Polymer-Based Thermally Stable Chemiresistive Sensor for Real-Time Monitoring of NO₂ Gas Emission

We present a thermally stable, mechanically compliant, and sensitive polymer-based NO₂ gas sensor design. Interconnected nanoscale morphology driven from spinodal decomposition between conjugated polymers tethered with polar side chains and thermally stable matrix polymers offers judicious design of NO₂-sensitive and thermally tolerant thin films. The resulting chemiresitive sensors exhibit stable NO₂ sensing even at 170 °C over 6 h. Controlling the density of polar side chains along conjugated polymer backbone enables optimal design for coupling high NO₂ sensitivity, selectivity, and thermal stability of polymer sensors. Lastly, thermally stable films are used to implement chemiresistive sensors onto flexible and heat-resistant substrates and demonstrate a reliable gas sensing response even after 500 bending cycles at 170 °C. Such unprecedented sensor performance as well as environmental stability are promising for real-time monitoring of gas emission from vehicles and industrial chemical processes.