Intense Pulsed Light-Treated Near-Field Electrospun Nanofiber on a Quartz Tuning Fork for Multimodal Gas Sensors.

Accurate and portable gas sensors are required for environmental monitoring, locating leakages, and detecting trace chemical vapors or gases. Although many sensors have been developed, few can rapidly and selectively detect parts per million (ppm) concentration changes. In this work, we fabricate multimodal gas sensors by depositing a single nanocomposite fiber between the prongs of a quartz tuning fork (QTF). The resulting sensors are portable and integrate multimodal approaches by applying both chemo-mechanical sensing for sensitivity and electrochemical sensing for selectivity. Near-field electrospinning (NFES) produces a flexible and semiconductive nanocomposite fiber with ∼500 nm diameter that can be integrated into electronic systems as environmental gas sensors. Intense pulsed light (IPL) and sputter coating improve adhesion of the nanocomposite fiber onto a QTF. Furthermore, IPL offers improved sensing performance due to the higher specific surface area and reduction in polymer content. In this study, hydrogen gas (H2) is chosen as a target gas since it is a common energy source in fuel cell applications and byproduct in chemical reactions. An electrospinning solution containing polyaniline, multiwalled carbon nanotubes, and platinum nanoparticles is used to test H2 gas sensing performance. The resulting multimodal sensors are selective to hydrogen versus other gases and vapors including methane, hexane, toluene, ammonia, ethanol, carbon dioxide, and oxygen. Furthermore, the sensors detect ppm levels of hydrogen gas even in the presence of high humidity that typically hinders gas sensor performance. The development of this sensor leads to a new method for compact and portable multimodal gas sensing.