Having sensitive, lightweight, and portable gas-sensing systems could be helpful for a variety of different users: people with asthma searching for their triggers, soldiers at risk of chemical attack, or industrial workers facing toxic gas exposures. Ideally, a sensor would not only be able to detect a threshold amount of gas but also distinguish whether that amount accumulated over a long time or came from a short, more concentrated burst.
Howard E. Katz, professor in the Department of Materials Science and Engineering, and colleagues recently developed a sensor based on two semiconducting polymers that has this characteristic. Designed to detect nitrogen dioxide, a noxious gas that is a byproduct of some industrial processes, both polymers become more conductive when molecules of this gas attach to their surfaces. However, because one of these polymers has more of a response to nitrogen dioxide, using the two materials together can create a sensor that produces a dual readout on exposure time and concentration. The researchers are currently working on improving the stability of this device for practical use.