标题： 一种新颖的设置，将空间分辨动态光散射与流变仪耦合，揭示了凝胶启动剪切中的异质流场和非仿射动力学 显示英文标题

标题： A novel setup coupling space-resolved dynamic light scattering and rheometetry unveils the heterogeneous flow field and non-affine dynamics in startup shear of a gel

摘要： 我们介绍了一种新的光散射装置，该装置连接到商用流变仪，流变仪在平行板几何结构下运行。 该装置能够测量微观动力学，区分由于仿射变形和额外机制（如塑性）的贡献。 通过成像光学布局收集样品散射的光，从而能够以空间和时间分辨率探测平均流动速度和微观动力学。 我们通过测量稀释胶体悬浮液在静止状态和剪切状态下的布朗扩散和流动速度，成功测试了该装置。 该装置的潜力在生物凝胶的启动剪切中得到探索。 对于小的剪切变形，$\gamma \le 2\%$，凝胶的流变响应是线性的。 然而，由于时间和空间上不均匀的重排，从变形开始就出现了显著偏离仿射流动的现象，这些重排表现出与粘滑过程相似的有趣特征。 显示英文摘要

摘要： We present a new light scattering setup coupled to a commercial rheometer operated in the plate-plate geometry. The apparatus allows the microscopic dynamics to be measured, discriminating between the contribution due to the affine deformation and additional mechanisms, such as plasticity. Light backscattered by the sample is collected using an imaging optical layout, thereby allowing the average flow velocity and the microscopic dynamics to be probed with both spatial and temporal resolution. We successfully test the setup by measuring the Brownian diffusion and flow velocity of diluted colloidal suspensions, both at rest and under shear. The potentiality of the apparatus are explored in the startup shear of a biogel. For small shear deformations, $\gamma \le 2\%$, the rheological response of the gel is linear. However, striking deviations from affine flow are seen from the very onset of deformation, due to temporally and spatially heterogeneous rearrangements bearing intriguing similarities with a stick-slip process.