Dynamical arrest in attractive colloids: the effect of long-range repulsion

Phys Rev Lett. 2005 May 27;94(20):208301. doi: 10.1103/PhysRevLett.94.208301. Epub 2005 May 23.


We study gelation in suspensions of model colloidal particles with short-ranged attractive and long-ranged repulsive interactions by means of three-dimensional fluorescence confocal microscopy. At low packing fractions, particles form stable equilibrium clusters. Upon increasing the packing fraction the clusters grow in size and become increasingly anisotropic until finally associating into a fully connected network at gelation. We find a surprising order in the gel structure. Analysis of spatial and orientational correlations reveals that the gel is composed of dense chains of particles constructed from face-sharing tetrahedral clusters. Our findings imply that dynamical arrest occurs via cluster growth and association.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Anisotropy
  • Colloids / analysis
  • Colloids / chemistry*
  • Complex Mixtures / analysis
  • Complex Mixtures / chemistry*
  • Crystallization / methods*
  • Gels / analysis
  • Gels / chemistry*
  • Imaging, Three-Dimensional
  • Microscopy, Confocal
  • Microscopy, Fluorescence
  • Models, Chemical*
  • Motion
  • Static Electricity


  • Colloids
  • Complex Mixtures
  • Gels