Materials science is a very important area of current research. This interdisciplinary field involves aspects of chemistry, physics, and engineering. Our interest lies mainly in establishing the molecular basis for bulk properties of materials and how materials respond to a variety of stresses. In many cases, this involves the investigation of surface and interface properties, which is where material failure often begins.
Response of Materials to Mechanical Stress
We are very interested in how materials respond to mechanical stress at the molecular level. We use various forms of spectroscopy, including Raman spectroscopy and nonlinear spectroscopy, specifically sum-frequency generation (SFG) and second harmonic generation (SHG), to probe the surfaces of materials before and after they are subjected to mechanical deformation. The spectroscopic investigations are supported by electron microscopy measurements. With these techniques, we are able to identify signatures of mechanical stress due to molecular-level changes at the surface of the material. These approaches have great potential for use in nondestructive testing applications.
Molecular Basis for Adhesion
Because SFG can probe buried interfaces as well as free surfaces, we can investigate the molecular structure of bonded materials. In a bonded system, two surfaces are held in mechanical contact by a layer of adhesive. Unfortunately, a full molecular basis for adhesive interactions has not been developed, primarily because of a lack of molecular level information on such systems. We want to systematically investigate bonded systems, such as polymers on solid substrates and industrial adhesive materials, to understand how changes in the molecular structure affect the strength of the adhesive interactions. We also want to understand the formation of adhesive bonds.
Scientific questions we want to address are:
What are the chemical and structural changes that take place as an adhesive cures?
How do changes in the environment affect this bond formation?
We also want to investigate aging phenomena.
How does the structure of the adhesive interface change over time, leading to bond failure?
The Interface of Science
Our research focuses on interfacial systems, but we are also interested in exploring interfaces of science. Other fields we could explore include mechanisms of chromatographic separation, biocompatible materials, interfacial properties of nanomaterials, heterogeneous atmospheric chemistry, lubrication, switchable surfaces, and others. Such projects will most likely involve collaboration with other members of the department and groups in other departments both on campus and at other universities. With the spectroscopic tools available to us, we are excited at the prospects of exploring a wide variety of interfacial systems. Opportunities are available for both graduate and undergraduate students.