Divergence of the long-wavelength collective diffusion coefficient in quasi-one- and quasi-two-dimensional colloidal suspensions.
Divergence of the long-wavelength collective diffusion coefficient in quasi-one- and quasi-two-dimensional colloidal suspensions.
复制标题
准一维和准二维胶体悬浮液中长波长集体扩散系数的发散。
DOI：
10.1103/physreve.89.022303
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发表时间：
2013
期刊：
影响因子：
--
通讯作者：
S. Rice
中科院分区：
文献类型：
--
作者：
B. Lin;B. Cui;Xinliang Xu;R. Zangi;H. Diamant;S. Rice
本文报道了准一维（q1 D）和准二维（q2 D）胶体悬浮液中集体粒子位移的短时长波长行为的实验研究结果。我们的结果是通过流体动力学函数H（q）的q → 0行为报告的，该函数将有效集体扩散系数D（e）（q）与静态结构因子S（q）和孤立粒子的自扩散系数D（0）联系起来：H（q）<$D（e）（q）S（q）/D（0）。对于q1 D和q2 D的胶体悬浮液，当q → 0时，H（q）的发散形式为H（q）<$q（-γ）（1.7 < γ < 1.9）.假设S（q）在q → 0时不发散，我们推断D（e）（q）发散。当q → 0时，这种行为与三维H（q）和D（e）（q）的行为在性质上是不同的，并且发散的函数形式与单组分一维和二维流体中的扩散系数的预测不同，而不受定义系统维数的边界条件的影响。我们提供支持的论点，边界条件，定义了一个封闭的系统发挥了非常重要的作用，在确定长波长行为的集体扩散系数从两个来源：（i）准一维和准二维系统中H（q）和D（e）（q）的模拟结果，以及（ii）验证，使用Lin，Rice和Weitz [Phys.Rev.E51，423（1995）]，Bleibel等人的预测，arXiv：1305.3715，当q → 0时，对于被限制在两种流体之间的界面上的单层胶体颗粒，D（e）（q）发散为q（-1）。
We report the results of experimental studies of the short-time-long-wavelength behavior of collective particle displacements in quasi-one-dimensional (q1D) and quasi-two-dimensional (q2D) colloid suspensions. Our results are reported via the q → 0 behavior of the hydrodynamic function H(q) that relates the effective collective diffusion coefficient D(e)(q), with the static structure factor S(q) and the self-diffusion coefficient of isolated particles D(0): H(q) ≡ D(e)(q)S(q)/D(0). We find an apparent divergence of H(q) as q → 0 with the form H(q) ∝ q(-γ) (1.7 < γ < 1.9) for both q1D and q2D colloid suspensions. Given that S(q) does not diverge as q → 0 we infer that D(e)(q) does. This behavior is qualitatively different from that of the three-dimensional H(q) and D(e)(q) as q → 0, and the divergence is of a different functional form from that predicted for the diffusion coefficient in one-component one-dimensional and two-dimensional fluids not subject to boundary conditions that define the dimensionality of the system. We provide support for the contention that the boundary conditions that define a confined system play a very important role in determining the long-wavelength behavior of the collective diffusion coefficient from two sources: (i) the results of simulations of H(q) and D(e)(q) in quasi-1D and quasi-2D systems and (ii) verification, using data from the work of Lin, Rice and Weitz [Phys. Rev. E 51, 423 (1995)], of the prediction by Bleibel et al., arXiv:1305.3715, that D(e)(q) for a monolayer of colloid particles constrained to lie in the interface between two fluids diverges as q(-1) as q → 0.