Tunable attractions directing nonequilibrium states in dispersions of hardrods

The effect of attractive interactions on the phase behavior of colloidal ha rd rods has been studied by the addition of nonadsorbing polymer. In these rod-polymer mixtures, four pathways of phase separation can be distinguishe d: nucleation and growth, spinodal decomposition, aggregation, and gelation . The first three mechanisms give rise to macroscopic phase separation, whe reas for the latter mechanism this is not necessarily the case. The observe d phenomena are explained on the basis of an interplay between the position of both the spinodal line and the glass line, the overall composition of t he sample, and the range of the potential.