Rheometry and Rheo-Optics of Flexible Non-Brownian Fibers Suspension
Suspensions of flexible microfibers are commonly encountered in paper pulp processing and have been broadly studied in the dilute and concentrated regimes where they commonly flocculate under flow conditions even for low concentrations (<1% wt). These systems have been reported to show shear thinning behavior and the presence of large first normal stress differences. Here, we use polymeric fibers (produced by microfluidic methods) with tailored geometrical and mechanical features achieving high aspect ratio, flexible, concentrated non-Brownian fiber suspensions. We exploit the fibers high aspect ratio and concentration to impart a novel shear thickening behavior that eventually leads to the gelation of the suspension. Such gelation is purely flow-induced and triggered by fibers mechanical interlocking. We report rheological behavior of the suspension over time as a function of concentration, applied shear rate and fiber confinement and we highlight the gelation process by Rheo-Optics. We report also measurements of the yield stress and viscoelasticity of the obtained hydrogels.
2017-09-07, 11:30 - 12:30
Trainer: Antonio Perazzo
Dr. Antonio Perazzo is currently a Postdoctoral Research Associate in the Mechanical and Aerospace Engineering Department at Princeton University under the direction of Prof. Howard A. Stone. He obtained his PhD degree in Chemical Engineering at the University of Naples “Federico II” under the supervision of Prof. Stefano Guido. His research is devoted to organic flow chemistry, Rheology and Rheo-Optical characterization of complex fluids such as emulsion, gels and suspensions. He is currently member of the Society of Rheology and American Physical Society.
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