(Invited) Ionic Liquids and Gas Sensor Applications

This presentation will discuss the notable contributions to the sensor fields using ionic liquids from our laboratory. Ionic liquids (ILs) are excellent solvents that have wide varying gas solubility for common gases    and volatile organic molecules which have been demonstrated for the storage and delivery of gases that are flammable, and/or reactive. Ionic liquids also have good ionic conductivity and have been explored as nonvolatile and nonflammable electrolytes for many electrochemical device developments.  In the past ten years,   our laboratory has systematically investigated the redox mechanisms of common gases (i.e. CH₄, NO₂, SO₂, H₂, CO, CO₂, O₂)  and small organic molecules (methanol, ethanol, formaldehyde, formic acid etc.) in ILs and we have identified new reaction mechanisms for ionic liquid based gas sensor development which uniquely overcome many sensor performance challenges, especially those related to sensing capability and miniaturized sensor system implementation.  By synergistically utilizing the unique ionic liquid interface electrochemistry as well as molecular design and control of ionic liquid/conductive polymer composites, we have demonstrated new ionic liquid gas sensors enabling multiple gas detections with multiple modes detection principles via low cost and low power piezoelectric/QCM and electrochemical transducers that yields forward-thinking solutions to many gas sensors challenges, especially miniaturization and robustness.   The simplicity of the demonstrated detection principles allows for easy integration with engineering advancements such as portable electronics, networked sensing and next-generation monolithic implementation of autonomous sensors with the performance, cost, power, and operational lifetime characteristics to suit a broad range of applications.