The primary goal of our research group is to develop the fundamental science and application technology for the sensor system components that are common to the platforms which can meet significant sensing needs such as for medical diagnostics, national defense and energy security.  Current focus is on acoustic wave devices for these applications.  The sensing principle in these devices is the perturbation of elastic waves in solids by environmental variables, and its recognition by suitable electronics.  A variety of these acoustic waves at radio frequencies are excited in various piezoelectric materials in our laboratory using suitably designed micro-fabricated electrodes.  These transducers are functionalized with sensing layers that interact with analytes to form selective, sensitive, fast-responding and robust sensors.  Our recent successes include palladium and palladium-alloy functionalized single walled carbon nanotube (Pd-SWNT) interfaces to a Rayleigh surface acoustic wave transducer for superior hydrogen sensing, a polymer functionalized, high frequency thickness shear mode (TSM) transducer for organic vapor detection and process monitoring, and a hexagonal transducer that propagates guided shear horizontal surface acoustic waves in one direction while propagating waves with substantial shear vertical components in others to achieve differential sensing of multiple biomarkers, for applications to ovarian cancer and trauma biomarker sensing.

Sensor response modeling at multiple time and length scales is integral to our research, and includes perturbation theories, and simulation techniques from electronic structure calculations, molecular-level simulation and finite element methods for interpreting the response of these acoustic wave devices to environmental disturbances.  Such accurate models allow for designing of superior sensors, and for utilizing these transducers in materials characterization.  Truly accurate models allow for measurement of the physical properties of materials that perturb the acoustic waves in these devices.  Such measurements in our laboratory include sorption, diffusion, and viscoelastic properties of polymer/solvent systems, extremely low vapor pressures and enthalpies of vaporization of solids, and phase transitions in hydrogel thin films exposed to various environments.  

Techniques and methods utilized for sensing material synthesis, characterization, and theoretical understanding are utilized for other applications as well in our research group.  One current project is the functionalization of SWNTs with drugs, proteins and siRNA and their delivery to cells and other targeted areas of orthopedic interest, in collaboration with researchers at Shriners Hospital.  Another is the understanding of Fischer-Tropsch catalysis by nanomaterials (cobalt, in particular) through density functional theory and molecular dynamics calculations.  A third is the synthesis, characterization, and electronic structure simulation of complex metal hydride materials and metalorganic frameworks for hydrogen storage. 

Characteristics of each research project in our research group are its interdisciplinary nature and emphasis on both theory and experiment.  This allows for the most efficient utilization of resources in a growing research university, and provides the best possible training for research students in formulating innovative solutions to difficult scientific and technological problems.