Self-healing of wounds in biological systems involves multiple-step healing solutions. For example, the healing of human skin relies on fast forming blood platelet to seal the wound before the slow regeneration of the final repair tissues. This project aims to understand a novel two-step healing process via a shape memory polymer (SMP) based syntactic foam for impact mitigation. The two-step (seal then heal) scheme will work in such a way that the thermoset SMP matrix will first close or significantly narrow the crack opening by confined shape recovery (Step 1) and then the thermoplastic particles, which are uniformly dispersed in the SMP matrix, will melt, diffuse, and glue the two sides of the crack by physical entanglement of thermoplastic/SMP molecules (Step 2). The effect of various design parameters such as programming or training of the foam on impact response and self-healing efficiency will be investigated through theoretical modeling and experimental testing.
Syntactic foam, hollow microspheres dispersed in a polymer matrix, has been widely used in many lightweight engineering structures such as aircraft, ship, auto, train, tank, offshore oil platform, bridge deck, etc. This project will provide syntactic foams with self-healing capabilities so that these structures can repair their internal damage autonomously, repeatedly, efficiently, and at molecular-length scale. This project will also contribute to graduate and undergraduate education by directly involving them, including minority students, in this research. It will also be disseminated to high school students and general public through a project website and scholarly publications.
