2014/06/11 by Andreas Kaiser, A. Kaiser, Hartmut Löwen +1
Biochemistry, Genetics and Molecular Biology · Materials Science · Physics and Astronomy · #Bacterial biofilms and quorum sensing #Chain (unit) #Colloid #Crossover #Exponent #Function (biology) #Micro and Nano Robotics #Non-equilibrium thermodynamics #Polymer #Polymer Surface Interaction Studies #Scaling #Swelling #cond-mat.soft #cond-mat.stat-mech
paper · pdf · doi:10.1063/1.4891095
published as J. Chem. Phys. 141, 044903 (2014) · 7 pages, 5 figures
arxiv created 2014/06/11 · openalex publication_date 2014/07/28 · arxiv updated 2014/07/29 · openalex created_date 2016/06/24 · openalex updated_date 2026/08/05
The equilibrium structure and dynamics of a single polymer chain in a thermal solvent is by now well-understood in terms of scaling laws. Here, we consider a polymer in a bacterial bath, i.e., in a solvent consisting of active particles which bring in nonequilibrium fluctuations. Using computer simulations of a self-avoiding polymer chain in two dimensions which is exposed to a dilute bath of active particles, we show that the Flory-scaling exponent is unaffected by the bath activity provided the chain is very long. Conversely, for shorter chains, there is a nontrivial coupling between the bacteria intruding into the chain which may stiffen and expand the chain in a nonuniversal way. As a function of the molecular weight, the swelling first scales faster than described by the Flory exponent, then an unusual plateau-like behaviour is reached and finally a crossover to the universal Flory behaviour is observed. As a function of bacterial activity, the chain end-to-end distance exhibits a pronounced non-monotonicity. Moreover, the mean-square displacement of the center of mass of the chain shows a ballistic behaviour at intermediate times as induced by the active solvent. Our predictions are verifiable in two-dimensional bacterial suspensions and for colloidal model chains exposed to artificial colloidal microswimmers.