基于Mie散射理论的颗粒粒度分布转换

摘要

The intensity-weighted average particle size and intensity-weighted particle size distribution(PSD) can be obtained by the dynamic light scattering.To get the number-weighted PSD or volume-weighted PSD from the intensity-weighted PSD,the intensity scattered by particles of different size must be taken into account.The light intensity scattered by particles of different size is calculated using Mie scattering theory.Then,the number-weighted PSD can be calculated from the intensity-weighted PSD by dividing by the scattering intensity of the particle with the corresponding size.To demonstrate this the intensity-weighted PSD of the mixed polystyrene latex particles is obtained by dynamic light scattering,and the intensity-weighted PSD is converted to number-weighted and volume-weight PSDs using this method.Scanning electron microscopy is used to get the true number-weighted PSD to compare with our results.Comparison of the two number-weighted PSDs shows that accurate numberweighted PSD can be obtained by using approach outlined.%使用动态光散射法可以获得颗粒的光强加权平均粒径,以及光强加权颗粒粒度分布.为获得数量或体积加权颗粒粒度分布,提出从光强分布到数量分布转换的直接比值法.该方法首先依据Mie散射理论求解不同粒径颗粒的散射光强,然后将光强分布与对应颗粒的散射光强进行比对,获得颗粒的数量分布,进而得到颗粒的体积分布.使用动态光散射法测量得到聚苯乙烯乳胶球混合样品的光强分布,利用直接比值法将光强分布转换为数量分布和体积分布,并与扫描电子显微镜测量的数量分布进行了对比,实验数据表明采用直接比值法能够获得准确的数量分布.