Process regulation for encapsulating pure polyamine via integrating microfluidic T-junction and interfacial polymerization

The quality of microcapsules directly determines the performance of microcapsule-based functional materials, such as self-healing materials. How to achieve high-quality microcapsules depends on not only the selected microencapsulation technique but also the process regulation. Herein, using tetraethylenepentamine (TEPA) as the core target to be encapsulated by a novel microencapsulation technique through integrating microfluidic T-junction and interfacial polymerization, this investigation studied how the process parameters influence the microencapsulation process and the quality of the synthesized microcapsules regarding the size, morphology, shell structure, and composition. The studied parameters include the solvent type and surfactant concentration in the co-flow solution, the fed volume of the co-flow solution, the types of the solvent, catalyst, and shell-forming monomer in the reaction solution for the shell-growth stage, and the reaction temperature at the shell-growth stage. The influence mechanisms were established based on the observations, and the optimized parameter combination for the process was achieved. Through the parametric study for the microencapsulation technique, this study also lays a solid foundation for the technique to fabricate microcapsules containing other functional substances with high quality.