Puertas Antonio M, Fuchs Matthias, Cates Michael E
Group of Complex Fluids Physics, Department of Applied Physics, University of Almeria, 04120 Almeria, Spain.
J Phys Chem B. 2005 Apr 14;109(14):6666-75. doi: 10.1021/jp045595p.
We present simulation results addressing the dynamics of a colloidal system with attractive interactions close to gelation. Our interaction also has a soft, long-range repulsive barrier that suppresses liquid-gas type phase separation at long wavelengths. The new results presented here lend further weight to an intriguing picture emerging from our previous simulation work on the same system. Whereas mode coupling theory (MCT) offers quantitatively good results for the decay of correlators, closer inspection of the dynamics reveals a bimodal population of fast and slow particles with a very long exchange time scale. This population split represents a particular form of dynamic heterogeneity (DH). Although DH is usually associated with activated hopping and/or facilitated dynamics in glasses, the form of DH observed here may be more collective in character and associated with static (i.e., structural) heterogeneity.
我们展示了关于接近凝胶化的具有吸引相互作用的胶体系统动力学的模拟结果。我们的相互作用还具有一个软的、长程排斥势垒，它在长波长下抑制液 - 气型相分离。此处给出的新结果进一步支持了从我们之前对同一系统的模拟工作中浮现出的一个有趣图景。虽然模式耦合理论（MCT）对于关联函数的衰减给出了定量良好的结果，但对动力学的更仔细研究揭示了存在快速和慢速粒子的双峰分布，其交换时间尺度非常长。这种分布分裂代表了动态非均匀性（DH）的一种特殊形式。尽管DH通常与玻璃中的活化跳跃和/或促进动力学相关，但此处观察到的DH形式可能在性质上更具集体性，并且与静态（即结构）非均匀性相关。
