Chiappini Massimiliano, Grelet Eric, Dijkstra Marjolein
Soft Condensed Matter, Debye Institute for Nanomaterials Science, Department of Physics, Utrecht University, Princetonplein 1, Utrecht 3584 CC, The Netherlands.
Centre de Recherche Paul-Pascal, UMR 5031, CNRS & Université de Bordeaux, 115 Avenue Schweitzer, 33600 Pessac, France.
Phys Rev Lett. 2020 Feb 28;124(8):087801. doi: 10.1103/PhysRevLett.124.087801.
Using simulations, we study the diffusion of rodlike guest particles in a smectic environment of rodlike host particles. We find that the dynamics of guest rods across smectic layers changes from a fast nematiclike diffusion to a slow hopping-type dynamics via an intermediate switching regime by varying the length of the guest rods with respect to the smectic layer spacing. We determine the optimal rod length that yields the fastest and the slowest diffusion in a lamellar environment. We show that this behavior can be rationalized by a complex 1D effective periodic potential exhibiting two energy barriers, resulting in a varying preferred mean position of the guest particle in the smectic layer. The interplay of these two barriers controls the dynamics of the guest particles yielding a slow, an intermediate, and a fast diffusion regime depending on the particle length.
通过模拟，我们研究了棒状客体粒子在棒状主体粒子的近晶环境中的扩散。我们发现，通过改变客体棒相对于近晶层间距的长度，客体棒跨近晶层的动力学从快速的向列型扩散转变为缓慢的跳跃型动力学，中间经过一个切换 regime。我们确定了在层状环境中产生最快和最慢扩散的最佳棒长度。我们表明，这种行为可以通过一个复杂的一维有效周期势来合理化，该势表现出两个能垒，导致客体粒子在近晶层中的优先平均位置发生变化。这两个能垒的相互作用控制了客体粒子的动力学，根据粒子长度产生缓慢、中间和快速扩散 regime。
