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

Nick Sherck; Thomas Webber; Dennis Robinson Brown; Timothy Keller; Jacob Monroe; Mikayla Barry; Rachel A Segalman; Glenn H Fredrickson; scott shell; Songi Han

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 (R_ee) 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 R_ee indicate aqueous PEO is a semi-flexible polymer in good solvent. The average R_ee 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.

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