van Baalen Carolina, Ketzetzi Stefania, Tintor Anushka, Gabay Israel, Isa Lucio
Laboratory for Soft Materials and Interfaces, Department of Materials, ETH Zürich, Vladimir-Prelog-Weg 5, 8093 Zürich, Switzerland.
Faculty of Mechanical Engineering, Technion - Israel Institute of Technology, Haifa 3200003, Israel.
Soft Matter. 2025 May 14;21(19):3850-3858. doi: 10.1039/d4sm01512f.
Active colloidal particles typically exhibit a pronounced affinity for accumulating and being captured at boundaries. Here, we engineer long-range repulsive interactions between colloids that self-propel under an electric field and patterned obstacles. As a result of these interactions, particles turn away from obstacles and avoid accumulation. We show that by tuning the applied field frequency, we precisely and rapidly control the effective size of the obstacles and therefore modulate the particle approach distance. This feature allows us to achieve gating and tunable confinement of our active particles whereby they can access regions between obstacles depending on the applied field. Our work provides a versatile means to directly control confinement and organization, paving the way towards applications such as sorting particles based on motility or localizing active particles on demand.
活性胶体粒子通常对在边界处积累和被捕获表现出显著的亲和力。在此，我们设计了在电场作用下自推进的胶体与图案化障碍物之间的长程排斥相互作用。由于这些相互作用，粒子会远离障碍物并避免聚集。我们表明，通过调整施加电场的频率，我们可以精确且快速地控制障碍物的有效尺寸，从而调节粒子的接近距离。这一特性使我们能够实现对活性粒子的门控和可调限制，即它们可以根据施加的电场进入障碍物之间的区域。我们的工作提供了一种直接控制限制和组织的通用方法，为基于运动性对粒子进行分类或按需定位活性粒子等应用铺平了道路。
