Abstract
Detection of organic vapors is a lasting challenge. There is a growing concern over possible health effects of long-term exposure to organic vapors in house as well as workplace environments. In this paper, we report a successful strategy for the detection of toxic organic vapors, e.g., ethyl acetate. Quartz crystal microbalance (QCM)-based sensors are fabricated with <200 nm thick films of molecularly imprinted polyurethane-gold nanoparticle composites (PU-AuNPs). These sensors are employed for real-time monitoring of ethyl acetate, acetone, and methanol vapors. Gold nanoparticles (AuNPs) are produced chemically using Duff procedure and subsequently, incorporated into ethyl acetate imprinted polyurethane (PU) pre-polymer to prepare highly sensitive PU-AuNPs composite films. The sensors perform selectively through weak affinity interactions with the target analytes. It is due to the imprinting effect of ethyl acetate and the inclusion of AuNPs that PU-AuNPs composite films show synergistic sensor response of 0.221 Hz/ppm towards ethyl acetate vapors, which is even higher than the combined sensor effect of imprinted PU (i.e., 0.085 Hz/ppm) and pristine AuNPs (i.e., 0.128 Hz/ppm). In addition, these sensors exhibited reversible signals with sharp response and recovery times, usually <40 s at room temperature, and detection limit of <1.4 ppm.