title: Sliding/rolling phobic droplets along a fiber: measurement of interfacial forces.
abstract: Phobic droplet-fiber systems possess complex geometries, which have made full characterization of such systems difficult. This work has used atomic force microscopy (AFM) to measure droplet-fiber forces for oil droplets on oleophobic fibers over a range of fiber diameters. The work adapted a previous method and a theoretical model developed by the authors for philic droplet-fiber systems. A Bayesian statistical model was also used to account for the influence of surface roughness on the droplet-fiber force. In general, it has been found that the force required to move a liquid droplet along an oleophobic filter fiber will be less than that required to move a droplet along an oleophilic fiber. However, because of the effects of pinning and/or wetting behavior, this difference may be less than would otherwise be expected. Droplets with a greater contact angle (~110°) were observed to roll along the fiber, whereas droplets with a lesser contact angle (<90°) would slide.
authors.affiliation: Fluid Dynamics Research Group, Curtin University, GPO Box U1987, Perth, Western Australia 6845, Australia.
authors.forename: Ryan
authors.initials: R
authors.lastname: Mead-Hunter
authors.forename: Tanja
authors.initials: T
authors.lastname: Bergen
authors.forename: Thomas
authors.initials: T
authors.lastname: Becker
authors.forename: Rebecca A
authors.initials: RA
authors.lastname: O'Leary
authors.forename: Gerhard
authors.initials: G
authors.lastname: Kasper
authors.forename: Benjamin J
authors.initials: BJ
authors.lastname: Mullins