Determination of hydrodynamic diameter of small flocs by means of direct movie analysis of Brownian motion
Determination of hydrodynamic diameter of small flocs by means of direct movie analysis of Brownian motion
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DOI：
10.1016/j.colsurfa.2007.03.030
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发表时间：
2007-10-01
影响因子：
5.2
通讯作者：
Adachi, Y.
中科院分区：
文献类型：
--
作者：
Kusaka, Y.;Adachi, Y.
在光学显微镜下对单个胶体颗粒的布朗运动进行直接电影分析以确定流体动力学直径。从布朗运动的轨迹中获得了单个粒子相对于观察时间间隔的均方位移。流体动力学直径是通过根据爱因斯坦关系确定的扩散系数获得的。通过将预测的相对误差与使用三种不同直径的均匀聚苯乙烯乳胶颗粒进行测量获得的误差进行比较，统计上证实了所应用方法的有效性。在处理 501 帧时，确定了变异系数 (CV) 小于 6% 的流体动力学直径。获得的变异系数对应于布朗运动统计预测的变异系数。获得的双峰直径与其他研究人员报道的一致。对于由三个以上初级颗粒组成的絮凝物，CV值略有增加，最高可达7.3%。该增量可归因于从投影图像确定的质心与真实值的偏差。然而，在此精度内，可以确定由最多六个初级颗粒组成的凝结絮凝物的流体动力学直径。发现确定的流体动力学直径明显小于投影中的最大距离，这表明与絮凝物中组成颗粒的数量存在不同的幂律关系。 (C) 2007 Elsevier B.V. 保留所有权利。
Direct movie analysis of the Brownian motion of single colloidal particles under optical microscope was carried out to determine hydrodynamic diameter. Mean squared displacements of individual particle against time interval of observation were obtained from the trace of Brownian motion. The hydrodynamic diameter is obtained via diffusion coefficient determined on the basis of Einstein relation. The validity of the applied method was statistically confirmed by the comparison of predicted relative error with those obtained from the measurement using uniform polystyrene latex particles of three different diameters. Determination of hydrodynamic diameters with coefficients of variation (CV) less than 6% was achieved when processing 501 frames. Achieved coefficients of variation correspond to those statistically predicted for the Brownian motion. Obtained diameter of doublet was consisted with those reported by other researchers. In the case of floes composed with primary particle more than three, the value of CV slightly increases up to 7.3%. This increment can be ascribed to deviation of center of mass determined from projected image from true value. However, within this accuracy the hydrodynamic diameters of coagulated flocs being composed of up to six primary particles were determined. The determined hydrodynamic diameters were found to be significantly smaller than the maximum distances in the projection indicating different power law relation against the number of composing particles in floes. (C) 2007 Elsevier B.V. All rights reserved.