Influence of particle shape on the rheological behavior of three-phase non-brownian suspensions
Influence of particle shape on the rheological behavior of three-phase non-brownian suspensions
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DOI：
10.1016/j.colsurfa.2016.03.006
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发表时间：
2016-05-20
影响因子：
5.2
通讯作者：
Willenbacher, Norbert
中科院分区：
文献类型：
--
作者：
Maurath, Johannes;Bitsch, Boris;Willenbacher, Norbert
毛细管悬浮液是三相流体，包含一个固相和两个不混溶的液相，具有独特的质地和流动特性。到目前为止，研究主要集中在等距颗粒上，在这里我们讨论添加第二种不混溶流体如何影响包括各向异性颗粒在内的悬浮液的结构和流动。对不同形状的碳酸钙以及石墨和铝颗粒进行了研究。对于针状和偏三角面体颗粒，屈服应力 sigma(y) 或存储模量 G' 特征没有增加，这是强毛细管力控制的特征，当添加辅助流体时，观察到渗透颗粒网络。相比之下，当将二次流体引入板状颗粒的悬浮液中时，发现 sigma(y) 和 G' 显着增加，并且光学和电子显微镜证实了毛细管悬浮液的样品跨越网络特征的形成。等距颗粒的悬浮液在二次流体的低比例下表现出明显的 sigma(y) 或 G' 最大值，颗粒体积分数 phi(sec)/phi(solid) 接近 0.1-0.2，而悬浮液则表现出明显的最大值。片状颗粒的 sigma(y) 和 G' 值在较宽的 phi(sec)/phi(solid) 值范围内表现出恒定的 sigma(y) 和 G' 值，直至接近 1，直到发生球形团聚。由于毛细管桥的形状不同，板状颗粒的悬浮液可以容纳比包含球形颗粒的系统大得多的二次流体，直到形成球形团聚，从而为复杂的多组分糊状产品的设计提供了通用的基本概念。 (C) 2016 Elsevier B.V. 保留所有权利。
Capillary suspensions are three-phase fluids comprising a solid and two immiscible, liquid phases with unique texture and flow properties. So far, research focused on isometric particles, here we discuss how the addition of a second, immiscible fluid affects structure and flow of suspensions including anisotropic particles. Differently shaped calcium carbonate as well as graphite and aluminum particles have been investigated.For needle-shaped and scalenohedral particles no increase in yield stress sigma(y) or storage modulus G' characteristic for a strong capillary force controlled, percolating particle network is observed when a secondary fluid is added. In contrast, a pronounced increase in sigma(y) and G' is found when a secondary fluid is introduced to suspensions of plate-like particles and optical as well as electron microscopy confirm the formation of a sample-spanning network characteristic for capillary suspensions.Suspensions of isometric particles exhibit a distinct maximum in sigma(y) or G' at low fractions of secondary fluid to particle volume fraction phi(sec)/phi(solid) approximate to 0.1-0.2, whereas suspensions of plate-like particles exhibit constant sigma(y) and G' values over a wide range of phi(sec)/phi(solid) values up to approximate to 1 until spherical agglomeration occurs. Due to the different shape of the capillary bridges suspensions of plate-like particles can accommodate much larger fractions of secondary fluid until spherical agglomeration sets in than systems including spherical particles thus offering a versatile basic concept for the design of complex multi-component paste-like products. (C) 2016 Elsevier B.V. All rights reserved.