Media-Modulated Interchain or Intrachain Coordination of Amphiphilic Block Copolymer Micelles

Inspired by the tunability of coordination mode of natural zinc proteins, this paper describes a new type of polymer micelle, whose coordination mode may be finely tuned simply via adjusting the solution media To this end, a well-defined poly[N-(6-(3,5-di-tert-butyl-2-hydroxybenzylideneamino)hexyl)methacrylamide]-block-poly(2-hydroxyethyl methacrylate) (PDBHMA-b-PHEMA) amphiphilic block copolymer was synthesized via lapid and well-controlled visible light activating RAFT polymerization at 25 degrees C and subsequently directly reated with 3,5-di-tert-butyl-2-hydroxybenzaldehyde H-1 NM R and GPC analyses indicate the intact structure, well-defined molecular weight, and narrow distribution of PDBHHMA(32)-b-PHEMA(120). PDBHHMA(32)-b-PHEMA(120) may self-assembles into small PDBHHMA-core micelles in methanol or large inversed PDBHHMA-shell micelles in chloromethane Cobalt ions coordinate with the functionalities of PDBHHMA A blocks in whole micellar shells or cores The coordination of PDBHHMA units in micellar shells proceeds much more rapidly than in micellar cotes The addition of small amount of DMF may significantly accelerate the coordination process in micellar cores Although this coordination has a negligible effect on the sizes of both types of spherical micelles, coordination in micellar cores leads to a linear increase of light scattering intensity up to a critical feed molar ratio of [Co(2+)0/[DBHHMA](0) = 0 4, whereas coordination in 'medlar shells does not Influence light scattering intensity, even large excess of cobalt ions added, e g, [Co2+](0)/[DBHHMA](0) = 0 7 In micellar cores, cobalt ions tend to coordinate with DBHHMA units in interchain mode, N,N-dimethylformamide (DMF) cosolvent may accelerate this coordination process but increase the tendency of intracham coordination On the contrary, coordination in micellar shells occurs predominantly in intracham mode These media-tunable coordination modes finely tune the stability of micelles in their nonselective good solvent DMF