title: A Landau-de Gennes theory for hard colloidal rods: Defects and tactoids.
abstract: We construct a phenomenological Landau-de Gennes theory for hard colloidal rods by performing an order parameter expansion of the chemical-potential dependent grand potential. By fitting the coefficients to known results of Onsager theory, we are not only able to describe the isotropic-nematic phase transition as function of density, including the well-known density jump, but also the isotropic-nematic planar interface. The resulting theory is applied in calculations of the isotropic core size in a radial hedgehog defect, the density dependence of linear defects of hard rods in square confinement, and the formation of a nematic droplet in an isotropic background.
authors.affiliation: Institute for Theoretical Physics, Center for Extreme Matter and Emergent Phenomena, Utrecht University, Princetonplein 5, 3584 CC Utrecht, The Netherlands.
authors.forename: J C
authors.initials: JC
authors.lastname: Everts
authors.affiliation: FOM Institute AMOLF, Science Park 104, 1098XG Amsterdam, The Netherlands.
authors.forename: M T J J M
authors.initials: MT
authors.lastname: Punter
authors.affiliation: Institute for Theoretical Physics, Center for Extreme Matter and Emergent Phenomena, Utrecht University, Princetonplein 5, 3584 CC Utrecht, The Netherlands.
authors.forename: S
authors.initials: S
authors.lastname: Samin
authors.affiliation: Institute for Theoretical Physics, Center for Extreme Matter and Emergent Phenomena, Utrecht University, Princetonplein 5, 3584 CC Utrecht, The Netherlands.
authors.forename: P
authors.initials: P
authors.lastname: van der Schoot
authors.affiliation: Institute for Theoretical Physics, Center for Extreme Matter and Emergent Phenomena, Utrecht University, Princetonplein 5, 3584 CC Utrecht, The Netherlands.
authors.forename: R
authors.initials: R
authors.lastname: van Roij