Nygård Kim, Buitenhuis Johan, Kagias Matias, Jefimovs Konstantins, Zontone Federico, Chushkin Yuriy
Department of Chemistry and Molecular Biology, University of Gothenburg, SE-41296 Gothenburg, Sweden.
Forschungszentrum Jülich, ICS-3, D-52425 Jülich, Germany.
Phys Rev Lett. 2016 Apr 22;116(16):167801. doi: 10.1103/PhysRevLett.116.167801. Epub 2016 Apr 21.
The collective diffusion of dense fluids in spatial confinement is studied by combining high-energy (21 keV) x-ray photon correlation spectroscopy and small-angle x-ray scattering from colloid-filled microfluidic channels. We find the structural relaxation in confinement to be slower compared to the bulk. The collective dynamics is wave vector dependent, akin to the de Gennes narrowing typically observed in bulk fluids. However, in stark contrast to the bulk, the structure factor and de Gennes narrowing in confinement are anisotropic. These experimental observations are essential in order to develop a microscopic theoretical description of collective diffusion of dense fluids in confined geometries.
通过结合高能（21 keV）X射线光子相关光谱和来自胶体填充微流体通道的小角X射线散射，研究了受限空间中稠密流体的集体扩散。我们发现，与本体相比，受限空间中的结构弛豫更慢。集体动力学与波矢有关，类似于在本体流体中通常观察到的德热纳窄化。然而，与本体形成鲜明对比的是，受限空间中的结构因子和德热纳窄化是各向异性的。为了建立受限几何结构中稠密流体集体扩散的微观理论描述，这些实验观察结果至关重要。
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