trifluoroacetic solution n-hexane without distorting integrity cylinder morphology virtually intact, leading nanoporous patterns.