Individually Addressable Thermo- and Redox-Responsive Block Copolymers by Combining Anionic Polymerization and RAFT Protocols

• Published in: Macromolecular rapid communications. 2014-04, Vol.35 (7), p.708-714
• Main Authors: Schmidt, Bernhard V. K. J., Elbert, Johannes, Barner-Kowollik, Christopher, Gallei, Markus
• Format: Article
• Language: English
• Subjects: Anionic polymerization; Anions - chemical synthesis; Anions - chemistry; Applied sciences; Aqueous solutions; Block copolymers; Chromatography; Copolymers; Exact sciences and technology; ferrocene; Inorganic and organomineral polymers; Lead (metal); Molecular Structure; NMR spectroscopy; Oxidation-Reduction; Particle Size; Physicochemistry of polymers; Polymerization; Polymers - chemical synthesis; Polymers - chemistry; Preparation; RAFT poly­merization; Rafts; redox-responsive; Self assembly; Surface Properties; Temperature; thermo-responsive
• ISSN: 1022-1336; 1521-3927
• DOI: 10.1002/marc.201300870

A novel diblock copolymer consisting of poly(vinylferrocene) (PVFc) and poly(N,N‐diethylacrylamide) (PDEA) is synthesized via a combination of anionic and RAFT polymerization. The use of a novel route to hydroxyl‐end‐functionalized metallopolymers in anionic polymerization and subsequent esterification with a RAFT agent leads to a PVFc macro‐CTA (M¯n = 3800 g mol−1; Đ = 1.17). RAFT polymerization with DEA affords block copolymers as evidenced by 1H NMR spectroscopy as well as size exclusion chromatography (6400 ≤ M¯n≤ 33700 g mol−1; 1.31 ≤ Đ 1.28). Self‐assembly of the amphiphilic block copolymers in aqueous solution leads to micelles as shown via TEM. Importantly, the distinct thermo‐responsive and redox‐responsive character of the blocks is probed via dynamic light scattering and found to be individually and repeatedly addressable. A combination of anionic and RAFT polymerization leads to novel dual‐stimuli‐responsive block copolymers. Amphiphilic poly(vinylferrocene)‐b‐poly(N,N‐diethylacrylamide) is obtained that forms micellar assemblies in water. Owing to the dual‐responsive block copolymer, individually addressable redox‐ and thermo‐responsive micellation is observed.