We analyze the conformational dynamics and statistical properties of an active polymer model. The polymer is described as a freely jointed bead-rod chain subject to stochastic active force dipoles that act on the suspending solvent where they drive long-ranged fluid flows. Using Langevin simulations of isolated chains in unconfined domains, we show how the coupling of active flows with polymer conformations leads to emergent dynamics. Systems with contractile dipoles behave similarly to passive Brownian chains with enhanced fluctuations due to dipolar flows. In systems with extensile dipoles, however, our simulations uncover an active coil-stretch transition whereby the polymer spontaneously unfolds and stretches out in its own self-induced hydrodynamic flow, and we characterize this transition in terms of a dimensionless activity parameter comparing active dipolar forces to thermal fluctuations. We discuss our findings in the context of the classic coil-stretch transition of passive polymers in extensional flows and complement our simulations with a simple kinetic model for an active trimer.
Download full-text PDF |
Source |
|---|---|
| http://dx.doi.org/10.1103/PhysRevE.105.014608 | DOI Listing |
Publication Analysis
Top Keywords
Similar Publications
Scaling variation in the pinch-off of colloid-polymer mixtures.
J Colloid Interface Sci
December 2024
School of Astronautics, Beihang University, Beijing 100191, China; Aircraft and Propulsion Laboratory, Ningbo Institute of Technology, Beihang University, Ningbo 315100, China. Electronic address:
Hypothesis: The scaling laws of drop pinch-off are known to be affected by drop compositions including dissolved polymers and non-Brownian particles. When the size of the particles is comparable to the characteristic length scale of the polymer network, these particles may interact strongly with the polymer environment, leading to new types of scaling behaviors not reported before.
Experiments: Using high-speed imaging, we experimentally studied the time evolution of the neck diameter h of drops composed of silica nanoparticles dispersed in PEO solution when extruded from a nozzle.
DNA fragmentation in a steady shear flow.
Biomicrofluidics
September 2022
Department of Chemical Engineering and Materials Science, University of Minnesota, Twin Cities, 421 Washington Ave SE, Minneapolis, Minnesota 55455, USA.
We have determined the susceptibility of T4 DNA (166 kilobase pairs, kbp) to fragmentation under steady shear in a cone-and-plate rheometer. After shearing for at least 30 min at a shear rate of , corresponding to a Reynolds number of and a Weissenberg number of , % of the sample is broken into a polydisperse mixture with a number-averaged molecular weight of kbp and a polydispersity index of , as measured by pulsed-field gel electrophoresis (with a 95% confidence interval). The molecular weight distributions observed here from a shear flow are similar to those produced by a (dominantly extensional) sink flow of DNA and are qualitatively different than the midpoint scission observed in simple extensional flow.
View Article and Find Full Text PDFTransition to the viscoelastic regime in the thinning of polymer solutions.
Soft Matter
April 2022
Department of Mechanical Engineering, University of California, Santa Barbara, California 93106, USA.
In this study, we investigate the transition between the Newtonian and the viscoelastic regimes during the pinch-off of droplets of dilute polymer solutions and discuss its link to the coil-stretch transition. The detachment of a drop from a nozzle is associated with the formation of a liquid neck that causes the divergence of the local stress in a vanishingly small region. If the liquid is a polymer solution, this increasing stress progressively unwinds the polymer chains, up to a point where the resulting increase in the viscosity slows down drastically the thinning.
View Article and Find Full Text PDFSelf-induced hydrodynamic coil-stretch transition of active polymers.
Phys Rev E
January 2022
Department of Mechanical and Aerospace Engineering, University of California San Diego, La Jolla, California 92093, USA.
We analyze the conformational dynamics and statistical properties of an active polymer model. The polymer is described as a freely jointed bead-rod chain subject to stochastic active force dipoles that act on the suspending solvent where they drive long-ranged fluid flows. Using Langevin simulations of isolated chains in unconfined domains, we show how the coupling of active flows with polymer conformations leads to emergent dynamics.
View Article and Find Full Text PDFPolymer crystallization under external flow.
Rep Prog Phys
February 2022
National Synchrotron Radiation Laboratory, Anhui Provincial Engineering Laboratory of Advanced Functional Polymer Film, CAS Key Laboratory of Soft Matter Chemistry, University of Science and Technology of China, Hefei 230026, People's Republic of China.
The general aspects of polymer crystallization under external flow, i.e., flow-induced crystallization (FIC) from fundamental theoretical background to multi-scale characterization and modeling results are presented.
View Article and Find Full Text PDFWant AI Summaries of new PubMed Abstracts delivered to your In-box?
Enter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!