STRUCTURE EVOLUTION IN A PARAMAGNETIC LATEX SUSPENSION
STRUCTURE EVOLUTION IN A PARAMAGNETIC LATEX SUSPENSION
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DOI：
10.1016/0021-9797(92)90165-i
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发表时间：
1992-12-01
影响因子：
9.9
通讯作者：
GAST, AP
中科院分区：
文献类型：
--
作者：
FERMIGIER, M;GAST, AP
我们提出了超顺磁性乳胶颗粒模型系统的聚集。我们测量非平衡聚集过程的动力学。在低体积分数下，当施加磁场时，颗粒会经历有吸引力的偶极相互作用，并通过平行于施加的场从尖端到尖端聚集而形成线性链。我们发现聚合受到传输限制，并且平均簇大小随着时间的平方根而增加。长程偶极相互作用以这样一种方式改变通量，我们必须推导出一个特征时间尺度来解释聚集偶极子所经历的弹道轨迹。当表面分数高于百分之几时，横向相互作用会改变聚集机制；观察到类似于“拉链”运动的链条的侧向合并。这种现象导致链增厚，形成颗粒纤维，并最终导致链交联。我们提出了对浓缩悬浮液中完全互连的纤维结构的新观察。
We present the aggregation of a model system of superparamagnetic latex particles. We measure the kinetics of the nonequilibrium aggregation process. At low volume fraction, when the magnetic field is applied, particles experience an attractive dipolar interaction and form linear chains by aggregating tip-to-tip parallel to the applied field. We find that the aggregation is transport limited and the mean cluster size increases with the square root of time. The long range dipolar interactions modify the flux in such a way that we must derive a characteristic time scale accounting for the ballistic trajectories experienced by aggregating dipoles. At surface fractions above a few percent, lateral interactions alter the aggregation mechanism; a sideways coalescence of the chains similar to a “zippering” motion is observed. This phenomenon results in a thickening of the chains to create fibers of particles and is eventually responsible for the crosslinking of chains. We present a new observation of a fully interconnected fibrous structure in concentrated suspensions.