低相干动态光散射研究浓悬浮液中布朗运动粒子的扩散特性  

Diffusion Properties of Brownian Particles in Dense Suspensions by Low-Coherence Dynamic Light Scattering

作　　者：夏辉[1] 李富石[1] 陈智全[1] 林旭[1] 肖元元[1] 黄昊[1] 李青林[1] 

机构地区：[1]中南大学物理科学与技术学院,湖南长沙410083

出　　处：《光学学报》2010年第10期3059-3063,共5页Acta Optica Sinica

基　　金：国家自然科学基金(60708014);湖南省自然科学基金(09JJ5003)资助课题

摘　　要：利用低相干动态光散射方法研究了悬浮液中布朗运动颗粒的扩散特性。利用单散射理论,考虑悬浮液的折射率随分数的变化,通过解析检测到的单散射光的光谱得到不同分数悬浮液中颗粒的有效扩散系数。讨论了三种不同粒径颗粒的有效扩散系数随悬浮液体积分数的变化关系。结果表明,浓悬浮液中布朗运动颗粒的扩散特性受到静态结构因子及颗粒间流体动力学相互作用的影响,随体积分数的增加而减小。在0.01～0.2的体积分数范围内,有效扩散系数测量值与采用Percus-Yevick近似和Cohen-de Schepper近似得到的理论值吻合较好。证明了低相干动态光散射法可用来研究不同体积分数的悬浮液中颗粒的扩散特性。A method of low-coherence dynamic light scattering is used to study the diffusion properties of Brownian motion particles in concentrated colloidal suspensions.Based on the single scattering theory,considering the variation of refractive index of suspensions with the volume fraction,the effective diffusion coefficients are obtained by analyzing the single scattering spectra that are measured by using low-coherence dynamic light scattering method.The effective coefficients for three different particles are investigated as a function of volume fractions.As a result,the diffusion properties of Brownian particles are influenced by hydrodynamic interactions and statistical structure factor of particles.The diffusion coefficient decreases with increase of the volume fraction.In the volume fraction range from 0.01 to 0.2,the measured effective diffusion coefficients are in good agreement with the theoretical values by considering the Percus-Yevick and Cohen-de Schepper approximations.It is confirmed that the low-coherence dynamic light scattering technique can be used to measure the diffusion properties of Brownian particles with different volume fractions.

关 键 词：散射 有效扩散系数 低相干动态光散射 体积分数 Percus-Yevick近似 Cohen-de Schepper近似 测量 

分 类 号：O436[机械工程—光学工程]