"What makes Materials Flexible or Rigid?"

Mike Thorpe
Departments of Physics, Chemistry and Biochemistry and Center for Biological Physics
Arizona State University

Abstract:

Have you ever wondered why some materials more flexible than others? Many interesting phenomena occur in material structures that are poised between rigid and flexible. In this talk, we describe the modern theory of rigidity and show how it can be used to analyze networks of constraints. These results can be used as input to geometrical simulation, where the various rigid parts of a system are moved, while maintaining all the constraints; both equalities and inequalities. These concepts can be introduced in high school by using popsicle sticks and cotter pins to construct frameworks in an interesting new approach involving hands-on self discovery. On a research level, this approach has led to important insights in both in zeolites that are important for cracking petroleum, manganites that exhibit colossal magnetoresistance, and proteins and protein complexes (like viruses) where flexibility is often associated with function.

Video of the Presentation

Brief Biography:

Michael Thorpe is Foundation Professor at Arizona State University, with appointments in Physics, Chemistry and Biochemistry. He previously had faculty appointments at Yale University and Michigan State University where he was University Distinguished Professor. His research interests are in the theory of disordered systems, with a special emphasis on properties that are determined by geometry and topology. He has a research background in condensed matter theory, and in recent years has used the mathematical theory of flexibility and mobility in glassy networks, and also in crystalline materials with disorder. His most recent work has been in biological physics. Proteins are stable enough to maintain a three-dimensional structure, but flexible enough for biological function. The aim of this research work is to find underlying principles and unifying concepts, to better understand the evolution and function of proteins and protein complexes. He was the Founding Director of the Center for Biological Physics at Arizona State University. In 2009-2010, he will be the Visiting Leverhulme Professor at Imperial College in London.