Department of Chemistry, Texas A&M University, College Station, TX 77843-3122, United States.
J Colloid Interface Sci. 2012 Nov 15;386(1):114-20. doi: 10.1016/j.jcis.2012.07.044. Epub 2012 Jul 24.
Isotropic scattering coefficient measurements were made of monodisperse polystyrene lattices of two different diameters of 144 nm and 223 nm and at volume fractions ranging from 0.15 to 0.22, using frequency domain photon migration measurements at wavelengths of 660, 685, 785 and 828 nm. The isotropic scattering coefficient measurements were shown to be sensitive to the changing ionic strength (0.5-4 mM, NaCl equiv.) of the dispersions exhibiting hindered scattering owing to structure at the lowest ionic strength values. Monte Carlo simulations and numerical solution of the Ornstein Zernike equations were used to compute isotropic scattering coefficients for comparison to measured values. The interaction potential was modeled as a hard sphere Yukawa potential and the Hypernetted Chain closure was used to solve the OZ equation. Effective particle charges were found after renormalization of the bare particle charge and used to predict the isotropic scattering coefficient. The model data were found to follow similar trends as experimental measurements. The refractive index of the particles has found to be an important factor for predicting experimental isotropic scattering coefficient values.
采用频域光迁移测量法，在波长为 660、685、785 和 828nm 下，对直径分别为 144nm 和 223nm 的两种不同粒径的单分散聚苯乙烯晶格，在 0.15 至 0.22 的体积分数范围内，进行各向同性散射系数的测量。结果表明，各向同性散射系数的测量对离子强度（0.5-4mM，NaCl 当量）的变化很敏感，由于最低离子强度值下的结构，分散体表现出受阻碍的散射。采用蒙特卡罗模拟和奥恩斯坦-泽尔尼克方程的数值解，计算各向同性散射系数以与测量值进行比较。相互作用势被建模为硬球 Yukawa 势，超网链封闭用于求解 OZ 方程。经过裸粒电荷的重整化，得到有效粒子电荷，并用于预测各向同性散射系数。模型数据与实验测量结果呈现出相似的趋势。发现颗粒的折射率是预测实验各向同性散射系数值的一个重要因素。
