论文标题
瞬态变质和光学加热的Janus胶体在二元液体混合物中的运动性
Transient coarsening and the motility of optically heated Janus colloids in a binary liquid mixture
论文作者
论文摘要
悬浮在近临界二进制液体混合物中的金封面的janus粒子可以在照明下自动播种。我们已经将这种粒子固定在狭窄的通道中，并使用实验和数值模拟研究了周围二元溶剂的非平衡动力学。对于后者，我们认为纯粹的扩散和流体动力模型。所有方法均表明早期动力学纯粹是扩散的，其特征是从胶体表面恒定速度向整体行驶的组成层。随后，设定的流体动力效应和瞬态状态被强质量浓度波动破坏，这是由于温度梯度和二进制液体混合物的临界点附近而产生的。它们产生了一种复杂的永久变化模式。对于移动粒子，瞬态动力学会导致与达到稳态后观察到的方向相反的方向。
A gold-capped Janus particle suspended in a near-critical binary liquid mixture can self-propel under illumination. We have immobilized such a particle in a narrow channel and studied the nonequilibrium dynamics of a binary solvent around it, using experiment and numerical simulations. For the latter we consider both a purely diffusive and a hydrodynamic model. All approaches indicate that the early time dynamics is purely diffusive and characterized by composition layers traveling with a constant speed from the surface of the colloid into the bulk. Subsequently, hydrodynamic effects set in and the transient state is destroyed by strong nonequilibrium concentration fluctuations, which arise as a result of the temperature gradient and the vicinity of the critical point of the binary liquid mixture. They give rise to a complex, permanently changing coarsening patterns. For a mobile particle, the transient dynamics results in propulsion in the direction opposite to that observed after the steady state is attained.
