Self-healing of nanofiber-based composites in the course of stretching
journal contributionposted on 17.01.2017 by Min Wook Lee, Soumyadip Sett, Sam S. Yoon, Alexander L. Yarin
Any type of content formally published in an academic journal, usually following a peer-review process.
Here we aim to elucidate the self-healing mechanisms in composites with embedded solution-blown nanofibers containing separate reservoirs of epoxy resin and hardener in their cores. In tensile tests of such composite materials with the resin- and hardener-containing solution-blown nanofibers embedded in a polymer matrix, it is shown that the fibers can be ruptured by stretching, thereby releasing the epoxy resin and hardener. Given a resting (or holding) period of 1–2 h, such materials can experience a restoration or even enhancement of stiffness in subsequent stretching, thereby displaying self-healing properties. In two model macroscopic experiments with a single crack tip, conducted in the Appendix with the aim to elucidate the self-healing mechanism, the epoxy resin and hardener released into the tip are shown to react with each other, resulting in a cured and hardened epoxy that heals the crack tip.