论文标题
使用热棘轮机制在磁性微晶状体中实现净运动
Using Thermal Ratchet Mechanism to Achieve Net Motility in Magnetic Microswimmers
论文作者
论文摘要
热棘轮可以从随机波动中提取有用的工作。这在分子尺度（例如运动蛋白）中很常见，并且也已用于实现微流体装置中的方向转运。在这项工作中，我们使用棘轮原理在外部动力的磁胶体中诱导净运动，否则该胶体表现出倒数（来回）运动。实验系统基于由振荡磁场驱动的铁磁微螺旋，在该磁场中，互惠对称性通过不对称的驱动时间刻度破裂。游泳者与数值计算一致，显示出具有增强率的净运动。这类新的微观磁化，磁性的活性胶体可以提供一个有前途的实验平台，以模拟自然世界中的各种活动物质现象。
Thermal ratchets can extract useful work from random fluctuations. This is common in the molecular scale, such as motor proteins, and has also been used to achieve directional transport in microfluidic devices. In this work, we use the ratchet principle to induce net motility in an externally powered magnetic colloid, which otherwise shows reciprocal (back and forth) motion. The experimental system is based on ferromagnetic micro helices driven by oscillating magnetic fields, where the reciprocal symmetry is broken through asymmetric actuation timescales. The swimmers show net motility with an enhanced diffusivity, in agreement with the numerical calculations. This new class of microscale, magnetically powered, active colloids can provide a promising experimental platform to simulate diverse active matter phenomena in the natural world.
