纳米粒子系综对流扩散耦合的时间依赖性
Time dependence of advection-diffusion coupling for nanoparticle ensembles
摘要：
与纯扩散相比，对流-扩散耦合可以将颗粒和溶质分散增强几个数量级，其中对于诸如纳米孔或血管的受限流动区域达到稳定状态。在这里，通过使用倏逝波显微镜，我们测量的第一次完整的动态泰勒色散，突出了初始浓度分布的关键作用。我们在亚微米近表面流动中进行随时间变化的纳米分辨颗粒分散测量，包括纳米颗粒尺寸、速度梯度和粘度。这样的分辨率允许测量的完整的动态方法和交叉到稳定状态，揭示了一个家庭的主曲线。值得注意的是，我们的研究结果表明，动力学敏感地依赖于纳米粒子的初始空间分布。这些观察结果与现有的分析模型和数值模拟在定量上一致。我们预计，我们的研究将是在纳米尺度上观察和模拟更复杂情况的第一步，例如在纳米约束流中的目标寻找和化学反应，动态吸附和捕获问题，以及纳米级药物递送系统。
英文摘要：
Advection-diffusion coupling can enhance particle and solute dispersion by orders of magnitude as compared to pure diffusion, with a steady state being reached for confined flow regions such as a nanopore or blood vessel. Here, by using evanescent wave microscopy, we measure for the first time the full dynamics of Taylor dispersion, highlighting the crucial role of the initial concentration profile. We make time-dependent, nanometrically-resolved particle dispersion measurements varying nanoparticle size, velocity gradient, and viscosity in sub-micrometric near-surface flows. Such resolution permits a measure of the full dynamical approach and crossover into the steady state, revealing a family of master curves. Remarkably, our results show that the dynamics depend sensitively on the initial spatial distribution of the nanoparticles. These observations are in quantitative agreement with existing analytical models and numerical simulations performed herein. We anticipate that our study will be a first step toward observing and modelling more complex situations at the nanoscale, such as target finding and chemical reactions in nanoconfined flows, dynamical adsorption and capture problems, as well as nanoscale drug delivery systems.
机构、总结、中文摘要均由AI分析而来，可能存在错误，请以论文正文为准。
