(3dg) Functional Surfaces and Interfaces for Composite and Biomedical Applications

Materials that can repair cracks and recover from mechanical failure are desirable. Because remendable materials both repair and prevent the propagation of cracks on the micro scale, they offer the potential for increased durability, safety, and cost efficiency for many applications. The focus of my PhD work was to understand the kinetic and thermodynamic parameters that control thermoreversible Diels-Alder bond formation in different types of healing polymeric systems. Such studies are necessary to optimize the healing ability of Diels-Alder-based systems and also contribute to the understanding of networks containing equilibrium controlled bonds. I have developed three healing systems for epoxy-amine thermosets based on the thermoreversible Diels-Alder reaction of furan and maleimide. In one, crack healing of a traditional epoxy-amine thermoset is induced by thermally reversible cross-linking of a secondary phase. In another, a furan-functionalized epoxy-amine thermoset can be healed with a bismaleimide solution at room temperature and minimal pressure and significant load recovery is possible multiple times in a given location. The third system allows for interfacial healing of glass fiber-reinforced epoxy-amine composites via compatible functionalization of glass fibers and the polymer network.

Interactions at the interface between the body and an implanted device determine the failure or success of the device. Optimizing surface conditions of titanium implants is necessary to increase the lifetime of implants and quality of life for millions of patients. Changes in topology have been shown to effect cell adhesion, shape, and motility. It is important that an implant surface is optimized for desired cell (such as osteoblast) adhesion and growth, while adhesion of undesired cells and proteins is minimized. One way to improve osteoblast adhesion and growth is to add appropriate growth factors to the enviroment. My posdoctoral research focuses on the development of improved biointerfaces with tailorable properties that are scalable and the ability to release growth factor.