Microvascular Networks for Continuous Self -Healing Materials

122 p.Thesis (Ph.D.)--University of Illinois at Urbana-Champaign, 2007.Microcapsule-based and hollow glass fiber-based self-healing composites enable a single repair of crack damage in a given location. Re-mendable polymers have demonstrated crack mending for multiple cycles, but only with heat treatment and applied pressure. We demonstrate, for the first time, the autonomic characteristics of microencapsulated systems with the ability to heal repeated damage events in a continuous self-healing coating on a microvascular substrate. A three-dimensional, interconnected microvascular network in the substrate serves as a delivery system for healing materials to heal damage in a polymer coating. Two approaches to microvascular delivery are explored: one using a fluid monomer in the network with solidphase catalyst particles in the coating, and one using two or more separate networks with two fluid healing components. In both systems, the fluid(s) flow from the microchannels into the crack plane through capillary action, and polymerization occurs to heal the crack. In the single-fluid system, a single crack in a brittle epoxy coating is healed as many as seven times, and the ability to heal continuously is limited only by the availability of catalyst. The two-part healing system contained in separate networks in a specimen has significant potential to extend the repeatability of the healing process due to the microvascular supply of both healing components. Preliminary tests of this two-part system demonstrate that multiple healing cycles are possible.U of I OnlyRestricted to the U of I community idenfinitely during batch ingest of legacy ETD