Coexistence of solid and liquid phases in shear jammed colloidal drops
Coexistence of solid and liquid phases in shear jammed colloidal drops
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DOI：
10.1038/s42005-022-00998-w
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发表时间：
2022-09
影响因子：
5.5
通讯作者：
P. Shah;S. Arora;M. Driscoll
中科院分区：
文献类型：
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作者：
P. Shah;S. Arora;M. Driscoll
复杂流体在高应力下表现出各种奇异的流动行为，例如剪切增稠和剪切堵塞。流变学是表征大部分流体的流动行为的强大工具。然而，该技术在以空间分辨方式探测流体行为的能力方面受到限制。在这里，我们利用高速成像和跌落冲击中的自由表面几何形状来研究胶体悬浮液的流动。在这里，我们报告了由于冲击引起的剪切干扰而观察到的固相和液相共存的情况。除了观察类牛顿扩散和整体剪切干扰之外，我们还观察到这些状态之间的过渡，以扩散液滴中堵塞悬浮液的局部斑块的形式存在。我们捕获了剪切干扰，因为它是通过从冲击点行进的凝固前沿发生的，并表明该前沿的速度是由冲击条件超出剪切增稠转变的距离决定的。
Complex fluids exhibit a variety of exotic flow behaviours under high stresses, such as shear thickening and shear jamming. Rheology is a powerful tool to characterise these flow behaviours over the bulk of the fluid. However, this technique is limited in its ability to probe fluid behaviour in a spatially resolved way. Here, we utilise high-speed imaging and the free-surface geometry in drop impact to study the flow of colloidal suspensions. Here, we report observations of coexisting solid and liquid phases due to shear jamming caused by impact. In addition to observing Newtonian-like spreading and bulk shear jamming, we observe the transition between these regimes in the form of localised patches of jammed suspension in the spreading drop. We capture shear jamming as it occurs via a solidification front travelling from the impact point, and show that the speed of this front is set by how far the impact conditions are beyond the shear thickening transition.