Morphological transitions of flexible fibers in viscous flows

Abstract

<h2>Abstract</h2> Here we present the individual dynamics of flexible and Brownian filaments under shear and compression. We use actin filaments as a model system and observe their dynamics in microfluidic flow geometries using fluorescent labeling techniques and microscopic tracking methods. Under shear we characterize successive transitions from tumbling to buckling and finally snake turns as a function of an elasto-viscous number. Under compression we reveal the formation of three dimensional helicoidal structures and characterize their formation. Finally, we attempt at linking the microscopic observations to the macroscopic suspension properties with preliminary measurements of the shear viscosity of dilute suspensions of actin filaments in microfluidic rheometers.