Edinburgh Research Explorer

Structure, dynamics, and rheology of colloid-polymer mixtures: From liquids to gels

Research output: Contribution to journalArticle

  • M. Laurati
  • G. Petekidis
  • N. Koumakis
  • F. Cardinaux
  • Andrew B Schofield
  • J. M. Brader
  • M. Fuchs
  • S. U. Egelhaaf

Related Edinburgh Organisations

Original languageEnglish
Article number134907
Pages (from-to)134907-1 134907-14
Number of pages14
JournalThe Journal of Chemical Physics
Volume130
Issue number13
DOIs
Publication statusPublished - 7 Apr 2009

Abstract

We investigate the structural, dynamical, and viscoelastic properties of colloid-polymer mixtures at intermediate colloid volume fraction and varying polymer concentrations, thereby tuning the attractive interactions. Within the examined range of polymer concentrations, the samples varied from fluids to gels. In the liquid phase, an increasing correlation length of the density fluctuations when approaching the gelation boundary was observed by static light scattering and microscopy, indicating clustering and formation of space-spanning networks. Simultaneously, the correlation function determined by dynamic light scattering decays completely, indicating the absence of dynamical arrest. Clustering and formation of transient networks when approaching the gelation boundary is supported by significant changes in the viscoelastic properties of the samples. Upon increasing the polymer concentration beyond the gelation boundary, the rheological properties changed qualitatively again, now they are consistent with the formation of colloidal gels. Our experimental results, namely, the location of the gelation boundary as well as the elastic (storage) and viscous (loss) moduli, are compared to different theoretical models. These include consideration of the escape time as well as predictions for the viscoelastic moduli based on scaling relations and mode coupling theories.

    Research areas

  • colloids, elastic moduli, light scattering, liquid structure, mixtures, polymer gels, rheology, viscoelasticity, PHASE-BEHAVIOR, LIGHT-SCATTERING, GLASS-TRANSITION, NONEQUILIBRIUM BEHAVIOR, LINEAR VISCOELASTICITY, ELASTIC PROPERTIES, TRANSIENT GELS, HARD-SPHERES, SUSPENSIONS, MODEL

ID: 1275294