Rabolt has pioneered the application of focal plane arrays to infrared spectroscopy, bringing about portable instruments that are capable of recording an infrared spectrum in less than 100 microseconds, with a microsecond being one millionth of one second. This has allowed the study of dynamics in organic and polymeric materials and provided, for the first time, insights into how molecules orient and order as they assemble on surfaces.

Rabolt also holds a position as an associated faculty member at the Delaware Biotechnology Institute, where he maintains a laboratory with several graduate students working on tissue engineering scaffolds.

Before joining UD in 1996 as chairperson of the College of Engineering's Materials Science Program, which became the Department of Materials Science and Engineering under his stewardship, Rabolt was a research staff member in the IBM Research Division in San Jose, Calif. There, he was a founding co-director of the Center on Polymer Interfaces and Macromolecular Assemblies, a National Science Foundation-sponsored partnership among Stanford University, IBM, the University of California Davis and the University of California Berkeley.

Rabolt's research interests are in the area of polymer deformation and orientation, electrospun polymer nanofibers, organic thin films on surfaces, infrared and Raman spectroscopy, and biomolecular materials.

He received the 2000 A.E. Michelson Award in Molecular Spectroscopy sponsored by the Bomem analytical products company, the 1993 Ellis Lippincott Award in Vibrational Spectroscopy, the 1992 Louis A. Strait Award in Applied Spectroscopy, the 1990 Williams-Wright Award in Molecular Spectroscopy and the 1985 Coblentz Award.

In addition to serving as chairperson of three Gordon Research Conferences--on organic thin films in 1996 and on polymers and on vibrational spectroscopy in 1990--Rabolt is an American Physical Society Fellow and was an associate editor of the American Chemical Society journal Macromolecules from 1992-2001.

He served as a member of the Gordon Research Conference's Scheduling and Selection Committee from 1997-2003 and is currently a member of NASA's Microgravity Materials Science Advisory Committee.

Rabolt has co-authored more than 180 peer-reviewed publications, one book and eight patents.

Previous recipients of the Pittsburgh Spectroscopy Award have included Gerhard Herzberg (1962), Paul Lauterbur (1987) and Ahmed Zewail (1997), who later went on to become Nobel Laureates.

"THE DESIGN gets rid of moving parts--making it rugged and useful outside of the laboratory," Rabolt said. He added that planar-array spectrometers could be useful, for example, in online chemical processing, homeland security, and other applications. Thus far, however, the Delaware group has focused on in-lab measurements to test the new design.

In one test, Rabolt and coworkers examined the growth of monolayer films of trichlorosilanes on glass. By monitoring frequency and intensity changes in CH2 stretching bands, the group was able to discern conformational changes indicative of molecular ordering as the layers assembled. The group also found that hexane is a better solvent for deposition than benzene or toluene (Langmuir, published online March 11, http://dx.doi.org/10.1021/la0208878).

Rabolt pointed out that the detector, which is a 256 x 320 array of InSb dots, registers signals in roughly 50 microseconds, but the readout step takes some 17 milliseconds. The holdup is due to the relatively slow readout electronics, but commercially available electronics are constantly improving, he said. Now the group is working on design modifications that include other gratings and detectors in order to broaden the technique's spectral range. The researchers are also developing methods to probe film deposition in real time.(By MITCH JACOBY, C&EN CHICAGO)

A team of researchers has developed a rugged portable detection system that could provide real-time recognition of chemical and biological weapons using infrared spectroscopy.
John Rabolt, Mei-Wei Tsao, Douglas Elmore and Simon Frisk of the University of Delaware, and Bruce Chase of the DuPont Company developed the planar array infrared spectrograph with GOALI (Grant Opportunities for Academic Liaison with Industry) and instrumentation grants from the National Science Foundation (NSF).
The device, which is now about the size of a large shoebox, can detect even small amounts of chemical weapons agents in solid, liquid or vapor phases.
It is also possible that the device can sense chemical agents at a distance, although Rabolt said further research on that is now being conducted. "We are planning to test the detectivity of our new PA-IR using a telescopic collection system that should be able to detect the presence of certain chemical agents at large distances away from our detector."
Using the analyte that is specific to a given biological agent, the device can easily and quickly sense the agent's presence. "Adding a series of such sensors near the at-risk sites could report back real-time findings via wireless transmitters.", said Rabolt.
Although its ability to detect chemical and biological weapons is of great interest given the recent terrorist attacks, the device also has broad industrial applications. It can be used to make "real-time" measurements of the thickness and chemical composition of various films, coatings and liquids.
Rabolt said: " Our PA-IR system will enable companies that run production lines at extremely fast speeds to cut down on waste by keeping better track of imperfections or variations in product quality as it is being manufactured."
Advantages of the new UD system over other spectroscopy devices are: high sensitivity, fast data acquisition and the absence of moving parts. Rabolt indicated that "It is the latter that makes the PA-IR rugged, portable, and reliable. Its integrity is not compromised by aggressive environments."
Rabolt and Tsao are working to further miniaturize the system to the size of a lunchbox and to expand its capabilities. The goal is to provide a generalized version for laboratory use and a specialized version for customized material sensing applications such as industrial, military and environmental monitoring.
Rabolt said the invention resulted from the marriage of spectroscopy technologies from the 1960s with the high sensitivity detection technologies of the 21st Century. He said: " Early spectroscopy devices were based on the use of light sources (lamps), the light from which could be broken into the various colors of the spectrum. Each material or substance absorbs a characteristic set of those colors providing a fingerprint."

Because that process was lengthy and laborious, each color being broken down and applied one at a time, it was replaced by Fourier Transform spectroscopy, a multiplex technique based on inteferometry, which could record the entire color spectrum at once.
¡°The problem with such Fourier transform (FT) instruments," Tsao suggests" is its size and the required moving parts. FT-IR instruments use precision machined mechanisms to facilitate the moving mirrors." " In many cases." Tsao said," parts made by single-point diamond turning are required." "The likelihood that such intricate machinery can survive portable application scenarios is low and that is why FTIR have been confined to laboratory environment for the most part."
The UD design has a small footprint and most importantly, it has no moving part. It relies on an infrared light bulb and a focal plane array similar to a charge-coupled device, or CCD, which can be found in modern digital camera.
The UD device "uses highly sensitive multi-element infrared detectors and can detect things that can't be detected using Fourier transform spectroscopy which employs a single element detection," Rabolt said.
And it can do that very quickly because of its fast data acquisition capability. Where it could take Fourier instruments on the order of hours to analyze an oil spill on the water ---- lost time that could have dire environmental consequences, the UD device can perform the same analysis in 30 seconds and can provide more accurate data.
In addition, the device is very simple in both design and construction. Tsao said:" We learned from years of instrumentation experience that the simpler the design is, the less likely it will go wrong¡­.." He dds," one can easily envision a version of this device made with a single block of metal where all the metal junctions, such as welds and bolts, are removed."