Abstract:

Unique mechanical and thermal properties can be achieved in new classes of low density organic-inorganic hybrids where individual polymer molecules are confined at length scales of only a few nanometers in the pores of an inorganic matrix. In particular, significant toughening is induced through a novel “molecular bridging” mechanism in which individual confined polymer chains are stretched and pulled out of the matrix pores behind an advancing crack tip. Such toughening mechanism is not found in other composite materials. In this presentation we discuss two strategies to further improve the reliability of such hybrids: (1) Controlling the interactions of the confined polymer molecules with the pore surface of the matrix to increase the fracture toughness and glass transition temperature, and suppress physical aging of the confined polymers. (2) Incorporating heat-resistant polyimides into the hybrids to improve the thermal-oxidative stability for high temperature service.

Speaker’s Bio:

Can Wang is a Ph.D. candidate in Chemistry and Ph.D. minor candidate in Materials Science and Engineering at Stanford University, working under the guidance of Prof. Reinhold Dauskardt. His Ph.D. research has been focused on the reliability of low density organic-inorganic hybrid thin films. He has co-authored 4 research papers.