title: Mutual diffusion of inclusions in freely suspended smectic liquid crystal films.
abstract: We study experimentally and theoretically the hydrodynamic interaction of pairs of circular inclusions in two-dimensional, fluid smectic membranes suspended in air. By analyzing their Brownian motion, we find that the radial mutual mobilities of identical inclusions are independent of their size but that the angular coupling becomes strongly size dependent when their radius exceeds a characteristic hydrodynamic length. These observations are described well for arbitrary inclusion separations by a model that generalizes the Levine-MacKintosh theory of point-force response functions and uses a boundary-element approach to calculate the mobility matrix for inclusions of finite extent.
authors.affiliation: Department of Physics and the Liquid Crystal Materials Research Center, University of Colorado, Boulder, Colorado 80309, USA.
authors.forename: Zhiyuan
authors.initials: Z
authors.lastname: Qi
authors.affiliation: Department of Physics and the Liquid Crystal Materials Research Center, University of Colorado, Boulder, Colorado 80309, USA.
authors.forename: Zoom Hoang
authors.initials: ZH
authors.lastname: Nguyen
authors.affiliation: Department of Physics and the Liquid Crystal Materials Research Center, University of Colorado, Boulder, Colorado 80309, USA.
authors.forename: Cheol Soo
authors.initials: CS
authors.lastname: Park
authors.affiliation: Department of Physics and the Liquid Crystal Materials Research Center, University of Colorado, Boulder, Colorado 80309, USA.
authors.forename: Matthew A
authors.initials: MA
authors.lastname: Glaser
authors.affiliation: Department of Physics and the Liquid Crystal Materials Research Center, University of Colorado, Boulder, Colorado 80309, USA.
authors.forename: Joseph E
authors.initials: JE
authors.lastname: Maclennan
authors.affiliation: Department of Physics and the Liquid Crystal Materials Research Center, University of Colorado, Boulder, Colorado 80309, USA.
authors.forename: Noel A
authors.initials: NA
authors.lastname: Clark
authors.affiliation: School of Engineering, Brown University, Providence, Rhode Island 02912, USA.
authors.forename: Tatiana
authors.initials: T
authors.lastname: Kuriabova
authors.affiliation: School of Engineering, Brown University, Providence, Rhode Island 02912, USA and Department of Physics, Brown University, Providence, Rhode Island 02912, USA.
authors.forename: Thomas R
authors.initials: TR
authors.lastname: Powers
mesh_terms: D001713:Biphenyl Compounds / Q000737:chemistry; D004058:Diffusion; D057446:Hydrodynamics; D050866:Liquid Crystals / Q000737:chemistry*; D008567:Membranes, Artificial; D008956:Models, Chemical; D009570:Nitriles / Q000737:chemistry; D012212:Rheology; D012827:Silicone Oils / Q000737:chemistry; D055682:Viscoelastic Substances / Q000737:chemistry
chemical_list: C495061:4'-octyl-4-cyanobiphenyl; D001713:Biphenyl Compounds; D008567:Membranes, Artificial; D009570:Nitriles; D012827:Silicone Oils; D055682:Viscoelastic Substances