A Molecular Dynamics Simulation On Self-Healing Behavior Based On Disulfide Bond Exchange Reactions

The self-healing polymers based on dynamic covalent bonds or non-covalent interactions have been widely reported in experiments. However, the self-healing theory and mechanism still need to be explored further. In this paper, molecular dynamics simulations are performed to investigate the self-healing mechanism based on disulfide bond exchange reactions at the atomic scale. The microstructures of sample during self-healing process are tracked, and the mechanical properties varying with healing time are examined by uniaxial tension tests. In addition, the effect of crosslink density on the self-healing efficiency and mechanical properties is investigated. The results reveal that the high crosslink density has a positive effect on the mechanical properties and a negative effect on the mobility of molecular chains. The effect of healing time on healing efficiency is also studied, which exhibits the same tendency as the experimental results. Finally, the stress relaxation test is simulated to study the dynamic feature of exchangeable disulfide bonds. The results indicate that the system with shorter stress relaxation time has higher healing efficiency.