Speaker
Description
Active systems, due to the local breaking of equilibrium, allow for phenomena that their equilibrium counterparts cannot attain. For example, polar active polymers, i.e. polymers made of active monomers whose activity is directed as the local tangent to the polymer backbone, display a coil-to-globule-like transition in three dimension, driven by activity. Introducing heterogeneity in the active forces along the backbone considerably affects the polymer substrate. We will discuss three cases: (i) an active-passive diblock, where the position of the block has a strong influence on the polymer, possibly enhancing knot formation[1,2]; (ii) a sinusoidal pattern, where an analytical theory can be worked out for Gaussian polymers[3]; (iii) a dynamic pattern, where active sites are allowed to travel along the chain, mimicking the action of molecular motors[4,5]. We will showcase how each active pattern modifies the conformation and dynamics of the polymers.
References:
[1] Vatin, M., Kundu, S., & Locatelli, E. (2024). Conformation and dynamics of partially active linear polymers. Soft Matter, 20(8), 1892-1904.
[2] Vatin, M., Orlandini, E., & Locatelli, E. (2025). Upsurge of spontaneous knotting in polar diblock active polymers. Physical Review Letters, 134(16), 168301.
[3] Malgaretti, P., & Locatelli, E. (2025). How Spatially Modulated Activity Reshapes Active Polymer Conformations. arXiv preprint arXiv:2512.14478.
[4] Foglino, M., Locatelli, E., Brackley, C. A., Michieletto, D., Likos, C. N., & Marenduzzo, D. (2019). Non-equilibrium effects of molecular motors on polymers. Soft matter, 15(29), 5995-6005.
[5] Vatin, M. Breoni, et al., Active polymers with migrating active sites, in preparation