Dilute aqueous polystyrene suspensions are found to exhibit a novel vapor-liquid condensation. Upon deionization, weakly interacting homogeneous suspensions below a critical particle concentration condense into a concentrated phase with liquidlike order and a dilute vapor phase. This phenomenon strongly suggests net attraction between particles at interparticle separation several times the particle diameter. The present results are understood on the basis of an effective interparticle model potential.

• Received 9 September 1992

DOI:https://doi.org/10.1103/PhysRevLett.69.3778