Paper Number
SM34 

Session
Polymers Solutions, Melts and Blends

Title
Extensional rheology of ring polystyrene melt and linear/ring polystyrene blends

Presentation Date and Time
October 23, 2019 (Wednesday) 1:30

Track / Room
Track 3 / Room 201

Authors (Click on name to view author profile)

  1. Huang, Qian (Technical University of Denmark, Department of Chemical and Biochemical Engineering)
  2. Ahn, Junyoung (Pohang University of Science and Technology, Department of Chemistry)
  3. Parisi, Daniele (Foundation for Research and Technology Hellas, Institute of Electronic Structure & Laser)
  4. Chang, Taihyun (Pohang University of Science and Technology, Department of Chemistry)
  5. Hassager, Ole (Technical University of Denmark, Department of Chemical and Biochemical Engineering)
  6. Panyukov, Sergey (Russian Academy of Sciences, P. N. Lebedev Physics Institute)
  7. Rubinstein, Michael (Duke University)
  8. Vlassopoulos, Dimitris (FORTH, Institute of Electronic Structure & Laser)

Author and Affiliation Lines (in printed abstract book)
Qian Huang1, Junyoung Ahn2, Daniele Parisi3, Taihyun Chang2, Ole Hassager1, Sergey Panyukov4, Michael Rubinstein5, and Dimitris Vlassopoulos3
1Department of Chemical and Biochemical Engineering, Technical University of Denmark, Kgs. Lyngby 2800, Denmark; 2Department of Chemistry, Pohang University of Science and Technology, Pohang 37673, Republic of Korea; 3Institute of Electronic Structure & Laser, Foundation for Research and Technology Hellas, Heraklion 70013, Greece; 4P. N. Lebedev Physics Institute, Russian Academy of Sciences, Moscow 117924, Russia; 5Duke University, Durham, NC 27708

Speaker / Presenter 
Huang, Qian

Text of Abstract
The state-of-the-art understanding of entangled linear polymers is based on the concept of physical network formation from entanglements. The physical network is characterized by a plateau modulus in linear viscoelastic (LVE) measurements. However, linking the two free ends of a linear polymer, thereafter called a ring polymer, has dramatic consequences. For example, non-concatenated rings have much lower zero-shear-rate viscosity compared to their linear entangled counterparts. A plateau modulus is not observed in LVE measurements for ring polymers [1].

Due to the difficulties in synthesis, which leads to very limited amount of samples, well-defined ring polymers have never been studied in extensional flow. In this work, we present the first results of extensional rheology of a ring polystyrene (PS) melt with the molecular weight 185k (Ring-185k). We show that the ring PS is surprisingly strain hardening in extensional flow, and reaches the same extensional steady state viscosity as its linear counterpart (Lin-185k) when the stretch rate is fast enough. We further present the extensional rheology of blends made of Ring-185k and Lin-185k, with weight fraction of 5%, 20%, and 30% of Ring-185k, respectively. We show that in the transient stress-strain responses, stress overshoot is observed for the samples containing 20% and 30% Ring-185k, while the stress overshoot is not observed for the pure Ring-185k and Lin-185k.

The present results shed light into the fascinating flow properties of polymers without free ends, while they also advance the state-of-the-art in polymer physics. At the same time, they open the route for understanding the response of folded proteins and chromosome territories under strong external fields.

[1] Pasquino et al., ACS Macro Lett. 2013, 2, 874-878