title: Rheology of fluids measured by correlation force spectroscopy.
abstract: We describe a method, correlation force spectrometry (CFS), which characterizes fluids through measurement of the correlations between the thermally stimulated vibrations of two closely spaced micrometer-scale cantilevers in fluid. We discuss a major application: measurement of the rheological properties of fluids at high frequency and high spatial resolution. Use of CFS as a rheometer is validated by comparison between experimental data and finite element modeling of the deterministic ring-down of cantilevers using the known viscosity of fluids. The data can also be accurately fitted using a harmonic oscillator model, which can be used for rapid rheometric measurements after calibration. The method is non-invasive, uses a very small amount of fluid, and has no actively moving parts. It can also be used to analyze the rheology of complex fluids. We use CFS to show that (non-Newtonian) aqueous polyethylene oxide solution can be modeled approximately by incorporating an elastic spring between the cantilevers.
authors.affiliation: Department of Chemical Engineering, Virginia Tech, Blacksburg, Virginia 24060, USA.
authors.forename: Milad
authors.initials: M
authors.lastname: Radiom
authors.forename: Brian
authors.initials: B
authors.lastname: Robbins
authors.forename: Christopher D F
authors.initials: CD
authors.lastname: Honig
authors.forename: John Y
authors.initials: JY
authors.lastname: Walz
authors.forename: Mark R
authors.initials: MR
authors.lastname: Paul
authors.forename: William A
authors.initials: WA
authors.lastname: Ducker