Correlation of polysiloxane molecular structure to shear-thinning power-law exponent using elastohydrodynamic film thickness measurements

Thomas J. Zolper, Paul Shiller, Manfred Jungk, Tobin J. Marks, Yip Wah Chung, Aaron Greco, Gary Doll, Babak Lotfizadeh Dehkordi, Qian Wang

Research output: Contribution to journalArticle

2 Citations (Scopus)


Siloxane-based polymers (polysiloxanes) are susceptible to temporary shear-thinning that manifests as a reduction of elastohydrodynamic film thickness with increasing entrainment speed or effective shear rate. The departure from Newtonian film thickness can be predicted with the power-law exponent ns, an indicator of the severity of shear-thinning in a polymeric fluid that is influenced by the macromolecular structure. In this paper, a combination of extant rheological and tribological models is applied to determine the power-law exponent of several polysiloxanes using film thickness measurements. Film thickness data at several temperatures and slide-to-roll ratios are used to validate the methodology for several siloxane-based polymers with alkyl and aryl branches.

Original languageEnglish
Article number031503
JournalJournal of Tribology
Issue number3
Publication statusPublished - Jul 1 2015



  • Elastohydrodynamic lubrication
  • Fluid film lubrication
  • Rheology
  • Viscosity

ASJC Scopus subject areas

  • Mechanics of Materials
  • Mechanical Engineering
  • Surfaces and Interfaces
  • Surfaces, Coatings and Films

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