喷雾干燥颗粒表面形貌形成过程粗粒化模拟

Coarse-grained simulation of surface morphology formation for spray dried particles

喷雾干燥制粒有着广泛的应用。颗粒表面形貌的调控对提升颗粒品质起到至关重要的作用。本研究旨在建立分子尺度粗粒化模型,描述蒸发诱导下溶质的自组装行为,预测不同干燥条件下表面形貌的演变过程。文中建立的粗粒化网格Monte Carlo模型可以处理球形固体溶质,并充分考虑各物质之间相互作用及相变过程。开发的分析方法可以定量蒸发过程中液体残留率、颗粒分布与组装形貌。通过初步的二维系统模拟可以发现,溶剂不断蒸发过程中溶质逐渐移动,形成各种自组装结构。溶剂化学势越小,液体残留率越低。随着初始溶质浓度升高,最终溶质组装形貌从点状变为网状结构。不同的物质间相互作用也会导致紧密或松散的溶质分布。

Spray drying for powder production has a wide range of applications. On-aim control of surface morphology of spray dried particles is critical for achieving improved powder quality. This work aims at a molecular scale coarse-grained model that can characterize evaporation induced self-assembly of solute during the drying process. Thus, surface morphology evolution under different drying conditions can be predicted. The lattice Monte Carlo model developed in this work can take care of spherical shaped solute molecules and comprehensive interactions between species in the system. The analysis method is capable of quantifying solvent residue and solute distribution as well as its assembly structure. The simulations carried out in 2D show that different assembly structures can be formed under investigated conditions. The decrease of solvent chemical potential energy leads to the decreased solvent residual ratio. With the increase of initial solute concentration, the final assembly pattern changes from disk-shape to net-shape. Furthermore, assembly patterns can be tailored through manipulating interactions between species in the system.