Arora Pragya, Sood A K, Ganapathy Rajesh
Chemistry and Physics of Materials Unit, Jawaharlal Nehru Centre for Advanced Scientific Research, Jakkur, Bangalore 560064, India.
Department of Physics, Indian Institute of Science, Bangalore 560012, India.
Sci Adv. 2021 Feb 26;7(9). doi: 10.1126/sciadv.abd0331. Print 2021 Feb.
In many active matter systems, particle trajectories have a well-defined handedness or chirality. Whether such chiral activity can introduce stereoselective interactions between particles is not known. Here, we developed a strategy to tune the nature of chiral activity of three-dimensionally printed granular ellipsoids without altering their shape or size. In vertically agitated monolayers of these particles, we observed two types of dimers form depending on the chirality of the pairing monomers. Heterochiral dimers moved collectively as a single achiral active unit, while homochiral ones formed a translationally immobile spinner. In active racemic mixtures, the former was more abundant than the latter, indicating that interactions were stereoselective. Through dimer lifetime measurements, we further provide evidence for chiral self-recognition in mixtures of particles with different chiral activities. We lastly show that, at fixed particle number density, changing the net chirality of a dense active liquid fundamentally alters the nature of collective relaxation.
在许多活性物质系统中，粒子轨迹具有明确的手性或螺旋性。尚不清楚这种手性活性是否会在粒子之间引入立体选择性相互作用。在此，我们开发了一种策略，可在不改变其形状或大小的情况下调节三维打印颗粒状椭球体的手性活性性质。在这些粒子的垂直振动单层中，我们观察到根据配对单体的手性形成了两种类型的二聚体。异手性二聚体作为单个非手性活性单元集体移动，而同手性二聚体则形成平移不动的旋转体。在活性外消旋混合物中，前者比后者更丰富，这表明相互作用是立体选择性的。通过二聚体寿命测量，我们进一步为具有不同手性活性的粒子混合物中的手性自识别提供了证据。我们最后表明，在固定的粒子数密度下，改变致密活性液体的净手性会从根本上改变集体弛豫的性质。
