Diffusion of Sticky Nanoparticles in a Polymer Melt: Crossover from Suppressed to Enhanced Transport

Bobby Carroll, Vera Bocharova, Jan Michael Y. Carrillo, Alexander Kisliuk, Shiwang Cheng, Umi Yamamoto, Kenneth S. Schweizer, Bobby G. Sumpter, Alexei P. Sokolov

Research output: Contribution to journalArticlepeer-review

Abstract

The self-diffusion of a single large particle in a fluid is usually described by the classic Stokes-Einstein (SE) hydrodynamic relation. However, there are many fluids where the SE prediction for nanoparticles diffusion fails. These systems include diffusion of nanoparticles in porous media, in entangled and unentangled polymer melts and solutions, and protein diffusion in biological environments. A fundamental understanding of the microscopic parameters that govern nanoparticle diffusion is relevant to a wide range of applications. In this work, we present experimental measurements of the tracer diffusion coefficient of small and large nanoparticles that experience strong attractions with unentangled and entangled polymer melt matrices. For the small nanoparticle system, a crossover from suppressed to enhanced diffusion is observed with increasing polymer molecular weight. We interpret these observations based on our theoretical and simulation insights of the preceding article (paper 1) as a result of a crossover from an effective hydrodynamic core-shell to a nonhydrodynamic vehicle mechanism of transport, with the latter strongly dependent on polymer-nanoparticle desorption time. A general zeroth-order qualitative picture for small sticky nanoparticle diffusion in polymer melts is proposed.

Original languageEnglish (US)
Pages (from-to)2268-2275
Number of pages8
JournalMacromolecules
Volume51
Issue number6
DOIs
StatePublished - Mar 27 2018

ASJC Scopus subject areas

  • Organic Chemistry
  • Polymers and Plastics
  • Inorganic Chemistry
  • Materials Chemistry

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