Shear light scattering of CNT suspensions

Carbon nanotubes are intrinsically optically anisotropic materials, with the polarizability for light much large along the tube axis than that in transvers directions.  Equppied with shear optical microscopy and light scattering, that property could be utilized to analyze the flow-induced structural anisotropy in CNT suspensions under simple shear flow.  For a weakly elastic polymer melt, the data suggest that the semiflexible tubes orient along the direction of flow at low shear stress, with a transition to vorticity alignment above a critical shear stress. For soft viscoelastic domains suspended in a less viscoelastic fluid under shear flow, shear-induced domain structure yields ubiquitous "butterfly" scattering patterns.  

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