Volume 78, Number 2, April 2007
Article Number 26002
Number of page(s) 6
Section Condensed Matter: Structural, Mechanical and Thermal Properties
Published online 28 March 2007
EPL, 78 (2007) 26002
DOI: 10.1209/0295-5075/78/26002

Reversible gelation and dynamical arrest of dipolar colloids

R. Blaak, M. A. Miller and J.-P. Hansen

University Chemical Laboratory - Lensfield Road, Cambridge CB2 1EW, UK

received 20 October 2006; accepted in final form 5 March 2007; published April 2007
published online 28 March 2007

We use molecular dynamics simulations of a simple model to show that dispersions of slightly elongated colloidal particles with long-range dipolar interactions, like ferrofluids, can form a physical (reversible) gel at low volume fractions. On cooling, the particles first self-assemble into a transient percolating network of cross-linked chains, which, at much lower temperatures, then undergoes a kinetic transition to a dynamically arrested state with broken ergodicity. This transition from a transient to a frozen gel is characterised by dynamical signatures reminiscent of jamming in much denser dispersions.

61.20.Ja - Computer simulation of liquid structure.
82.70.Dd - Colloids.
82.70.Gg - Gels and sols.

© Europhysics Letters Association 2007