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Title: Poly(ethylene glycol)s in Semidilute Regime: Radius of Gyration in the Bulk and Partitioning into a Nanopore

In this work, using two approaches, small-angle neutron scattering (SANS) from bulk solutions and nanopore conductance-fluctuation analysis, we studied structural and dynamic features of poly(ethylene glycol) (PEG) water/salt solutions in the dilute and semidilute regimes. SANS measurements on PEG 3400 at the zero-average contrast yielded the single chain radius of gyration (R g) over 1–30 wt %. We observed a small but statistically reliable decrease in R g with increasing PEG concentration: at 30 wt % the chain contracts by a factor of 0.94. Analyzing conductance fluctuations of the α-hemolysin nanopore in the mixtures of PEG 200 with PEG 3400, we demonstrated that polymer partitioning into the nanopore is mostly due to PEG 200. Specifically, for a 1:1 wt/wt mixture the smaller polymer dominates to the extent that only about 1/25 of the nanopore volume is taken by the larger polymer. In conclusion, these findings advance our conceptual and quantitative understanding of nanopore polymer partitioning; they also support the main assumptions of the recent “polymers-pushing-polymers” model.
Authors:
ORCiD logo [1] ; ORCiD logo [2] ;  [3] ; ORCiD logo [4] ;  [3] ;  [1]
  1. Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD (United States). Section on Molecular Transport
  2. Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Biology and Soft Matter Division
  3. Univ. of Massachusetts, Amherst, MA (United States). Department of Physics
  4. Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Center for Nanophase Materials Sciences
Publication Date:
Grant/Contract Number:
AC05-00OR22725
Type:
Accepted Manuscript
Journal Name:
Macromolecules
Additional Journal Information:
Journal Volume: 50; Journal Issue: 6; Journal ID: ISSN 0024-9297
Publisher:
American Chemical Society
Research Org:
Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
Sponsoring Org:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22); USDOE Office of Science (SC), Biological and Environmental Research (BER) (SC-23)
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; 59 BASIC BIOLOGICAL SCIENCES
OSTI Identifier:
1424464