Multiscale Rheo-Optical and Scattering Signatures of Deformation-Induced Anisotropy in Aqueous Cellulose Nanocrystal Suspensions under Large-Amplitude Oscillatory Shear

Here, low-shear rheology and linear viscoelasticity are combined with rheo-polarized imaging (Rheo-PI) and rheo-small-angle light scattering (Rheo-SALS) to compare mechanical, optical, and scattering signatures in the same CNC system.

Analysis of the operational low-rate viscosity and the Winter–Chambon criterion separates an empirical viscosity-crossover concentration, <i>C</i>_cross, from the sol–gel transition concentration, <i>C</i>_g. Under fixed-frequency large-amplitude oscillatory shear (LAOS), nonphase-resolved but directly comparable Rheo-PI and Rheo-SALS readouts show that annularly averaged Rheo-PI retardation becomes detectable at lower concentrations and lower strain amplitudes than those required for the appearance of anisotropic X-shaped SALS patterns.