Banchio AJ, Nägele G, Ferrante A
Department of Physics, University of Konstanz, Konstanz, D-78457, Germany
J Colloid Interface Sci. 1998 Dec 15;208(2):487-499. doi: 10.1006/jcis.1998.5835.
We present a theoretical study on the effect of refractive index variations on static and dynamic light scattering in size-polydisperse suspensions of sterically and charge-stabilized colloidal particles with an internal optical structure (core-shell model) and size-dependent refractive indices. The equilibrium microstructure and the short-time dynamics of these optically, size-, and interaction-polydisperse systems are calculated using hypernetted chain and Percus-Yevick integral equation schemes. Our calculations show that, close to an index matching point, the scattered intensity I(k), the measurable structure factor SM(k), and the measurable hydrodynamic function HM(k) become very sensitive to the refractive index contrast with respect to the solvent. For this purpose, various definitions of index matching points are analyzed, and the strong relative enhancement of the incoherent part of the scattered intensity close to the matching points is discussed. For charge-stabilized systems we show that the anomalous behaviour of I(k) and HM(k) in the matching regime of the solvent refractive index can be well described by a simple approximative scheme, which can be easily implemented. Consequences of our study for scattering experiments aimed to determine particle sizes or structural properties of colloidal dispersions are discussed. Copyright 1998 Academic Press.
我们对具有内部光学结构（核壳模型）且折射率与尺寸相关的空间稳定和电荷稳定胶体颗粒的多分散悬浮液中，折射率变化对静态和动态光散射的影响进行了理论研究。使用超网链和珀库斯 - 耶维克积分方程方案计算了这些光学、尺寸和相互作用多分散体系的平衡微观结构和短时间动力学。我们的计算表明，在接近折射率匹配点时，散射强度I(k)、可测量的结构因子SM(k)和可测量的流体动力学函数HM(k)对相对于溶剂的折射率对比度变得非常敏感。为此，分析了折射率匹配点的各种定义，并讨论了在匹配点附近散射强度非相干部分的强烈相对增强。对于电荷稳定体系，我们表明，在溶剂折射率的匹配区域中I(k)和HM(k)的异常行为可以通过一个简单的近似方案很好地描述，该方案易于实现。讨论了我们的研究对旨在确定胶体分散体颗粒尺寸或结构性质的散射实验的影响。版权所有1998年学术出版社。
