利用COMSOL Multiphysics软件–聚合物微球材料的数值模拟

Numerical Simulation of Polymer Microsphere Material Using COMSOL Multiphysics Software

摘要: 目的：本研究旨在探究模拟微流控制备聚合物微球的影响因素，优化微流控的结构尺寸，为实验操作提供理论基础并降低实验成本和时间。方法：用COMSOL Multiphysics 6.2模拟软件建立2D微流控结构，采用两相水平集法探究流动聚焦结构和同轴微流通道结构对聚合物微球生成的影响，通过建立流动聚焦形微通道中聚合物微球生成的数值模型，系统地研究了微液滴的生成以及不同控制参数对微球尺寸频率和稳定性的影响。结果：在聚焦形微通道中，液滴的生成主要是因为连续相对分散相的挤压和剪切作用，保持其他因素不变，当界面张力增加时，聚合物微球的尺寸增加并且频率降低；当分散相粘度增加时，聚合物微球的尺寸减小但是生成频率增加，并且液滴粘度增加得越快，聚合物微球的生成时间越长；当连续相粘度增大时，聚合物微球的尺寸增大，微球边界清晰且稳定性增加；当连续相流量增加时，聚合物微球的尺寸减小但生成频率增加将近2.1倍。液滴尺寸偏小时，可以通过适当增加界面张力和连续相流量来改变聚合物微球生成的尺寸和频率。结论：利用COMSOL软件研究微流控中不同微通道的聚合物微球生成和操控机理，揭示微流控液滴的流动机理和规律，满足了聚合物微球不同的生成要求，克服了现实实验的局限性，对用于吸附染料废水的聚合物微球的制备具有重要的实际意义。

Abstract: Objective: This study aims to explore the influencing factors of polymer microsphere preparation by microfluidic simulation, optimize the structural dimensions of microfluidic control, provide a theoretical basis for experimental operation and reduce experimental costs and time. Methods: A 2D microfluidic structure was established using COMSOL Multiphysics 6.2 simulation software. The two-phase level set method was adopted to investigate the effects of flow focusing structure and coaxial microfluidic channel structure on the generation of polymer microspheres. By establishing a numerical model of polymer microsphere generation in a flow focusing microchannel, the generation of microdroplets and the effects of different control parameters on the size, frequency and stability of microspheres were systematically studied. Results: In the focusing microchannel, the generation of droplets is mainly due to the squeezing and shearing of the continuous phase on the dispersed phase. Keeping other factors constant, when the interfacial tension increases, the size of the polymer microspheres increases and the frequency decreases; when the viscosity of the dispersed phase increases, the size of the polymer microspheres decreases but the generation frequency increases, and the faster the viscosity of the droplets increases, the longer the generation time of the polymer microspheres; when the viscosity of the continuous phase increases, the size of the polymer microspheres increases, the boundaries of the microspheres are clear and the stability increases; when the flow rate of the continuous phase increases, the size of the polymer microspheres decreases but the generation frequency increases by nearly 2.1 times. When the droplet size is small, the size and frequency of polymer microsphere generation can be changed by appropriately increasing the interfacial tension and the flow rate of the continuous phase. Conclusion: The use of COMSOL software to study the generation and manipulation mechanisms of polymer microspheres in different microchannels of microfluidic control, revealing the flow mechanism and laws of microfluidic droplets, meets the different generation requirements of polymer microspheres and overcomes the limitations of real experiments. It has important practical significance for the preparation of polymer microspheres used for adsorbing dye wastewater.