title: Orientational ordering and phase behaviour of binary mixtures of hard spheres and hard spherocylinders.
abstract: We study the structure and fluid-phase behaviour of binary mixtures of hard spheres (HSs) and hard spherocylinders (HSCs) in isotropic and nematic states using the NPnAT ensemble Monte Carlo (MC) approach in which the normal component of the pressure tensor is fixed in a system confined between two hard walls. The method allows one to estimate the location of the isotropic-nematic phase transition and to observe the asymmetry in the composition between the coexisting phases, with the expected enhancement of the HSC concentration in the nematic phase. This is in stark contrast with the previously reported MC simulations where a conventional isotropic NPT ensemble was used. We further compare the simulation results with the theoretical predictions of two analytic theories that extend the original Parsons-Lee theory using the one-fluid and the many-fluid approximations [Malijevský et al., J. Chem. Phys. 129, 144504 (2008)]. In the one-fluid version of the theory, the properties of the mixture are related to an effective one-component HS system, while in the many-fluid theory, the components of the mixtures are represented as separate effective HS particles. The comparison reveals that both the one- and the many-fluid approaches provide a reasonably accurate quantitative description of the mixture including the predictions of the isotropic-nematic phase boundary and degree of orientational order of the HSC-HS mixture.
authors.affiliation: Department of Chemical Engineering, Imperial College London, South Kensington Campus, London SW7 2AZ, United Kingdom.
authors.forename: Liang
authors.initials: L
authors.lastname: Wu
authors.affiliation: Department of Physical Chemistry, ICT Prague, 166 28 Praha 6, Czech Republic, and Institute of Chemical Process Fundamentals of ASCR, 16502 Praha 6, Czech Republic.
authors.forename: Alexandr
authors.initials: A
authors.lastname: Malijevský
authors.affiliation: Department of Chemical Engineering, Imperial College London, South Kensington Campus, London SW7 2AZ, United Kingdom.
authors.forename: George
authors.initials: G
authors.lastname: Jackson
authors.affiliation: Department of Chemical Engineering, Imperial College London, South Kensington Campus, London SW7 2AZ, United Kingdom.
authors.forename: Erich A
authors.initials: EA
authors.lastname: Müller
authors.affiliation: School of Chemical Engineering and Analytical Science, The University of Manchester, Sackville Street, Manchester M13 9PL, United Kingdom.
authors.forename: Carlos
authors.initials: C
authors.lastname: Avendaño