Details

Autor(en) / Beteiligte

• Andreu, Jordi S.
• Camacho, Juan
• Faraudo, Jordi

Titel

Aggregation of superparamagnetic colloids in magnetic fields: the quest for the equilibrium state

Ist Teil von

• Soft matter, 2011-01, Vol.7 (6), p.2336-2339

Erscheinungsjahr

2011

Quelle

Alma/SFX Local Collection

Beschreibungen/Notizen

• Previous experimental and simulation studies of superparamagnetic colloids in a strong external field have systematically shown a nonequilibrium aggregation process in which chains of particles steadily grow in the direction of the applied external field with the average length increasing as a power law over time. Here we show, by employing Langevin dynamics simulations, the existence of a different behavior under the effects of an external magnetic field: after a transient period of chain formation, the system attains an equilibrium state. Furthermore, a thermodynamic self-assembly theory supports the simulation results and it also predicts that the average chain length in the equilibrium state depends only on a dimensionless parameter combining the volume fraction of colloids [curly or open phi]0 and the magnetic coupling parameter [Gamma]. The conditions under which this new behavior can be observed are discussed here.