title: Active microrheology of smectic membranes.
abstract: Thin fluid membranes embedded in a bulk fluid of different viscosity are of fundamental interest as experimental realizations of quasi-two-dimensional fluids and as models of biological membranes. We have probed the hydrodynamics of thin fluid membranes by active microrheology using small tracer particles to observe the highly anisotropic flow fields generated around a rigid oscillating post inserted into a freely suspended smectic liquid crystal film that is surrounded by air. In general, at distances more than a few Saffman lengths from the meniscus around the post, the measured velocities are larger than the flow computed by modeling a moving disklike inclusion of finite extent by superposing Levine-MacKintosh response functions for pointlike inclusions in a viscous membrane. The observed discrepancy is attributed to additional coupling of the film with the air below the film that is displaced directly by the shaft of the moving post.
authors.affiliation: Department of Physics, University of Colorado, Boulder, Colorado 80309, USA.|Soft Materials Research Center, University of Colorado, Boulder, Colorado 80309, USA.
authors.forename: Zhiyuan
authors.initials: Z
authors.lastname: Qi
authors.affiliation: Department of Physics, University of Colorado, Boulder, Colorado 80309, USA.|Soft Materials Research Center, University of Colorado, Boulder, Colorado 80309, USA.
authors.forename: Kyle
authors.initials: K
authors.lastname: Ferguson
authors.affiliation: Department of Physics, University of Colorado, Boulder, Colorado 80309, USA.
authors.forename: Yancey
authors.initials: Y
authors.lastname: Sechrest
authors.affiliation: Department of Physics, University of Colorado, Boulder, Colorado 80309, USA.
authors.forename: Tobin
authors.initials: T
authors.lastname: Munsat
authors.affiliation: Department of Physics, University of Colorado, Boulder, Colorado 80309, USA.|Soft 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, University of Colorado, Boulder, Colorado 80309, USA.|Soft 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, University of Colorado, Boulder, Colorado 80309, USA.|Soft 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, University of Colorado, Boulder, Colorado 80309, USA.|Soft Materials Research Center, University of Colorado, Boulder, Colorado 80309, USA.
authors.forename: Noel A
authors.initials: NA
authors.lastname: Clark
authors.affiliation: Department of Physics, California Polytechnic State University, San Luis Obispo, California 93407, USA.
authors.forename: Tatiana
authors.initials: T
authors.lastname: Kuriabova
authors.affiliation: School of Engineering and Department of Physics, Brown University, Providence, Rhode Island 02912, USA.
authors.forename: Thomas R
authors.initials: TR
authors.lastname: Powers