Supramolecular Polymer Brushes : Influence of Molecular Weight and Cross-Linking on Linear Viscoelastic Behavior

Copyright © 2020 American Chemical Society..

The origin of unique rheological response in supramolecular brush polymers is investigated using different polymer chemistries (poly(methyl acrylate) (PmA) and poly(ethylene glycol) (PEG)), topologies (linear or star), and molecular weights. A recently developed hydrogen-bonding moiety (1-(6-isocyanatohexyl)-3-(7-oxo-7,8-dihydro-1,8-naphthyridin-2-yl)-urea) (ODIN) was coupled to PmAs and PEGs to form supramolecular brush polymers, the backbone of which is formed by the associated moieties. At low molecular weights of monofunctionalized polymers (both PmA and PEG), the formed brushes are mostly composed of a thick backbone (with very short arms) and are surrounded by other similar brush polymers, which prevent them from diffusing and relaxing. Therefore, the monofunctionalized PmA with a low M n does not show terminal flow even at the highest experimentally studied temperature (or at longest time scales). By increasing the length of the chains, supramolecular brushes with longer arms are obtained. Due to their lower density of thick backbones, these last ones have more space to move and their relaxation is therefore enhanced. In this work, we show that despite similarities between covalent and transient brush polymers, the elastic response in the latter does not originate from the brush entanglements with a large M e (entanglement molecular weight), but it rather stems from the impenetrable rigid backbone and caging effect similar to the one described for hyperstars.

Medienart:

E-Artikel

Erscheinungsjahr:

2020

Erschienen:

2020

Enthalten in:

Zur Gesamtaufnahme - volume:53

Enthalten in:

Macromolecules - 53(2020), 12 vom: 23. Juni, Seite 4810-4820

Sprache:

Englisch

Beteiligte Personen:

Golkaram, Milad [VerfasserIn]
van Ruymbeke, Evelyne [VerfasserIn]
Portale, Giuseppe [VerfasserIn]
Loos, Katja [VerfasserIn]

Links:

Volltext

Themen:

Journal Article

Anmerkungen:

Date Revised 30.06.2020

published: Print-Electronic

Citation Status PubMed-not-MEDLINE

doi:

10.1021/acs.macromol.0c00074

funding:

Förderinstitution / Projekttitel:

PPN (Katalog-ID):

NLM311733638