Rheology of concentrated bimodal suspensions of nanosilica in PEG
Rheology of concentrated bimodal suspensions of nanosilica in PEG
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DOI：
10.1122/1.4995604
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发表时间：
2017-09-01
影响因子：
3.3
通讯作者：
Foudazi, Reza
中科院分区：
文献类型：
--
作者：
Daneshfar, Zahra;Goharpey, Fatemeh;Foudazi, Reza
在这项工作中，我们调查的线性粘弹性能，屈服，和剪切增稠行为的高浓度双峰悬浮液的纳米二氧化硅在聚（乙二醇）的分子量为400克/摩尔的体积分数，φ，为0.59和0.61和粒度比δ = 3.4。研究的双峰悬浮液有一个可以忽略不计的耗尽吸引力，而他们显示的重入行为。粘弹性响应作为相对于总加载颗粒（R）的大颗粒分数的函数进行了研究。在R = 0.6的双峰样品中观察到归一化弹性模量、类液体行为（无屈服应变和应力）和最低粘度的强烈降低。当小球的相对体积分数超过大球时，系统的弹性模量、屈服应力和粘度增加。结果发现，模式耦合理论和Herschel-Bulkley模型可以预测所研究的双峰悬浮液在phi = 0.61的行为。此外，我们模拟了剪切增稠行为，以确定临界Peclet数的水簇形成，Pe（HC）的发病。双峰悬浮液具有最低的Pe（HC）和最弱的剪切增稠作用。(C)2017流变学学会。
In this work, we investigate the linear viscoelastic properties, yielding, and shear-thickening behaviors of highly concentrated bimodal suspension of nanosilica in poly(ethylene glycol) with a molecular weight of 400 g/mol at volume fractions, phi, of 0.59 and 0.61 and particle size ratio of delta = 3.4. Studied bimodal suspensions have a negligible depletion attraction, whereas they show the re-entrant behavior. The viscoelastic responses are studied as a function of the large particles fraction with respect to total loaded particles (R). A strong reduction in the normalized elastic modulus, liquidlike behavior (no yield strain and stress), and the lowest viscosities are observed in the bimodal sample with R = 0.6. When the relative volume fraction of small spheres exceeds that of large spheres, the elastic modulus, yield stress, and viscosity of the system increase. It was found that the Mode-Coupling theory and the Herschel-Bulkley model can predict the behavior of studied bimodal suspensions at phi = 0.61. Additionally, we have modeled the shear thickening behavior to determine the critical Peclet number for the onset of hydrocluster formation, Pe(HC). The lowest Pe(HC) and the weakest shear thickening are observed for bimodal suspensions with the re-entrant behavior. (C) 2017 The Society of Rheology.