Chemical Engineering Department

Presents

Professor Anna Balazs

Department of Chemical Engineering

University of Pittsburgh

Computational modeling of self-healing materials

We describe recent computational studies to design a variety of self-healing materials. In particular, we demonstrate the self-healing behavior of materials composed of nanoscopic gel particles that are interconnected into a macroscopic network by both stable and labile bonds. Under mechanical stress, the labile bonds between the nanogels can break and readily reform with reactive groups on neighboring units. This breaking and reforming allows the units in the network to undergo a structural rearrangement that preserves the mechanical integrity of the sample. The simulations show that just a small fraction of labile bonds leads to a significant increase in the stress needed to induce fracture. Thus, the labile bonds can significantly improve the tensile strength of the material. We then describe design rules for creating  “artificial leukocytes” that facilitate the healing of the damaged substrates. In particular, we examine the behavior of nanoparticle-filled microcapsules and determine the optimal conditions for driving these micro-carriers to fill cracks in fractured surfaces. Finally, we design oscillating polymer gels that effectively act as a “skin” by signaling mechanical impact. Computational research into self-healing materials is still in its infancy but, ultimately, progress in this field can greatly facilitate the fabrication of the next generation of adaptive materials that both monitor their structural integrity and mend themselves before any catastrophic failure can occur.

Thursday, September 3, 11:00 am in ChE 005

Refreshments will be served at 10:45 am in ChE Lobby