Jamming Distance Dictates Colloidal Shear Thickening
Jamming Distance Dictates Colloidal Shear Thickening
复制标题
干扰距离决定胶体剪切增稠
DOI：
10.1103/physrevlett.127.158002
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发表时间：
2021
影响因子：
8.6
通讯作者：
Hsiao, Lilian C.
中科院分区：
文献类型：
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作者：
Pradeep, Shravan;Nabizadeh, Mohammad;Jacob, Alan R.;Jamali, Safa;Hsiao, Lilian C.
我们报告的动态接触网络的胶体悬浮液剪切增稠的实验和计算观察。致密的悬浮液由空间稳定的聚（甲基丙烯酸甲酯）胶体组成，其是球对称的并且具有不同的表面粗糙度。共焦流变仪和耗散粒子动力学模拟表明，剪切增稠强度与标度赤字接触数和标度堵塞距离呈指数关系。与光滑胶体相比，经历额外旋转约束的粗糙胶体需要平均少1.5-2个颗粒接触，以便产生相同的颗粒。这是因为表面粗糙度增强了几何摩擦，使得粗糙胶体在堵塞点附近的自由体积不会发生大的变化。不同粗糙度的胶体的可用自由体积与剪切下堵塞时最大近邻数的不足有关。我们的研究结果进一步表明，每个接触的力是不同的颗粒具有不同的形态。
We report experimental and computational observations of dynamic contact networks for colloidal suspensions undergoing shear thickening. The dense suspensions are comprised of sterically stabilized poly(methyl methacrylate) colloids that are spherically symmetric and have varied surface roughness. Confocal rheometry and dissipative particle dynamics simulations show that the shear thickening strengthscales exponentially with the scaled deficit contact number and the scaled jamming distance. Rough colloids, which experience additional rotational constraints, require an average of 1.5–2 fewer particle contacts as compared to smooth colloids, in order to generate the same. This is because the surface roughness enhances geometric friction in such a way that the rough colloids do not experience a large change in the free volume near the jamming point. The available free volume for colloids of different roughness is related to the deficiency from the maximum number of nearest neighbors at jamming under shear. Our results further suggest that the force per contact is different for particles with different morphologies.