Benicewicz held positions as a research scientist at Celanese Research Company, as senior scientist at Johnson & Johnson, and as a section leader and deputy group leader at Los Alamos National Laboratory. He joined the faculty of Rensselaer in 1997.

High-Temperature Fuel Cell Membranes

Fuel cells have emerged as one of the most promising technologies for meeting the world's energy needs in the 21st century. In the proton exchange membrane (PEM) fuel cell, the polymer membrane is considered the "heart" of a fuel cell and represents a central component in tomorrow's fuel cell industry. Recent developments in our laboratory have led to the discovery of a novel sol-gel process that produces a new membrane with high-electrolyte content, high-ionic conductivities, and excellent fuel-cell performance. These polybenzimidazole (PBI) based membranes can operate in temperatures up to 200 degrees centigrade without external humidification requirements and can tolerate high levels of carbon monoxide. Current efforts in our Fuel Cell Test Laboratory focus on the new PBI chemistry and its potential in the portable, stationary, and automotive application areas.

Polymer Synthesis

New monomer and polymer synthesis is an underlying thrust for all of our research programs. We are interested in exploring free-radical, condensation, and ring-opening polymerizations for many applications. New findings in these areas could contribute to a better understanding of the fundamental aspects and assist in new developments. Our most recent work focuses on the field of living radical polymerization using the RAFT (reversible addition-fragmentation chain-transfer polymerization) technique. These polymerizations produce polymers with narrow polydispersities and predictable molecular weights and rely on specifically designed sulfur-based chain-transfer agents to provide a high degree of control. Specifically, we developed two new synthetic procedures for the synthesis of dithioesters that eliminate many of the problems associated with their synthesis. Researchers in this field now have an improved method when preparing dithioesters that contain a variety of substituents. Additionally, synthetic methods have been expanded to easily prepare the thiocarbamates and xanthates that are utilized for specific classes of monomers. We also are pursuing the preparation of various molecular architectures (block, star, and gradient) using living radical polymerization. In addition, we are focusing on the controlled polymerization of polymer chains from the surface of silica nanoparticles in order to support research in the Rensselaer Nanotechnology Center.

Conducting Polymers

Our research has shown that conducting polymers, such as polyaniline, are effective at inhibiting corrosion on metal surfaces. We now seek a better understanding of the interrelationships between electrical conductivity, redox behavior, and corrosion inhibition. We also are exploring new synthetic approaches to processable conducting polymers. Acrylate and acrylamide monomers containing short-chain aniline oligomers have been prepared and polymerized by standard free-radical polymerization techniques. These polymers have shown redox behavior similar to that observed in high molecular-weight polyaniline, even though the oligoaniline units are two to four repeat units in length. Structure-property relationships in this class of polymers are being investigated as well.

Liquid Crystalline Polymers and Thermosets

Liquid crystalline polymers are under intense investigation due to the unique physical, mechanical, and electrical properties imparted by the ordered phases of these materials. Synthetic efforts are focused on the design and preparation of new polymers with specific properties. Liquid crystalline thermosets are being investigated as new high-performance crosslinked polymers for structural applications. We have recently demonstrated that magnetic field alignment of LCT's produces large increases in tensile modulus along the direction of orientation. The use of these materials in nanocomposites is also being investigated. Linear liquid crystalline polyamides and polyesters have been commercialized as high-strength fibers and molded plastics. Attempts to modify their properties with molecular kinks, swivels, bends, and side groups have resulted in a trade-off between increased processability and lower physical properties. We are preparing monomers and polymers using a new design concept called main-chain asymmetry to maintain processability, while exploring structures that could lead to higher physical properties. New catalysts are also being tested to reduce polymerization times and increase molecular weights.