title: Nematic phase transitions in mixtures of thin and thick colloidal rods.
abstract: We report experimental measurements of the phase behavior of mixtures of thin (charged semiflexible fd virus) and thick (fd-PEG, fd virus covalently coated with polyethylene glycol) rods with diameter ratio varying from 3.7 to 1.1. The phase diagrams of the rod mixtures reveal isotropic-nematic, isotropic-nematic-nematic, and nematic-nematic coexisting phases with increasing concentration. In stark contrast to predictions from earlier theoretical work, we observe a nematic-nematic coexistence region bound by a lower critical point. Moreover, we show that a rescaled Onsager-type theory for binary hard-rod mixtures qualitatively describes the observed phase behavior.
authors.affiliation: Martin Fisher School of Physics, Brandeis University, Waltham, Massachusetts 02454, USA.
authors.forename: Kirstin R
authors.initials: KR
authors.lastname: Purdy
authors.forename: Szabolcs
authors.initials: S
authors.lastname: Varga
authors.forename: Amparo
authors.initials: A
authors.lastname: Galindo
authors.forename: George
authors.initials: G
authors.lastname: Jackson
authors.forename: Seth
authors.initials: S
authors.lastname: Fraden
mesh_terms: D017104:Bacteriophage M13 / Q000737:chemistry* / Q000648:ultrastructure*; D003102:Colloids / Q000032:analysis / Q000737:chemistry*; D046911:Macromolecular Substances / Q000032:analysis / Q000737:chemistry; D049329:Nanostructures / Q000032:analysis / Q000737:chemistry* / Q000648:ultrastructure*; D044367:Phase Transition
chemical_list: D003102:Colloids; D046911:Macromolecular Substances