Time-dependent rheology of colloidal star glasses

S. A. Rogers, P. T. Callaghan, G. Petekidis, D. Vlassopoulos

Research output: Contribution to journalArticlepeer-review


Suspensions of multiarm star polymers are studied as models for soft colloidal glasses. Using an established pre-shearing protocol which ensures a reproducible initial state (the "rejuvenation" of the system), we report here the time evolution of the stress upon startup of simple shear flow for a range of shear rates. We show the existence of critical shear rates, γ c(c) which are functions of the concentration, c. When the suspensions are sheared at rates below γ c(c), the stress rises to a common value σc(c) which is also a function of the concentration. The system thus develops a yield stress. This behavior manifests itself as an evolution from a monotonic slightly shear-thinning flow curve to a flow curve dominated by a stress plateau. We relate this bulk evolution to spatially resolved velocity profiles. Hence, yield stress is linked to shear banding in this class of soft colloids.

Original languageEnglish (US)
Pages (from-to)133-158
Number of pages26
JournalJournal of Rheology
Issue number1
StatePublished - 2010
Externally publishedYes


  • Aging
  • Colloidal glass
  • Shear banding
  • Star polymer
  • Stress relaxation
  • Stress startup

ASJC Scopus subject areas

  • Materials Science(all)
  • Condensed Matter Physics
  • Mechanics of Materials
  • Mechanical Engineering


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