Self-Propulsion and Active Motion of Janus Ellipsoids.
Self-Propulsion and Active Motion of Janus Ellipsoids.
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Janus 椭球体的自推进和主动运动。
DOI：
10.1021/acs.jpcb.8b08303
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发表时间：
2018
期刊：
影响因子：
--
通讯作者：
M. Solomon
中科院分区：
文献类型：
--
作者：
Onajite Shemi;M. Solomon
过氧化氢催化分解产生的铂包覆聚苯乙烯长聚苯乙烯椭球体的推进，其特征在于活性粒子的轨迹直接可视化。这些Janus椭球是通过将微米级聚苯乙烯球拉伸成不同的长宽比制成的；然后沿着椭球的长轴将一半的粒子纵向覆盖，并沉积铂。这些粒子在浓度为2-8% （w/v）的过氧化氢水溶液中表现出复杂的动力学轨迹。在这个范围内，随着过氧化氢浓度的增加，观察到从三维被动布朗运动到二维主动运动的转变。从被动运动到主动运动的转变由4% （w/v）的过氧化氢完成。我们量化了在最高过氧化氢浓度下，颗粒长径比对均方位移和均方角位移的影响。将单个粒子的二维轨迹分为三类进行动力学分析。在第一类中，在旋转扩散的特征时间尺度上，弹道椭球的平移量至少是纯扩散椭球的5倍。在第二类中，自旋椭球体只移动很短的距离，主要围绕小轴旋转；这种旋转持续了许多圈。第三类捕获的轨迹包括重要的平移和旋转。我们考虑观察到的运动类别的物理起源，并提取由催化产生的推进所产生的力和扭矩作为展弦比的函数。粒子速度，也就是主动力，随着长径比的增加而增加。
The propulsion of platinum-coated polystyrene prolate ellipsoids, as generated by catalytic decomposition of hydrogen peroxide, is characterized by direct visualization of the trajectories of the active particles. These Janus ellipsoids were fabricated by stretching micron-sized polystyrene spheres into different aspect ratios; half of the particle is then capped lengthwise along the ellipsoid's major axis, with platinum deposition. These particles exhibit complex dynamical trajectories in aqueous solutions of hydrogen peroxide of concentration in the range of 2-8% (w/v). In this range, a transition from three-dimensional passive Brownian motion to two-dimensional active motion is observed as the hydrogen peroxide concentration is increased. This transition from passive to active motion is complete by 4% (w/v) hydrogen peroxide. We quantify the effect of particle aspect ratio on the mean-squared displacement and mean-squared angular displacement at the highest hydrogen peroxide concentration. The two-dimensional trajectories of the individual particles were grouped into three categories for dynamical analysis. In the first category, ballistic ellipsoids translate at least 5 times more than purely diffusive ellipsoids at the characteristic time scale of rotational diffusion. In the second category, spinning ellipsoids move only short distances with a dominant rotation about the minor axis; this rotation persists for many revolutions. A third category captures trajectories that include both significant translation and rotation. We consider the physical origins of the observed categories of motion and extract the forces and torques generated by the catalytically generated propulsion as a function of aspect ratio. The particle velocity, and therefore the active force, increases with the aspect ratio.
影响因子：
13.3
作者：
Wu, Liz Y.;Ross, Benjamin M.;Lee, Luke P.
通讯作者：
Lee, Luke P.
影响因子：
1.8
作者：
Ebbens, S.;Gregory, D. A.;Golestanian, R.
通讯作者：
Golestanian, R.
影响因子：
3.4
作者：
Bayly, P. V.;Lewis, B. L.;Dutcher, S. K.
通讯作者：
Dutcher, S. K.