Paper Number
SM22
Session
Polymers Solutions, Melts and Blends
Title
Intermolecular hooking in unentangled semidilute polymer solutions under extensional flow
Presentation Date and Time
October 22, 2019 (Tuesday) 2:20
Track / Room
Track 3 / Room 201
Authors
- Young, Charles D. (University of Illinois at Urbana-Champaign, Department of Chemical and Biomolecular Engineering)
- Sing, Charles E. (University of Illinois at Urbana-Champaign, Department of Chemical and Biomolecular Engineering)
Author and Affiliation Lines
Charles D. Young and Charles E. Sing
Department of Chemical and Biomolecular Engineering, University of Illinois at Urbana-Champaign, Urbana, IL 61801
Speaker / Presenter
Young, Charles D.
Text of Abstract
Polymer solution dynamics and rheology are relevant to a wide range of processing methods including printing, coating, and electrospinning. Developing an understanding of the polymer conformational dynamics and the emergent material properties is challenging because of the interplay of hydrodynamic interactions (HI), excluded volume (EV), and topological constraints. This is particularly true when extensional flow is introduced, which strongly deforms the solution from its equilibrium structure. Using a new technique for rapid Brownian dynamics (BD) simulation, we investigate the transient conformational distributions of semidilute polymer solutions under startup and steady state planar extensional flow at concentrations approaching the entanglement concentration. We find that for moderate strain rates (Wi = 0.5-3.0), intermolecular hooks caused by topological constraints form significantly below the entanglement concentration. We characterize the probability of hooks forming at varying molecular weight, concentration, and strain rate. Finally, we quantify the effect of hooking on molecular properties, such as subpopulations in the ensemble average transient stretch and the coexistence of coiled and stretched conformations, as well as the solution stress.