TY - JOUR
T1 - Spatially Distributed Rheological Properties in Confined Polymers by Noncontact Shear
AU - Chowdhury, Mithun
AU - Guo, Yunlong
AU - Wang, Yucheng
AU - Merling, Weston L.
AU - Mangalara, Jayachandra H.
AU - Simmons, David S.
AU - Priestley, Rodney D.
N1 - Publisher Copyright:
© 2017 American Chemical Society.
PY - 2017/3/16
Y1 - 2017/3/16
N2 - When geometrically confined to the nanometer length scale, a condition in which a large portion of the material is in the nanoscale vicinity of interfaces, polymers can show astonishing changes in physical properties. In this investigation, we employ a unique noncontact capillary nanoshearing method to directly probe nanoresolved gradients in the rheological response of ultrathin polymer films as a function of temperature and stress. Results show that ultrathin polymer films, in response to an applied shear stress, exhibit a gradient in molecular mobility and viscosity that originates at the interfaces. We demonstrate, via molecular dynamics simulations, that these gradients in molecular mobility reflect gradients in the average segmental relaxation time and the glass-transition temperature.
AB - When geometrically confined to the nanometer length scale, a condition in which a large portion of the material is in the nanoscale vicinity of interfaces, polymers can show astonishing changes in physical properties. In this investigation, we employ a unique noncontact capillary nanoshearing method to directly probe nanoresolved gradients in the rheological response of ultrathin polymer films as a function of temperature and stress. Results show that ultrathin polymer films, in response to an applied shear stress, exhibit a gradient in molecular mobility and viscosity that originates at the interfaces. We demonstrate, via molecular dynamics simulations, that these gradients in molecular mobility reflect gradients in the average segmental relaxation time and the glass-transition temperature.
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U2 - 10.1021/acs.jpclett.7b00214
DO - 10.1021/acs.jpclett.7b00214
M3 - Article
C2 - 28256842
AN - SCOPUS:85015145578
SN - 1948-7185
VL - 8
SP - 1229
EP - 1234
JO - Journal of Physical Chemistry Letters
JF - Journal of Physical Chemistry Letters
IS - 6
ER -