title: Coexistence diameter in two-dimensional colloid-polymer mixtures.
abstract: We demonstrate that the law of the rectilinear coexistence diameter in two-dimensional mixtures of nonspherical colloids and nonadsorbing polymers is violated. Upon approach to the critical point, the diameter shows logarithmic singular behavior governed by a term t ln t, with t the relative distance from the critical point. No sign of a term t2beta could be detected, with beta the critical exponent of the order parameter, indicating a very weak or absent Yang-Yang anomaly. Our analysis thus reveals that nonspherical particle shape alone is not sufficient for the formation of a pronounced Yang-Yang anomaly in the critical behavior of fluids.
authors.affiliation: Institut für Theoretische Physik II, Heinrich Heine Universität Düsseldorf, 40225 Düsseldorf, Germany.
authors.forename: R L C
authors.initials: RL
authors.lastname: Vink
authors.forename: H H
authors.initials: HH
authors.lastname: Wensink