Breakdown and buildup mechanisms of cellulose nanocrystal suspensions under shear and upon relaxation probed by SAXS and SALS

The breakdown and buildup mechanisms in concentrated cellulose nanocrystal (CNC) suspensions under shear during relaxation upon cessation of were accessed by small-angle X-ray light scattering combined with rheometry. dynamic structural changes over nanometer to micrometer lengthscales related the well-known three-regime rheological behavior. In shear-thinning regime I, large liquid crystalline domains progressively fragmented into micrometer-sized tactoids, their cholesteric axis aligned perpendicular flow direction. viscosity plateau II was associated a further disruption submicrometer-sized elongated tactoids oriented along velocity At high rate, III corresponded parallel individual CNCs Upon flow, process occurred through three-step mechanisms: i) fast reassembling nematic-like organization established up lengthscales, ii) slower formation domains, iii) isotropic redistribution.