title: Magnetomotive nanoparticle transducers for optical rheology of viscoelastic materials.
abstract: The availability of a real-time non-destructive modality to interrogate the mechanical properties of viscoelastic materials would facilitate many new investigations. We introduce a new optical method for measuring elastic properties of samples which employs magnetite nanoparticles as perturbative agents. Magnetic nanoparticles distributed in silicone-based samples are displaced upon probing with a small external magnetic field gradient and depth-resolved optical coherence phase shifts allow for the tracking of scatterers in the sample with nanometer-scale sensitivity. The scatterers undergo underdamped oscillations when the magnetic field is applied step-wise, allowing for the measurement of the natural frequencies of oscillation of the samples. Validation of the measurements is accomplished using a commercial indentation apparatus to determine the elastic moduli of the samples. This real-time non-destructive technique constitutes a novel way of probing the natural frequencies of viscoelastic materials in which magnetic nanoparticles can be introduced.
authors.affiliation: Department of Physics, University of Illinois at Urbana-Champaign, 1110 W. Green St., Urbana, IL 61801, USA.
authors.forename: Vasilica
authors.initials: V
authors.lastname: Crecea
authors.forename: Amy L
authors.initials: AL
authors.lastname: Oldenburg
authors.forename: Xing
authors.initials: X
authors.lastname: Liang
authors.forename: Tyler S
authors.initials: TS
authors.lastname: Ralston
authors.forename: Stephen A
authors.initials: SA
authors.lastname: Boppart
mesh_terms: D017076:Computer-Aided Design; D055119:Elastic Modulus; D004867:Equipment Design; D019544:Equipment Failure Analysis; D008280:Magnetics / Q000295:instrumentation*; D008420:Manufactured Materials / Q000032:analysis*; D008422:Materials Testing / Q000295:instrumentation*; D053758:Nanoparticles / Q000737:chemistry* / Q000528:radiation effects / Q000648:ultrastructure; D036103:Nanotechnology / Q000295:instrumentation*; D012212:Rheology / Q000379:methods*; D014159:Transducers; D014783:Viscosity