Focal Point Associationof Core-Crystalline Micelleswith an Amphiphilic Corona Block

We report the preparation of star-like supermicelles by the secondary association of triblock comicelles or scarf-like micelles driven by a change in solvency. These building blocks were synthesized by seeded growth in which crystallites of a triblock terpolymer, either PFS₂₇-<i>b</i>-PTDMA₈₁-<i>b</i>-POEGMA₄₅ (to form triblock comicelles) or PFS₆₆-<i>b</i>-PTDMA₈₁-<i>b</i>-POEGMA₄₅ (to form scarf-like micelles), served as seeds for crystallization-driven self-assembly (CDSA). PFS-<i>b</i>-PTDMA unimers were added in the seeded growth step. The corona-forming block PTDMA–POEGMA is amphiphilic and sensitive to polarity changes of the solvents. We sought solvents in which the upper critical solution temperature (UCST, <i>T</i>_UCST) of POEGMA was slightly above room temperature (RT). Examples included 1-decanol and 1-decanol/decane mixtures. Seeded growth proceeded normally in solvents above the UCST of POEGMA. When the solution temperature was lowered below <i>T</i>_UCST, or when the triblock comicelles or scarf-like micelles were transferred to a solvent (e.g., 1-decanol) below its <i>T</i>_UCST, the center blocks associated to form star-like supermicelles. The addition of small amounts of THF to the medium to increase the solvency for POEGMA led to dissociation of the supermicelles. Transfer of the triblock comicelles to 1-pentanol at RT, below the UCST of PTDMA, also led to controlled secondary association to form supermicelles with a different morphology. Seeded growth with PFS₂₅-<i>b</i>-PDMAEMA₁₈₄ unimers led to supermicelles in which the poly­(dimethylaminoethyl methacrylate) corona chains could serve as carriers for gold nanoparticles (AuNPs). These AuNP@supermicelle complexes could serve as recoverable catalysts, for example to catalyze the condensation polymerization of bis­(dimethylsilyl)­benzene and pentanediol. They were highly active catalysts and showed excellent mechanical robustness for recovery and reuse.