Activity makes polymer chains into highly mobile bundles: Editor’s Suggestion in Physical Review Letters

05.12.2018

The work of Emanuele Locatelli and colleagues shows the anomalous properties of an active (self-propelled) linear polymer and it was published in Physical Review Letters this November. Due to its novelty and broad interest, it was featured in the Editor's Suggestion section of the journal.

The Physical Review Letter Editor's Suggestion section of November 2018 features an article by Emanuele Locatelli (Computational Physics, University of Vienna), Valentino Bianco (Chemical Physics, Universidad Complutense de Madrid) and Paolo Malgaretti (Max Planck Institute for Intelligent Systems, Stuttgart), in which a model for active linear polymers has been studied: the self-propulsion is coupled with the local conformation of the chain.  By means of computer simulations the authors show that such activity has drastic effects. First, the polymer is found to prefer more compact, globule-like, configurations as activity increases; visually, it packs up like a messy bundle of yarn. On the contrary a passive polymer assume, typically, open conformations, usually name “coil” state. Concurrently, the active polymer becomes more mobile as activity increases, its diffusion coefficient becoming independent of the polymer length. For comparison, a passive polymer is hindered by its own size as its diffusion coefficient is decreasing by increasing the length of the chain. These effects disappear when the coupling between self-propulsion and local conformation is removed. The results of this study open new routes for activity-controlled polymers and, possibly, for a new generation of polymer-based drug carriers.

Globulelike Conformation and Enhanced Diffusion of Active Polymers", Valentino Bianco, Emanuele Locatelli and Paolo Malgaretti, Phys. Rev. Lett, 121, 217802 (2018).

DOI: 10.1103/PhysRevLett.121.217802

Snapshot of a representative conformation for a polymer chain of 1000 units at high activity. (© Emanuele Locatelli)