Dendritic Macromolecules with an Umbrella-Like Stimuli Response

We introduce generation-specific thermoresponsive dendrons that undergo reversible, temperature-triggered conformational changes with an "umbrella-like" conformation. Built from sequence-defined polymer segments via chemoselective iterative coupling, where we could independently control the stimulus response within each generational layer to obviate cooperative behavior. This noncooperative LCST transition enables selective collapse or expansion within individual generational layers. When grafted to gold nanoparticles with distinct thermal transition states, they form tunable umbrella-like architectures that control grafting density, footprint, and peripheral chain coverage. This structural modulation directly impacts the catalytic activity for the reduction of methylene blue in water, where reaction rates are governed by the balance between accessible gold active sites and diffusion through the polymer corona. These dendritic surface-grafted architectures maintained exceptional colloidal stability while preserving high catalytic accessibility, establishing a versatile platform for stimuli-responsive nanomaterials in catalysis, sensing, and biomolecular recognition.