Investigating the Structural Mechanisms of Shear Banding Using Spatially-resolved Flow-SANS
نویسندگان
چکیده
Shear banding is a flow-induced phenomenon observed in a wide variety of materials, including highly entangled polymers, self-assembled surfactants, colloidal suspensions, and pastes. Its rheological and macroscopic signatures have been well-studied for over a decade, yet surprisingly little is known about the underlying microstructural mechanism(s) that give rise to shear banding in soft matter. In this report, we demonstrate the capabilities of a new shear cell for spatially-resolved small angle neutron scattering (SANS) measurements in the flow-gradient (1-2) plane to elucidate the microstructural mechanisms by which shear banding occurs in a model wormlike micellar surfactant solution.
منابع مشابه
The rheology and microstructure of branched micelles under shear
The rheology and shear-induced structures of a series of self-assembled surfactant worm-like micelles (WLMs) with varying levels of branching are measured using rheoand flow-small angle neutron scattering (SANS). The degree of branching in the mixed cationic/anionic surfactant (CTAT/SDBS) WLMs is controlled via the addition of the hydrotropic salt sodium tosylate and verified by cryo-TEM. The l...
متن کاملDynamic response of block copolymer wormlike micelles to shear flow
The flow behavior of giant wormlike micelles consisting of Pb-Peo block copolymers in the vicinity of the isotropic-nematic phase transition concentration is studied. We explain the appearance of shear banding close to this transition by critical slowing down of the rotational diffusion. This is evidenced by a combination of Fourier transform rheology, time-resolved Small Angle Neutron Scatteri...
متن کاملSHEAR BANDING IN WORMLIKE MICELLAR SOLUTIONS Summer School on Neutron Scattering and Reflectometry
Wormlike micelles are an important class of surfactant micellar architectures that find use in applications ranging from consumer products to energy and nanomaterials. Many wormlike micellar systems exhibit a flow instability known as shear banding, characterized by an inhomogeneous flow field. Although many of the proposed mechanisms and theories for shear banding revolve around fluid microstr...
متن کاملSpatially resolved shear distribution in microfluidic chip for studying force transduction mechanisms in cells.
Fluid shear stress has profound effects on cell physiology. Here we present a versatile microfluidic method capable of generating variable magnitudes, gradients, and different modes of shear flow, to study sensory and force transduction mechanisms in cells. The chip allows cell culture under spatially resolved shear flow conditions as well as study of cell response to shear flow in real-time. U...
متن کاملCoarse-grained description of localized inelastic deformation in amorphous metals
The sequence of shear transformation events that lead to a shear band transition in amorphous metals is described by a spatially random coarse-grained model calibrated to obey the thermodynamic scaling relations that govern flow in a real glass. The model demonstrates that shear banding is a consequence of local shear transformation events that self-organize along planes of maximum resolved she...
متن کامل