Colloidal gelation induced by ring polymers

Author(s)
Esmaeel Moghimi, Iurii Chubak, Maria Kaliva, Parvin Kiany, Taihyun Chang, Junyoung Ahn, Nikolaos Patelis, Georgios Sakellariou, Sergei A. Egorov, Dimitris Vlassopoulos, Christos N. Likos
Abstract

We provide unambiguous experimental evidence that ring polymers are stronger depleting agents in colloidal suspensions than their linear counterparts. We use an intermediate volume fraction (φc=0.44) colloidal gel based on the classic poly(methyl methacrylate) (PMMA) hard spheres, in which the polystyrene depletant is either linear or ring of the same molar mass or the same size. We systematically increase the depletant concentration from zero (no attraction) to well above the gelation point and find that in the presence of rings, gels are formed at smaller concentrations and possess a larger storage modulus in comparison to those induced by the linear chains. Consequently, the yield stress is enhanced; however, the yield strain (gel deformability) remains concomitantly unaffected. Our experimental findings are in agreement with theoretical calculations based on effective interaction potentials. Hence, polymer architecture is a powerful entropic tool to tailor the strength of colloidal gels.

Organisation(s)
Computational and Soft Matter Physics, Research Platform Erwin Schrödinger International Institute for Mathematics and Physics
External organisation(s)
Foundation for Research and Technology—Hellas (FORTH), University of Crete, Sorbonne Université, Pohang University of Science and Technology (POSTECH), National & Kapodistrian University of Athens, University of Virginia
Journal
Physical Review Research
Volume
6
No. of pages
13
ISSN
2643-1564
DOI
https://doi.org/10.1103/PhysRevResearch.6.013079
Publication date
01-2024
Peer reviewed
Yes
Austrian Fields of Science 2012
103023 Polymer physics, 104017 Physical chemistry
ASJC Scopus subject areas
General Physics and Astronomy
Portal url
https://ucrisportal.univie.ac.at/en/publications/9e8cd60a-952a-45ba-a710-faf9ffbf1248