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State and Local Joint Engineering Laboratory for Novel Functional Polymeric Materials, Jiangsu Key Laboratory of Advanced Functional Polymer Design and Application, Suzhou Key Laboratory of Macromolecular Design and Precision Synthesis, College of Chemistry, Chemical Engineering and Materials Science, Soochow University, Suzhou 215123, China
Macromolecules, 2016, 49 (6), pp 2189–2196
Autocatalytic self-sorting in the biomimetic poly(cystamine methacrylamide hydrochloride) (PCysMA) is presented, whose units comprise lysine-mimetic alkylammonium ions and cystine-mimetic alkyl disulfide spacers. The block copolymer with poly(2-hydroxypropylmethacrylamide) was synthesized directly by RAFT in acidic water under visible light irradiation at 25 °C. Disulfide exchange can be initiated by the terminal thiolates as generated by alkalization-induced aminolysis. 65–67% CysMA units sort into hydrophobic polymer disulfides and water-soluble cystamine at pH 10.5. Moreover, intermediate reactions occur in the presence of copper ions, i.e., Cu(II)–NH2 coordination, aminolysis, NH2-to-SH substitution, and cupric-to-cuprous reduction in metal centers, thus autocatalytic self-sorting with essentially 100% conversion at pH 8.8. UV–vis spectroscopy, 1H NMR, atomic absorption spectroscopy, and elemental analysis confirmed this ideal self-sorting. Dynamic light scattering and atomic force microscopy identified supramolecular-to-supracolloidal self-assembly with concomitant release of cystamine molecules and intermediate cuprous complexes. Such a self-sorting underlines an amazing prospect for the use of a single polymer to achieve artificial reaction complexity, hierarchy, and metabolic process, with minimal synthetic efforts.
链接://pubsdc3.acs.org/doi/abs/10.1021/acs.macromol.6b00152