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arXiv · 2601.20741

Star-like microgels vs star polymers: similarities and differences

Tommaso Papetti·Elisa Ballin·Francesco Brasili·Emanuela Zaccarelli
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Abstract

Star-like microgels have recently emerged as a promising class of thermoresponsive soft colloids, that have an internal architecture similar to that of star polymers. Here, we perform extensive monomer-resolved simulations to theoretically establish this analogy. First, we characterize the effective potential between star-like microgels, finding that it is Gaussian for an extended range of distances, in stark contrast to the Hertzian-like one of standard microgels, but almost identical to that of star polymers with a core partially covered by chains. Next, we investigate the ratio between gyration and hydrodynamic radii across the volume-phase transition, showing qualitative agreement with both star polymers and experimental data. Finally, we estimate the bulk modulus, finding star-like microgels significantly softer than standard microgels and comparable to star polymers. The present work thus demonstrates that star-like microgels behave as ultrasoft particles, akin to star polymers, paving the way for their exploration at high concentrations.

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Tommaso Papetti, Elisa Ballin, Francesco Brasili, Emanuela Zaccarelli. 2026-01-28. Star-like microgels vs star polymers: similarities and differences. https://arxiv.org/abs/2601.20741

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