arXivDaily arXiv每日学术速递 周一至周五更新
arXiv 1311.2802cond-mat.soft
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合成胶体聚集体的形态和运动性

Morphology and mobility of synthetic colloidal aggregates

Anastasios D. Melas, Lorenzo Isella, Athanasios G. Konstandopoulos, Yannis Drossinos

摘要:

在连续质量和动量传递体系中,研究了分形聚集体的几何和动力学性质之间的关系。通过簇-簇聚集算法生成合成聚集体。对它们形态特征的分析表明,分形维数是对团簇大尺度结构的描述,而分形前因子是团簇局部结构的指示。对于一个常数的分形维数,前因子也成为一个集群的形状各向异性的指标。通过解拉普拉斯方程确定的分子-聚集体碰撞率计算定向平均聚集体的流体动力学半径。提出了一个集料流体动力学半径与其回转半径和初级颗粒数之间的经验关系式。建议的表达式只依赖于几何量,独立的统计(整体平均)属性,如分形维数和前因子。各种分形聚集体的流体动力学半径的预测是在非常好的协议与其他方法和文献值的预测。还计算了聚集体动态形状因子和DLCA单体流体动力学屏蔽因子。

英文摘要:

The relationship between geometric and dynamic properties of fractal-like aggregates is studied in the continuum mass and momentum-transfer regimes. The synthetic aggregates were generated by a cluster-cluster aggregation algorithm. The analysis of their morphological features suggests that the fractal dimension is a descriptor of a cluster's large-scale structure, whereas the fractal prefactor is a local-structure indicator. For a constant fractal dimension, the prefactor becomes also an indicator of a cluster's shape anisotropy. The hydrodynamic radius of orientationally averaged aggregates was calculated via molecule-aggregate collision rates determined from the solution of a Laplace equation. An empirical expression that relates the aggregate hydrodynamic radius to its radius of gyration and the number of primary particles is proposed. The suggested expression depends only on geometrical quantities, being independent of statistical (ensemble-averaged) properties like the fractal dimension and prefactor. Hydrodynamic radius predictions for a variety of fractal-like aggregates are in very good agreement with predictions of other methods and literature values. Aggregate dynamic shape factors and DLCA individual monomer hydrodynamic shielding factors are also calculated.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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