TY - JOUR
T1 - Poly(ethylene glycol)s in Semidilute Regime
T2 - Radius of Gyration in the Bulk and Partitioning into a Nanopore
AU - Gurnev, Philip A.
AU - Stanley, Christopher B.
AU - Aksoyoglu, M. Alphan
AU - Hong, Kunlun
AU - Parsegian, V. Adrian
AU - Bezrukov, Sergey M.
N1 - Publisher Copyright:
© 2017 American Chemical Society.
PY - 2017/3/28
Y1 - 2017/3/28
N2 - 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 (Rg) over 1-30 wt %. We observed a small but statistically reliable decrease in Rg 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. 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.
AB - 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 (Rg) over 1-30 wt %. We observed a small but statistically reliable decrease in Rg 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. 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.
UR - http://www.scopus.com/inward/record.url?scp=85016420524&partnerID=8YFLogxK
U2 - 10.1021/acs.macromol.6b02571
DO - 10.1021/acs.macromol.6b02571
M3 - Article
AN - SCOPUS:85016420524
SN - 0024-9297
VL - 50
SP - 2477
EP - 2483
JO - Macromolecules
JF - Macromolecules
IS - 6
ER -