Rojas-Ochoa L F, Romer S, Scheffold F, Schurtenberger P
Department of Physics, University of Fribourg, CH-1700 Fribourg, Switzerland.
Phys Rev E Stat Nonlin Soft Matter Phys. 2002 May;65(5 Pt 1):051403. doi: 10.1103/PhysRevE.65.051403. Epub 2002 May 21.
We have studied the properties of dense colloidal suspensions with a combination of small-angle neutron scattering (SANS) and diffusing wave spectroscopy (DWS). Contrary to single light scattering, DWS provides dynamic information on length scales, from 1 to 100 nm, comparable to SANS. This offers a unique range of accessible length and time scales perfectly suited for the (noninvasive) investigation of highly concentrated systems. By this we obtain valuable information about the structural properties and the short-time diffusion of electrostatically stabilized, but strongly screened, hard-sphere-like colloidal suspensions with volume fractions up to 30%. We furthermore discuss the consequences of local structural ordering on the optical properties, such as optical density and polarization. Quantitative agreement is found when comparing transmission measurements (optical density) with parameter-free numerical calculations based on the structural characterization from SANS.
我们结合小角中子散射（SANS）和扩散波谱学（DWS）研究了致密胶体悬浮液的性质。与单光散射不同，DWS提供了长度尺度从1到100纳米的动态信息，这与SANS相当。这提供了一个独特的可及长度和时间尺度范围，非常适合对高浓度体系进行（非侵入性）研究。通过这种方式，我们获得了关于静电稳定但强屏蔽的类硬球胶体悬浮液（体积分数高达30%）的结构性质和短时间扩散的有价值信息。我们还讨论了局部结构有序对光学性质（如光密度和偏振）的影响。将透射测量（光密度）与基于SANS结构表征的无参数数值计算进行比较时，发现了定量一致性。
