Isotropic-nematic interfaces of hard-rod fluids

Abstract

Within the Onsager theory we study the planar isotropic-nematic interface of fluids of hard rods. We present a method with which interfacial biaxiality can be dealt with efficiently and systematically, and apply it (i) to the pure hard-rod fluid and (ii) to a binary mixture of thin and thick hard rods. In the one-component system we find a surface tension that is lower by 15% than earlier estimates, and monotonic profiles of the density and the uniaxial order parameter. The biaxial order parameter profile is non-monotonic. In the two-component system we find the possibility of non-monotonic density profiles, and a maximum in the surface tension as a function of the pressure.