Contact criterion for suspensions of smooth and rough colloids
Contact criterion for suspensions of smooth and rough colloids
复制标题
光滑和粗糙胶体悬浮液的接触准则
DOI：
10.1039/d0sm00072h
复制
发表时间：
2020
期刊：
影响因子：
3.4
通讯作者：
Hsiao, Lilian C.
中科院分区：
文献类型：
--
作者：
Pradeep, Shravan;Hsiao, Lilian C.
我们报告了一种获得搜索距离的方法，该搜索距离用于确定光滑和粗糙胶体的稠密悬浮液中的颗粒接触。该方法通过在不确定度分析中对物理上相关的长度标尺求和来工作，并且不需要对表面粗糙度进行详细的量化。我们将空间稳定的荧光聚甲基丙烯酸甲酯胶体悬浮在折射率匹配的溶剂角鲨烯中，以确保坚硬的球状行为。高速离心法用于将光滑和粗糙的胶体包装到它们各自的堵塞点ϕJ。被堵塞的悬浮液随后用已知体积的溶剂稀释到ϕ<；ϕJ。从共聚焦激光扫描显微图像中获得的稀释胶体悬浮液的结构参数被外推到ϕJ，以确定在堵塞时的平均接触数，J。灵敏度分析表明，搜索距离偏离颗粒直径的1%会导致高达10%的变化，在稠密悬浮液(ϕ>；0.5)中，由于第一配位壳层中最近邻的数量增加，接触数分布的误差被放大。
We report a procedure to obtain the search distance used to determine particle contact in dense suspensions of smooth and rough colloids. This method works by summing physically relevant length scales in an uncertainty analysis and does not require detailed quantification of the surface roughness. We suspend sterically stabilized, fluorescent poly(methyl methacrylate) colloids in a refractive index-matched solvent, squalene, in order to ensure hard sphere-like behavior. High speed centrifugation is used to pack smooth and rough colloids to their respective jamming points, ϕJ. The jammed suspensions are subsequently diluted with known volumes of solvent to ϕ < ϕJ. Structural parameters obtained from confocal laser scanning micrographs of the diluted colloidal suspensions are extrapolated to ϕJ to determine the mean contact number at jamming, J. Contact below jamming refers to nearest neighbors at a length scale below which the effects of hydrodynamic or geometric friction come into play. Sensitivity analyses show that a deviation of the search distance by 1% of the particle diameter results in changing by up to 10%, with the error in contact number distribution being magnified in dense suspensions (ϕ > 0.50) due to an increased number of nearest neighbors in the first coordination shell.