Selective Activation of Dynamics in Kinetically FrozenSupramolecular Polymer Bottlebrush Assemblies

Supramolecular assemblies are typically characterized by their dynamic nature due to the comparable weak non-covalent interactions. While these properties confer adaptability, stability issues may limit application in areas such as drug delivery or tissue engineering. Here, supramolecular assemblies of amphiphilic polymers containing benzenetrispeptide and benzenetrisureas motifs are inherently stable and non-dynamic at ambient conditions is shown, but dynamic exchange can be selectively activated. Stimulated emission depletion microscopy combined with automated image analysis revealed no dynamic exchange between complementary labeled fibers independent of the length of the hydrophobic domains at ambient conditions in pure water for several days. Competitive solvent addition facilitates dynamic exchange but compromises stability. Raising the temperature of the samples in pure water to 60 °C, however, induces similar dynamics while fiber stability is maintained. The amphiphilic character, in combination with the strong hydrogen bonds, seems to endow these supramolecular polymer brushes with unique switchable dynamics.