Study of the end-to-end probability distributions of low-molecular weight, aqueous polyethylene oxide solutions using experimental DEER measurements and molecular dynamics simulations

POSTER

Abstract

Low molecular weight, dilute, aqueous polyethylene oxide (PEO) chain end-to-end distance (Ree) probability distributions, P(r), were measured experimentally and calculated from simulation, filling a fundamental gap in the existing literature for one of the most widely used water soluble polymers. The distributions were measured by Double Electron Electron Resonance (DEER) spectroscopy, resolving the full P(r) distribution within the technique’s range of validity (~2-9 nm). The DEER technique uses small spin probes conjugated to the polymer ends. The probes in simulation are observed to hydrophobically aggregate below the range accessible to DEER (<1.5 nm), with the perturbation to the distributions dropping off rapidly with molecular weight. The distributions and their average Ree indicate aqueous PEO is a semi-flexible polymer in good solvent. The average Ree exhibits excluded volume scaling with molecular weight above the Kuhn length (~0.96 nm), which is quantitatively consistent with scattering data from high molecular weight (>10kDa) PEO.

*This work was supported as part of the Center for Materials for Water and Energy Systems (M-WET), an Energy Frontier Research Center funded by the U.S. Department of Energy, Office of Science, Basic Energy Sciences under Award #DE-SC0019272

Presenters

  • Thomas Webber

    • Chemical Engineering, University of California, Santa Barbara

Authors

  • Nick Sherck

    • University of California, Santa Barbara
    • Chemical Engineering, University of California, Santa Barbara

  • Thomas Webber

    • Chemical Engineering, University of California, Santa Barbara

  • Dennis Robinson Brown

    • Chemical Engineering, University of California, Santa Barbara

  • Timothy Keller

    • Chemistry, University of California, Santa Barbara
    • Chemistry and Biochemistry, University of California, Santa Barbara

  • Jacob Monroe

    • Chemical Engineering, University of California, Santa Barbara

  • Mikayla Barry

    • Materials, University of California, Santa Barbara

  • Rachel A Segalman

    • University of California, Santa Barbara
    • Chemical Engineering, University of California, Santa Barbara
    • University of California at Santa Barbara

  • Glenn H Fredrickson

    • University of California, Santa Barbara
    • Chemical Engineering, University of California, Santa Barbara

  • scott shell

    • University of California, Santa Barbara
    • Chemical Engineering, University of California, Santa Barbara

  • Songi Han

    • Chemistry, University of California, Santa Barbara
    • Chemistry and Biochemistry, University of California, Santa Barbara