This lecture will detail the creation of ultrasensitive sensors based on carbon nanotubes (CNTs). A central concept that a single nano- or molecular-wire spanning between two electrodes would create an exceptional sensor if binding of a molecule of interest to it would block all electronic transport. Nanowire networks of CNTs provide for a practical approximation to the single nanowire scheme. These methods include abrasion deposition and selectivity is generated by covalent and/or non-covalent binding selectors/receptors to the carbon nanotubes. Sensors for a variety of materials and cross-reactive sensor arrays will be described. A current limitation to most, it not all sensors, is chemical selectivity. Synthetic receptors can give some selectivity and when they have 3D structures can be highly specific for recognition of a molecule. However, translating complex molecular constructions into strong readable sensory signals is challenging. I will give multiple examples of how established chemical reactions that occur in solution can be used to create highly specific and sensitive sensors. There is a vast opportunity in translating the products of synthetic and catalytic chemistry into selective chemiresistive sensors. I will highlight the utility of CNT-based gas sensors for the detection of alkenes and other gases relevant to agricultural and food production/storage/transportation are being specifically targeted and can be used to create systems that increase production, manage inventories, and minimize losses.
Timothy M. Swager is the John D. MacArthur Professor of Chemistry and the Director, Deshpande Center for Technological Innovation at the Massachusetts Institute of Technology. A native of Montana, he received a BS from Montana State University in 1983 and a Ph.D. from the California Institute of Technology in 1988. After a postdoctoral appointment at MIT he was on the chemistry faculty at the Univ. of Pennsylvania and returned to MIT in of 1996 as a Professor of Chemistry and served as the Head of Chemistry from 2005-2010. He has published more than 400 peer-reviewed papers and more than 70 issued/pending patents. Swager’s honors include: Election to the National Academy of Sciences, an Honorary Doctorate from Montana State Univ., the Linus Pauling Medal, the Lemelson-MIT Award for Invention and Innovation, Election to the American Academy of Arts and Sciences, The American Chemical Society Award for Creative Invention, and The Carl S. Marvel Creative Polymer Chemistry Award (ACS). Swager’s research interests are in design, synthesis, and study of organic-based electronic, sensory, high-strength, liquid crystalline, and colloid materials. His inventions have had wide ranging commecial impact, including the FidoTM sensors, which are the world’s most sensitive explosives detectors. He is the scientific founder of 5 companies (DyNuPol, Iptyx, PolyJoule, C2 Sense, and Xibus Systems) and has served on numerous of corporate and government boards.