Colloidal arrest by capillary forces

Three situations are compared in which capillary forces, arising at a solid-fluid-fluid contact line, can lead to an arrested state. In the first, an isotropic fluid that enters a biphasic isotropic/nematic coexistence is arrested in its phase separation by the presence of colloids. In the second, colloids coating an interface between two fluids can inhibit the Rayleigh-Plateau instability. In the third case, capillary stresses acting at the surface of a droplet of dense colloidal suspension, surrounded by air, can explain the observed bistability between a fluid droplet and a jammed ' granule '. Common features between these problems are emphasized.