论文标题
剪切堵塞和脆弱性在细胞下的分形悬浮液中
Shear jamming and fragility in fractal suspensions under confinement
论文作者
论文摘要
在施加的应力下，许多密集的颗粒悬浮液的粘度急剧增加，这种响应被称为不连续的缩短颗粒（DST）。在某些情况下，施加的应力甚至可以将悬浮液转化为固体样剪切状态。尽管已经对剪切干扰（SJ）进行了探测，该密集的悬浮液的颗粒具有明确的形状，但尚未探索这种分形物体的现象。在这里，使用流变学和原位光学成像，我们研究了限制下多壁碳纳米管（MWCNT）的超稀释分形悬浮液的流动行为。我们显示了从流动到SJ状态的直接过渡，而没有前质量DST在分形悬浮液中以发作量的分数，$ ϕ \ sim $ 0.5 \％，大大低于常规密集悬浮液（$ ϕ \ sim $ 55 \％）。超低浓度使我们能够证明SJ状态的脆弱性和相关接触动力学，这些趋势仍未在悬浮液中进行实验探索。此外，使用广义的Wyart-Cates模型，我们为分形悬浮液提出了一个通用相图，以捕获SJ在较大的剪切应力和体积分数范围内没有先前DST的可能性。
Under applied stress, the viscosity of many dense particulate suspensions increases drastically, a response known as discontinuous shear-thickening (DST). In some cases, the applied stress can even transform the suspension into a solid-like shear jammed state. Although shear jamming (SJ) has been probed for dense suspensions with particles having well-defined shapes, such a phenomenon for fractal objects has not been explored. Here, using rheology and in situ optical imaging, we study the flow behaviour of ultra-dilute fractal suspensions of multi-walled carbon nanotubes (MWCNT) under confinement. We show a direct transition from flowing to SJ state without a precursory DST in fractal suspensions at an onset volume fraction, $ϕ\sim$ 0.5\%, significantly lower than that of conventional dense suspensions ($ϕ\sim$ 55\%). The ultra-low concentration enables us to demonstrate the fragility and associated contact dynamics of the SJ state, which remain experimentally unexplored in suspensions. Furthermore, using a generalized Wyart-Cates model, we propose a generic phase diagram for fractal suspensions that captures the possibility of SJ without prior DST over a wide range of shear stress and volume fractions.
