Anisotropic nanoparticles offer considerable promise for applications but also present significant challenges in terms of their characterization. Recent developments in the electroless deposition of silver patches directly onto colloidal silica particles have opened up a simple and scalable synthesis method for patchy particles with tunable optical properties. Due to the reliance on patch nucleation and growth, however, the resulting coatings are distributed in coverage and thickness and some core particles remain uncoated. To support process optimization, new methods are required to rapidly determine patch yield, thickness and coverage. Here we present a novel approach based on multiwavelength analytical ultracentrifugation (MWL-AUC) which permits simultaneous hydrodynamic and spectroscopic characterization. The patchy particle colloids are produced in a continuous flow mixing process that makes use of a KM-type micromixer. By varying the process flow rate or metal precursor concentration we show how the silver to silica mass ratio distribution derived from the AUC-measured sedimentation coefficient distribution can be influenced. Moreover, through reasoned assumptions we arrive at an estimation of the patch yield that is close to that determined by arduous analysis of scanning electron microscopy (SEM) images. Finally, combining MWL-AUC, electrodynamic simulations and SEM image analysis we establish a procedure to estimate the patch thickness and coverage.

各向异性纳米粒子为应用提供了可观的前景，但在其表征方面也提出了重大挑战。将银片直接无电沉积到胶体二氧化硅颗粒上的最新进展为具有可调光学特性的片状颗粒开辟了一种简单且可扩展的合成方法。然而，由于依赖于贴片成核和生长，所得涂层的覆盖率和厚度分布均匀，并且一些核心颗粒保持未涂层。为了支持工艺优化，需要新方法来快速确定贴片产量、厚度和覆盖率。在这里，我们提出了一种基于多波长分析超速离心 (MWL-AUC) 的新方法，该方法允许同时进行流体动力学和光谱表征。片状颗粒胶体是在使用 KM 型微混合器的连续流动混合过程中产生的。通过改变工艺流速或金属前体浓度，我们展示了如何影响源自 AUC 测量的沉降系数分布的银与二氧化硅质量比分布。此外，通过合理的假设，我们得出的贴片产量估计值接近于通过扫描电子显微镜 (SEM) 图像的艰苦分析所确定的估计值。最后，结合 MWL-AUC、电动模拟和 SEM 图像分析，我们建立了一个程序来估计补丁厚度和覆盖率。通过改变工艺流速或金属前体浓度，我们展示了如何影响源自 AUC 测量的沉降系数分布的银与二氧化硅质量比分布。此外，通过合理的假设，我们得出的贴片产量估计值接近于通过扫描电子显微镜 (SEM) 图像的艰苦分析所确定的估计值。最后，结合 MWL-AUC、电动模拟和 SEM 图像分析，我们建立了一个程序来估计补丁厚度和覆盖率。通过改变工艺流速或金属前体浓度，我们展示了如何影响源自 AUC 测量的沉降系数分布的银与二氧化硅质量比分布。此外，通过合理的假设，我们得出的贴片产量估计值接近于通过扫描电子显微镜 (SEM) 图像的艰苦分析所确定的估计值。最后，结合 MWL-AUC、电动模拟和 SEM 图像分析，我们建立了一个程序来估计补丁厚度和覆盖率。