Dynamical arrest in attractive colloids: the effect of long-range repulsion.
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.
Campbell
Andrew I
AI
School of Chemistry, University of Bristol, Bristol BS8 1TS, United Kingdom.
Anderson
Valerie J
VJ
van Duijneveldt
Jeroen S
JS
Bartlett
Paul
P
D016880:Anisotropy; D003102:Colloids / Q000032:analysis / Q000737:chemistry*; D045424:Complex Mixtures / Q000032:analysis / Q000737:chemistry*; D003460:Crystallization / Q000379:methods*; D005782:Gels / Q000032:analysis / Q000737:chemistry*; D021621:Imaging, Three-Dimensional; D018613:Microscopy, Confocal; D008856:Microscopy, Fluorescence; D008956:Models, Chemical; D009038:Motion; D055672:Static Electricity
D003102:Colloids; D045424:Complex Mixtures; D005782:Gels