吸附边界分层调控受限胶体相分离的动力学
Adsorbing Boundaries Stratify the Kinetics of Confined Colloidal Phase Separation
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中文总结 AI 辅助
本研究通过模拟对比揭示，吸附边界在受限胶体相分离中导致中央与边界区域呈现不同粗化动力学，并提出遭遇控制标度框架解释边界生长。
中文摘要 AI 辅助
在网络形成材料的相分离中，质量输运与力学松弛相互耦合，然而吸附边界如何重塑这种耦合仍不清楚。我们将解析溶剂流体动力学的流体粒子动力学模拟与自由排出的布朗动力学模拟进行对比，研究对象为限制在平行壁之间的吸引性胶体。吸附边界并非均匀地减缓粗化过程，而是将网络分层为空间上不同的动力学区域。在考虑流体动力学的情况下，自相似的中央网络表现出与孔弹性松弛一致的生长规律，即 Lb~t^(1/2)，而吸附区域则遵循有效的 Lw~t^(1/3) 定律。在自由排出动力学中，中央粗化趋近于 t^(1/3)，而边界指数在可及时间内仍随时间变化。方向分辨的位移显示，靠近壁面处壁法向运动受到抑制，侧向迁移率降低。增强壁面吸引力将吸附岛连接成扩展层，同时局部致密相堆积几乎不变。对于岛状域，我们提出一个可检验的遭遇控制标度框架，将边界生长与域几何、尺寸依赖性迁移率以及不断演化的吸附质量联系起来。因此，局部自相似的中央粗化与不同的或非平稳的边界动力学共存，排除了在可及时间内中央和吸附区域存在共同动力学标度长度的可能性；在这两个区域中，生长规律取决于是否解析溶剂流体动力学。
英文摘要
Phase separation in network-forming materials couples mass transport to mechanical relaxation, yet how adsorbing boundaries reshape this coupling remains unclear. We compare fluid-particle-dynamics simulations resolving solvent hydrodynamics with free-draining Brownian dynamics for attractive colloids confined between parallel walls. Adsorbing boundaries do not slow coarsening uniformly but stratify the network into spatially distinct kinetic regimes. With hydrodynamics, the self-similar central network exhibits growth consistent with poroelastic relaxation, Lb~t^(1/2), whereas the adsorbed region follows an effective Lw~t^(1/3) law. In free-draining dynamics, central coarsening approaches t^(1/3), while the boundary exponent remains time dependent over the accessible times. Direction-resolved displacements reveal suppressed wall-normal motion and reduced lateral mobility near the walls. Increasing wall attraction connects adsorbed islands into an extended layer while leaving local dense-phase packing nearly unchanged. For island-like domains, we propose a testable encounter-controlled scaling framework linking boundary growth to domain geometry, size-dependent mobility, and evolving adsorbed mass. Locally self-similar central coarsening thus coexists with distinct or nonstationary boundary kinetics, precluding a common dynamic-scaling length for the central and adsorbed regions over the accessible times; in both regions, the growth law depends on whether solvent hydrodynamics is resolved.
发表机构
- School of Civil Engineering, Sun Yat-Sen University（中山大学土木工程学院）
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