title: Hydrodynamic mobility of an optically trapped colloidal particle near fluid-fluid interfaces.
abstract: Using optical tweezers, we measure the anisotropic hydrodynamic mobility of a colloidal particle by tracking its thermal motion in an optical trap located near fluid-fluid interfaces, namely, liquid-vapor and liquid-liquid interfaces. The method requires no controlled fluid flow, is independent of conservative interactions between particle and interface, and resolves distance dependent friction to within a fraction of the particle radius. Near the liquid-vapor interface, the friction decreases below that in the bulk, corresponding to predictions of a "perfect-slip" surface.
authors.affiliation: Research School of Chemistry, The Australian National University, Canberra ACT 0200, Australia.
authors.forename: G M
authors.initials: GM
authors.lastname: Wang
authors.forename: R
authors.initials: R
authors.lastname: Prabhakar
authors.forename: E M
authors.initials: EM
authors.lastname: Sevick