Water dynamics within nanostructured amphiphilic statistical copolymers from quasielastic neutron scattering

Understanding the properties of water under either soft or hard confinement has been an area of great interest, but nanostructured amphiphilic polymers that provide a secondary confinement have garnered significantly less attention. Here, a series of statistical copolymers of 2-hydroxyethyl acrylate (HEA) and 2-(N-ethylperfluorooctane sulfonamido)ethyl methacrylate (FOSM) are swollen to equilibrium in water to form nanostructured physically cross-linked hydrogels to probe the effect of soft confinement on the dynamics of water. Changing the composition of the copolymer from 10 to 21 mol. % FOSM decreases the average size of the assembled FOSM cross-link, but also the spacing between the cross-links in the hydrogels with the mean distance between the FOSM aggregates decreasing from 3.9 to 2.7 nm. The dynamics of water within the hydrogels were assessed with quasielastic neutron scattering. These hydrogels exhibit superior performance for inhibition of water crystallization on supercooling in comparison to analogous hydrogels with different hydrophilic copolymer chemistries. Despite the lower water crystallinity, the self-diffusion coefficient for these hydrogels from the copolymers of HEA and FOSM decreases precipitously below 260 K, which is a counter to the nearly temperature invariant water dynamics reported previously with an analogous hydrogel [Wiener et al., J. Phys. Chem. B 120, 5543 (2016)] that exhibits nearly temperature invariant dynamics to 220 K. These results point to chemistry dependent dynamics of water that is confined within amphiphilic hydrogels, where the interactions of water with the hydrophilic segments can qualitatively alter the temperature dependent dynamics of water in the supercooled state.

Files

Metadata

Work Title Water dynamics within nanostructured amphiphilic statistical copolymers from quasielastic neutron scattering
Access
Open Access
Creators
  1. Pablo I. Sepulveda-Medina
  2. Madhusudan Tyagi
  3. Chao Wang
  4. Bryan D. Vogt
License In Copyright (Rights Reserved)
Work Type Article
Publisher
  1. Journal of Chemical Physics
Publication Date April 21, 2021
Publisher Identifier (DOI)
  1. https://doi.org/10.1063/5.0045341
Deposited November 15, 2021

Versions

Analytics

Collections

This resource is currently not in any collection.

Work History

Version 1
published

  • Created
  • Added 1042543_1_merged_1616035455-2.pdf
  • Added Creator Pablo I. Sepulveda-Medina
  • Added Creator Madhusudan Tyagi
  • Added Creator Chao Wang
  • Added Creator Bryan D. Vogt
  • Published
  • Updated
  • Updated