A fundamental understanding of the drying behavior of droplets containing solids or solutes is important for various industrial applications. However, droplets are typically highly polydisperse and time-resolved imaging data of the process dynamics are often lacking, which makes it difficult to interpret the effects of different drying parameters. Here, the controlled drying of monodisperse emulsion droplets containing colloidal silica nanoparticles and their subsequent assembly into mesoporous silica microspheres (MSMs) is investigated using an optical microscope outfitted with a heating and vacuum stage. Quantitative imaging results on droplet shrinkage and observed contrast are compared with a theoretical mass-transfer model that is based on the droplet number density, solvent characteristics and temperature. The results presented here provide key insights in the time-resolved formation of MSMs and will enable an optimized direct synthesis of monodisperse MSMs for separation applications and beyond.

对包含固体或溶质的液滴的干燥行为的基本了解对于各种工业应用很重要。然而，液滴通常是高度多分散的，并且通常缺乏过程动力学的时间分辨成像数据，这使得难以解释不同干燥参数的影响。在这里，使用配备有加热和真空台的光学显微镜研究了含有胶态二氧化硅纳米颗粒的单分散乳液液滴的受控干燥及其随后组装为介孔二氧化硅微球（MSM）的过程。将基于液滴收缩和观察到的对比度的定量成像结果与基于液滴数密度，溶剂特性和温度的理论传质模型进行比较。