Anisotropic ratchet conveyors (ARC) are a type of digital microfluidic system. Unlike electrowetting based systems, ARCs transport droplets through a passive, micro-patterned surface and applied orthogonal vibrations. The mechanics of droplet transport on ARC devices has yet to be as well characterized and understood as on electrowetting systems. In this work, we investigate how the design of the ARC substrate affects the droplet response to vibrations and perform the first characterization of transport velocity on ARC devices. We discovered that the design of the ARC device has a significant effect on both the transport efficiency and velocity of actuated droplets, and that the amplitude of the applied vibration can modulate the velocity of transported droplets. Finally, we show that the movement of droplet edges is not continuous but rather the sum of quantized steps between features of the ARC device. These results provide new insights into the behavior of droplets vibrated on asymmetric surface patterns and will serve as the foundation for the design and development of future lab-on-a-chip systems.

各向异性棘轮输送机（ARC）是一种 数字微流控系统。与基于电润湿的系统不同，ARC通过无源，微图案化的表面并施加正交振动来传输液滴。ARC设备上的液滴传输机制尚未像电润湿系统那样得到充分的表征和理解。在这项工作中，我们研究了ARC基板的设计如何影响液滴对振动的响应，并对ARC装置上的传输速度进行了首次表征。我们发现，ARC设备的设计对驱动液滴的传输效率和速度都具有显着影响，并且所施加的振动幅度可以调节所驱动液滴的速度。最后，我们表明，液滴边缘的移动不是连续的，而是ARC设备特征之间的量化步长之和。这些结果为在非对称表面图案上振动的液滴行为提供了新的见解，并将为未来芯片实验室系统的设计和开发奠定基础。