论文标题
长时间尺度上的微粒子和纳米粒子的粒度依赖性声学运动和耗竭
Particle-size-dependent acoustophoretic motion and depletion of micro- and nanoparticles at long time scales
论文作者
论文摘要
我们提出了三维测量的微粒尺寸依赖性的声学运动，直径从4.8 um降至0.5 UM，悬浮在均匀或不均匀的液体中，玻璃硅微通道内的均匀或不均匀的流体，暴露于站立超声波。为了研究随着粒径的减小，从辐射力占主导地位的运动主导的跨界，我们将先前的研究扩展到长时间，在长时间尺度上，小于跨侧尺寸的颗粒与通道宽度相当的距离移动。我们观察到小于交叉大小的颗粒的粒度依赖性粒子耗竭。通过考虑布朗运动的数值模拟，这种耗竭的耗竭背后的机制合理化了。在实验上，不均匀液中的粒子轨迹在早期的大部分微通道上都集中在大部分微通道上，即使是针对低于临界大小的颗粒，这清楚地表明了操纵亚微米颗粒的潜力。
We present three-dimensional measurements of size-dependent acoustophoretic motion of microparticles with diameters from 4.8 um down to 0.5 um suspended in either homogeneous or inhomogeneous fluids inside a glass-silicon microchannel and exposed to a standing ultrasound wave. To study the cross-over from radiation force dominated to streaming dominated motion as the particle size is decreased, we extend previous studies to long time scales, where the particles smaller than the cross-over size move over distances comparable to the channel width. We observe a particle-size-dependent particle depletion at late times for the particles smaller than the cross-over size. The mechanisms behind this depletion in homogeneous fluids are rationalized by numerical simulations which take the Brownian motion into account. Experimentally, the particle trajectories in inhomogeneous fluids show focusing in the bulk of the microchannel at early times, even for the particles below the critical size, which clearly demonstrates the potential to manipulate submicrometer particles.
