title: Optical coherence tomography velocimetry in controlled shear flow.
abstract: Doppler-shift optical coherence tomography with infrared light was used to probe the velocity profiles of concentrated solutions of complex fluids with samples experiencing steady-state shear flow. The apparatus is sensitive to a velocity range of 0.7-330 mm/s probing very small volumes of material (quasicylindrical volume elements of 9-μm length and 11-μm radius with 3.4-picoliter volumes) inside a plate-plate rheometer with a total sample volume of ~100-1000 μL. The technique can scan the flow in the plane perpendicular to the shear direction, building up a two-dimensional map of the velocity flow field. The use of a coherence gate with a broad-band infrared source (9-μm coherence length, 1300-nm wavelength) allows opaque specimens, such as concentrated colloidal suspensions (2% w/w) and margarine, to be probed. We observe the phenomena of wall slip (margarine) and shear banding (polyacrylamide, a linear flexible polyelectrolyte) using this technique.
authors.affiliation: Biological Physics, School of Physics and Astronomy, University of Manchester, Oxford Rd., Manchester M139PL, United Kingdom.
authors.forename: M
authors.initials: M
authors.lastname: Harvey
authors.forename: T A
authors.initials: TA
authors.lastname: Waigh
mesh_terms: D000180:Acrylic Resins / Q000737:chemistry; D003102:Colloids / Q000737:chemistry*; D004548:Elasticity; D004573:Electrolytes; D004867:Equipment Design; D005504:Food Analysis / Q000379:methods; D007368:Interferometry / Q000379:methods; D008383:Margarine; D008422:Materials Testing; D055095:Optics and Photonics; D017785:Photons; D010825:Physics / Q000379:methods; D012212:Rheology / Q000379:methods; D013053:Spectrophotometry / Q000379:methods; D014054:Tomography / Q000379:methods*; D014783:Viscosity; D000099166:Polyacrylamides
chemical_list: D000180:Acrylic Resins; D003102:Colloids; D004573:Electrolytes; D008383:Margarine; D000099166:Polyacrylamides