Title: The connection between shear thinning and biaxial orientation for quasi-ideal rods Show Chinese title

Title: 剪切稀化与准理想棒状物双轴取向之间的关系

Abstract: The complete orientational ordering tensor of quasi-ideal colloidal rods is obtained as a function of shear rate by performing rheo-SANS (rheology with small angle neutron scattering) measurements on isotropic fd-virus suspensions in the two relevant scattering planes, the flow-gradient (1-2) and the flow-vorticity (1-3) plane. Microscopic ordering can be identified as the origin of the observed shear thinning. A qualitative description of the rheological response by Smoluchowski, as well as Doi--Edwards--Kuzuu theory is possible, as we obtain a master curve for different concentrations, scaling the shear rate with the apparent collective rotational diffusion coefficient. However, the observation suggests that the interdependence of ordering and shear thinning at small shear rates is stronger than predicted. The extracted zero-shear viscosity matches the concentration dependence of the self-diffusion of rods in semi-dilute solutions, while the director tilts close towards the flow direction already at very low shear rates. In contrast, we observe a smaller dependence on the shear rate in the overall ordering at high shear rates, as well as an ever-increasing biaxiality. Show Chinese abstract

Abstract: 通过在各向同性fd病毒悬浮液的两个相关散射平面，即流动-梯度（1-2）平面和流动-涡度（1-3）平面进行流变小角中子散射（rheo-SANS）测量，获得了准理想胶体棒的完整取向有序张量作为剪切速率的函数。微观有序可以被识别为观察到的剪切稀化的原因。可以通过Smoluchowski以及Doi-Edwards-Kuzuu理论对流变响应进行定性描述，因为我们得到了不同浓度下的主曲线，将剪切速率与表观集体旋转扩散系数进行缩放。然而，观察结果表明，在低剪切速率下，有序与剪切稀化之间的相互依赖性比预测的更强。提取的零剪切粘度与半稀溶液中棒状物的自扩散浓度依赖性相匹配，而指向器在非常低的剪切速率下就已接近流动方向。相反，在高剪切速率下，整体有序对剪切速率的依赖性较小，并且双轴性持续增加。