Radtke Matthias, Netz Roland R
Department of Physics, Freie Universität Berlin, Arnimallee 14, 14195, Berlin, Germany.
Eur Phys J E Soft Matter. 2016 Nov;39(11):116. doi: 10.1140/epje/i2016-16116-4. Epub 2016 Nov 30.
The motion of a single rigid or elastic particle inside a corrugated narrow channel is investigated by means of Brownian dynamics simulations. Periodic oscillations of one of the asymmetric channel surfaces induce directed particle transport. For different surface structures of the resting channel surface, we determine optimal transport properties in terms of the driving frequency, particle size, and corrugation amplitude. The transport direction is changed when switching from perpendicular motion of the oscillating surface to parallel motion with respect to the resting surface, which can be rationalized by a transition from a flashing to a pushing ratchet effect. We also study the diffusion behavior and find strongly enhanced diffusion for parallel oscillatory motion with a diffusivity significantly larger than for free diffusion. Elastic large particles exhibit suppressed transport with increasing rigidity. In contrast, for small particles, increasing rigidity enhances the particle transport both in terms of particle velocity and diffusivity.
通过布朗动力学模拟研究了单个刚性或弹性粒子在波纹状狭窄通道内的运动。不对称通道表面之一的周期性振荡会引发粒子的定向输运。对于静止通道表面的不同结构，我们根据驱动频率、粒子尺寸和波纹幅度确定了最佳输运特性。当振荡表面从垂直运动切换为相对于静止表面的平行运动时，输运方向会发生改变，这可以通过从闪烁棘轮效应到推动棘轮效应的转变来解释。我们还研究了扩散行为，发现平行振荡运动时扩散显著增强，其扩散系数明显大于自由扩散时的扩散系数。随着刚性增加，弹性大粒子的输运会受到抑制。相反，对于小粒子，增加刚性在粒子速度和扩散系数方面都会增强粒子输运。
