光散射聚集速率测定中T矩阵方法的应用

The use of T-matrix method for determining coagulation rate of colloidal particles in light scattering measurement

聚集速率是评估胶体体系特性及稳定性的关键参数,静态光散射和动态光散射则是测量聚集速率的两个重要方法.然而,用静态光散射和动态光散射测量聚集速率时,需要知道有关单粒子和双粒子聚集体光散射特性的数据.为此,通常需要把动、静两种方法结合,才能消去这个数据.以前各种近似理论曾用来解决这个问题,但因粒子尺寸和形状的限制,结果并不理想.而T矩阵方法可以不受粒子大小和形状的限制计算其光散射特性.本工作用T矩阵方法直接计算静态光散射和动态光散射所必须的粒子散射特性,并将该法得到的聚集速率与动静态光散射结合法得到的聚集速率进行了比较,两者结果很接近.本工作为简化静态光散射和动态光散射测量聚集速率,扩展其应用范围开辟了新途径.

The coagulation rate is an important parameter for colloids, which is very useful for evaluating the colloidal stability. Both static light scattering and dynamic light scattering are commonly used methods for measuring the coagulation rate. By using these methods, the light scattering properties of single particles and aggregates of two particles are needed. Therefore, one may need both the static and dynamic light scattering data to avoid the calculation of the relevant scattering properties. Usually, when only static or dynamic light scattering data are available, various approximations are used to solve the problems related to the light scattering properties of particles and aggregates. However, due to the limitation of size and shape of colloidal particles in these approximations, the results were not always satisfactory. Since the T-matrix method can be used to precisely calculate the characteristic of light scattering without approximation of particle size or shape, we use this method in the determination of coagulation rate in static or dynamic light scattering measurement in this study. The comparison of our results with those measured by simultaneous static and dynamic light scattering method confirms that the T-matrix method is suitable for the light scattering measurement of coagulation rate. Therefore, this study simplifies the coagulation rate measurement by light scattering methods and extends their applications.