Riest Jonas, Nägele Gerhard
Forschungszentrum Jülich GmbH, ICS-3 - Soft Condensed Matter, 52425 Jülich, Germany.
Soft Matter. 2015 Dec 28;11(48):9273-80. doi: 10.1039/c5sm02099a.
Dynamic clustering of globular Brownian particles in dispersions exhibiting competing short-range attraction and long-range repulsion (SALR) such as low-salinity protein solutions has gained a lot of interest over the past few years. While the structure of the various cluster phases has been intensely explored, little is known about the dynamics of SALR systems. We present the first systematic theoretical study of short-time diffusion and rheological transport properties of two-Yukawa potential SALR systems in the single-particle dominated dispersed-fluid phase, using semi-analytic methods where the salient hydrodynamic interactions are accounted for. We show that the dynamics has unusual features compared to reference systems with pure repulsion or attraction. Results are discussed for the hydrodynamic function characterizing short-time diffusion that reveals an intermediate-range-order (cluster) peak, self-diffusion and sedimentation coefficients, and high-frequency viscosity. As important applications, we discuss the applicability of two generalized Stokes-Einstein relations, and assess the wavenumber range required for the determination of self-diffusion in a dynamic scattering experiment.
在诸如低盐度蛋白质溶液等呈现出短程吸引和长程排斥（SALR）相互竞争的分散体系中，球状布朗粒子的动态聚集在过去几年引起了广泛关注。尽管对各种团簇相的结构已进行了深入研究，但对于SALR体系的动力学却知之甚少。我们首次使用半解析方法，对单粒子主导的分散流体相中双 Yukawa 势SALR体系的短时扩散和流变输运性质进行了系统的理论研究，其中考虑了显著的流体动力学相互作用。我们表明，与具有纯排斥或吸引作用的参考体系相比，该动力学具有不同寻常的特征。讨论了表征短时扩散的流体动力学函数的结果，该函数揭示了中程有序（团簇）峰、自扩散系数和沉降系数以及高频粘度。作为重要应用，我们讨论了两个广义 Stokes-Einstein 关系的适用性，并评估了在动态散射实验中确定自扩散所需的波数范围。
