Effect of temperature on the structure and dynamics of triblock polyelectrolyte gels

Anand Rahalkar, Guangmin Wei, Ryan Nieuwendaal, Vivek M. Prabhu, Samanvaya Srivastava, Adam E. Levi, Juan J. De Pablo, Matthew V. Tirrell

Research output: Contribution to journalArticlepeer-review

11 Scopus citations

Abstract

Triblock polyelectrolyte gels were characterized by small-angle neutron scattering (SANS) and dynamic light scattering (DLS). The oppositely charged end blocks self-assemble into polyelectrolyte complex cores, while the neutral poly(ethylene oxide) middle block bridges adjacent cores. The size of the polyelectrolyte complex core does not change with temperature. However, the neutral middle block displays a temperature-dependent conformation. The liquid-like order of the complex core within the gel phase leads to stretched bridging chains that approach their unperturbed dimensions with increasing concentration. A stretch ratio for bridging chains was defined as the ratio between stretched and unperturbed dimensions. A further reduction in the chain stretching occurs with increasing temperature due to solvent quality. DLS observes multiple modes consistent with a collective diffusion (fast mode) and diffusion of clusters (slow mode). The dynamics of these clusters are at length scales associated with the SANS excess scattering, but with relaxation time near the crossover frequency observed by mechanical spectroscopy.

Original languageEnglish (US)
Article number163310
JournalJournal of Chemical Physics
Volume149
Issue number16
DOIs
StatePublished - Oct 28 2018
Externally publishedYes

Bibliographical note

Publisher Copyright:
© 2018 U.S. Government.

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