Professor Benziger's interests are in chemical reaction engineering and catalysis. His recent work has focused on reactors for organic vapor deposition for electronic devices, design, operation and control of Polymer Membrane Fuel Cells, and new reactor processing for sulfur removal from petroleu...
Professor Benziger's interests are in chemical reaction engineering and catalysis. His recent work has focused on reactors for organic vapor deposition for electronic devices, design, operation and control of Polymer Membrane Fuel Cells, and new reactor processing for sulfur removal from petroleum. In collaboration with Professor Steve Forrest Professor Benziger and has developed new reactor designs for the successful implementation of continuous large scale process of organic thin films for OLEDs and patterning methods with Organic Vapor Phase Jet Deposition. This work has successfully demonstrated the key design and control parameters for OVPD and OVJP key to the demonstrations of these techniques by Professors Forrest's and Benziger's groups. In the Fuel Cell area Professor Benziger's group has developed new reactor configurations for Polymer Electrolyte Membrane Fuel Cells that provide the essential information for controlling the dynamic behavior of PEM fuel cells. This work has demonstrated the existence of steady state multiplicity in PEM fuel cells along with a key discovery of the coupling of the chemical reaction in the fuel cell with mechanical relaxation processes in the polymer membrane. Professor Benziger and his group has also demonstrated a new sulfur recovery process for hydrocarbons streams that operates at low temperature and with has very low energy requirements. Professor Benziger has been a part of the Borexino Solar Neutrino collaboration where he has led the group that developed the methodology and equipment to purify multi-ton quantities of liquid scintillator. Reaction Engineering of Organic Vapor Phase Deposition. In collaboration with Professor Steve Forrest (Electrical Engineering) we have developed novel reactor designs and operation for deposition of low molecular weight organics for LED and TFT applications. This has led to successful design and operation of a transport reactor for continuous depostion on large area substrates. In the past year we have demonstrated a new process of organic vapor jet printing (OVJP), where we have been able to directly pattern organic semiconductors onto substrates with micron resolution from a vapor jet at atmospheric pressure. Dynamics of Polymer Electrolyte Membrane Fuel Cells. We initiated a program to study the dynamics of polymer electrolyte membrane (PEM) fuel cell operation under varying load, temperature and start-up. . A key discovery in our lab has been the demonstration of multiple steady states in the PEM fuel cells. This work was very exciting as it demonstrated a new concept in autocatalyticity, where a reaction product had positive feedback with the transport of protons in a membrane. We demonstrated ignition/extinction phenomena and then discovered the condition where 5 steady states existed. The five steady states led to the discovery of the importance of the swelling properties of polymer membranes on humidity control. These findings led to development of inorganic/organic composite membranes, which give improved mechanical stability to the membranes at elevated temperatures which improved their water retention in constrained environments. This work has demonstrated that the coupling of chemical/mechanical and electrical properties are essential to PEM operation. Recovery of Thiols for Hydrocarbon Streams. We have developed a new process that selectively removes thiols (mercaptans) from a hydrocarbon stream by selective reaction with solid metal oxides to insoluble metal thiolates. The metal thiolates can be recovered simply by filtration. A simple reactive extraction process can recover the thiols and regenerate the metal oxide for further reaction. Developing a large-scale liquid scintillation detector. TAs part of an international collaboration of physicists, we are building a detector for solar neutrinos in an underground laboratory at Gran Sasso, Italy. As chemical engineers we are principally responsible for purification of the liquid scintillator for low backgrounds and the optical properties of the liquid scintillators. This work involves extending purification technology (for example, distillation, extraction, pervaporation through membranes) to an extremes. We have demonstrated that by proper equipment design and preparation very low levels of metal impurities (10-16 g U and Th per gram of scintillator) can maintained in a multi-ton quantities of liquid scintillator.