Eur. Phys. J. E (2019) 42: 133
https://doi.org/10.1140/epje/i2019-11897-4

Regular Article

What dielectric spectroscopy can tell us about supramolecular networks^⋆

¹ Department of Chemistry, University of Tennessee, Knoxville, 37996, Knoxville, TN, USA
² Department of Materials Science, University of Tennessee, Knoxville, 37996, Knoxville, TN, USA
³ Oak Ridge National Laboratory, Chemical Sciences Division, 37831, Oak Ridge, TN, USA

^* e-mail: mtress@utk.edu
^** e-mail: sokolov@utk.edu

Received: 2 July 2019
Accepted: 13 September 2019
Published online: 18 October 2019

Abstract

Polymers which can form supramolecular networks are a promising class of materials to provide highly sought-after properties such as self-healing, enhanced mechanical strength, super-stretchability as well as easy recyclability. However, due to the vast range of possible chemical structures it is very demanding to optimize these materials for the desired performance. Consequently, a detailed understanding of the molecular processes that govern the macroscopic properties is paramount to their technological application. Here we discuss some telechelic model systems with hydrogen-bonding end groups and how dielectric spectroscopy in combination with linear oscillatory shear rheology helped to understand the association mechanism on a molecular scale, and verify the model of bond-lifetime renormalization. Furthermore, we analyze a limitation of these H-bonding polymers, namely that there is a trade-off between high plateau modulus and long terminal relaxation time --both cannot be maximized at the same time. Finally, we show how more complex end groups phase separate from the main chain melt and thus lead to a more sophisticated rheological behavior which can overcome that limitation.