Spatially Distributed Rheological Properties in Confined Polymers by Noncontact Shear

Mithun Chowdhury, Yunlong Guo, Yucheng Wang, Weston L. Merling, Jayachandra H. Mangalara, David S. Simmons, Rodney D. Priestley

Research output: Contribution to journalArticlepeer-review

24 Scopus citations

Abstract

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.

Original languageEnglish (US)
Pages (from-to)1229-1234
Number of pages6
JournalJournal of Physical Chemistry Letters
Volume8
Issue number6
DOIs
StatePublished - Mar 16 2017

All Science Journal Classification (ASJC) codes

  • General Materials Science
  • Physical and Theoretical Chemistry

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