Direct microencapsulation of pure polyamine by integrating microfluidic emulsion and interfacial polymerization for practical self-healing materials

Encapsulation of polyamines for the practical application of self-healing epoxy is promising yet challenging due to their high reactivity and good solubility in water and most organic solvents. Herein, we developed an innovative method to directly synthesize microcapsules containing pure polyamine by integrating microfluidic emulsion and interfacial polymerization. Using this integration to make full use of the advantages and avoid the shortcomings of the involved two techniques, the properties of the fabricated microcapsules could be delicately tailored according to the practical demands of self-healing materials. The superiority of the obtained polyamine microcapsules was demonstrated via a dual-microcapsule high-performance self-healing system with fully autonomous recoverability, high thermal and long-term stability, relatively fast healing kinetics. The highest healing efficiency of 111 ± 12% in terms of recovered mode I fracture toughness was achieved at room temperature for 48 h without any external intervention. The high performance, environmental stability, and low cost and toxicity introduced by the robust microcapsules promote the potential practical application of this self-healing system.