Department of Physics, University of California San Diego, 9500 Gilman Drive, La Jolla, CA, 92093-0319, USA.
Ladhyx, Ecole Polytechnique, Institut Polytechnique de Paris, 91128, Palaiseau Cedex, France.
Nat Commun. 2019 Jul 29;10(1):3380. doi: 10.1038/s41467-019-11362-y.
Molecular motors are essential to the living, generating fluctuations that boost transport and assist assembly. Active colloids, that consume energy to move, hold similar potential for man-made materials controlled by forces generated from within. Yet, their use as a powerhouse in materials science lacks. Here we show a massive acceleration of the annealing of a monolayer of passive beads by moderate addition of self-propelled microparticles. We rationalize our observations with a model of collisions that drive active fluctuations and activate the annealing. The experiment is quantitatively compared with Brownian dynamic simulations that further unveil a dynamical transition in the mechanism of annealing. Active dopants travel uniformly in the system or co-localize at the grain boundaries as a result of the persistence of their motion. Our findings uncover the potential of internal activity to control materials and lay the groundwork for the rise of materials science beyond equilibrium.
分子马达对生命至关重要，它们产生的涨落有助于物质运输和组装。主动胶体通过消耗能量来运动，它们也具有类似的潜力，可以用于由内部力控制的人造材料。然而，它们作为材料科学中的动力源的应用还很少。在这里，我们通过适度添加自推进的微颗粒，展示了单层被动珠的退火过程的大规模加速。我们用一个驱动活性涨落并激活退火的碰撞模型来解释我们的观察结果。实验与布朗动力学模拟进行了定量比较，进一步揭示了退火机制中的动力学转变。由于其运动的持续性，活性掺杂剂在系统中均匀地移动或在晶界处共定位。我们的发现揭示了内部活动控制材料的潜力，并为超越平衡的材料科学的兴起奠定了基础。
