Paper Number
PM21 

Session
Polymer Melts: From Molecular Rheology to Processing

Title
Shear and extensional rheology of entangled bulk polymers functionalized with metal-ligand coordination

Presentation Date and Time
October 17, 2018 (Wednesday) 2:20

Track / Room
Track 2 / Plaza I

Authors (Click on name to view author profile)

  1. Zhuge, Flanco (Univeriste catholique de Louvain, Bio and Soft Matter - IMCN)
  2. Costanzo, Salvatore (Univ. of Montpellier)
  3. Parisi, Daniele (FORTH-IESL, Materials Science and Technology-University of Crete)
  4. Shahid, Taisir (Universite catholique de Louvain, Bio- and Soft Matters)
  5. Fustin, Charles-André (Universite catholique de Louvain, Bio- and Soft Matter - IMCN)
  6. Gohy, Jean-François (Universite catholique de Louvain, Bio- and Soft Matter - IMCN)
  7. Vlassopoulos, Dimitris (FORTH-IESL, Materials Science and Technology-University of Crete)
  8. van Ruymbeke, Evelyne (Univeriste catholique de Louvain, Bio and Soft Matter - IMCN)

Author and Affiliation Lines (in printed abstract book)
Flanco Zhuge1, Salvatore Costanzo2, Daniele Parisi3, Taisir Shahid1, Charles-André Fustin1, Jean-François Gohy1, Dimitris Vlassopoulos3, and Evelyne van Ruymbeke1
1Bio and Soft Matter - IMCN, Univeriste catholique de Louvain, Louvain-La-Neuve, Belgium; 2Univ. of Montpellier, Montpellier, France; 3Materials Science and Technology-University of Crete, FORTH-IESL, HERAKLION, Greece

Speaker / Presenter 
Zhuge, Flanco

Text of Abstract
The advent of dynamic metal-ligand (M-L) coordination has emerged as a powerful strategy for the design of various self-assembled materials with stimuli-responsive properties. Among them, reversible polymeric networks obtained by functionalizing flexible polymer chains with M-L coordination are a promising avenue to engineer soft materials with tunable mechanical properties. In this work, we investigate the linear, nonlinear shear and uniaxial extensional viscoelasticity of low-polydispersity (below 1.3) entangled poly (n-butyl acrylate) chains functionalized with terpyridine ligands. Upon self-assembly, the telechelic 4-arm star precursors form model networks with minimum fraction of defects. Most of the chain segments participate in the entangled network, contrary to networks originating from linear chains with metal binding ligands along their backbone, which contain a large proportion of dangling chain ends or loops.
These model systems are therefore perfect to investigate how the dynamics of metallo-supramolecular bulk networks (MSBNs) is affected by both the dissociation kinetics of M-L complexes and the disentanglement process, and how these two mechanisms are coupled. The measurements are performed on a filament stretching and on a strain controlled rotational rheometers equipped with a cone-partitioned plate geometry. In extension the MSBNs show strain hardening at extension rates below their respective terminal relaxation times. Since the transient viscosity of MSBNs is measured at low strain rates, the strain hardening is attributed to the physical crosslinks which comprise M-L coordination. On the other hand, strong shear thinning behavior is observed at similar deformation rates in nonlinear shear flow. By altering the temperature, we systematically vary the relative importance of the M-L complexes, which allows us to determine their specific contribution to the network properties. Moreover, the properties of these systems can be finely tailored with varying the ratio or the nature of metal ions.